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The engineer and materials of today
The engineer and materials of today Thoughts on the education of engineers and designers in metals, their alloys and other materials Dr E. G. WEST, OBE, CEng, FIM* • Consultant. Past President of the Institution of Metallurgists. The educathm ~ f engineers in materials involves man.r problems f o r teachers and students..for the professhmal blstitutions and &~r industry. The increasing awareness Of the need to conserve energy and to optimise the use o f metals and other engineering materials must lead to the reappraisal t~f the design .function in relation to the selection o f materials and manufacturing operathms. There is no attempt at .u'llabus building hut the interdisciplinary nature o f materials studies is illustrated by re/'erences to steels and nonferrous metals, welding and t'orrosion protecthm. The need to use e[]'ectivelv all the sourt'e.t o f available infi~rmation and the value o f case studies are enwhasised.
Engineers today, as in ancient times, are responsible for designing, manufacturing and building the multitude of artefacts required by everyday activities dwellings to provide shelter from the weather: buildings in which work is undertaken: machinery to increase production of tools, domestic goods and food required: power plant to provide heat. light and energy: water supply and sewage systems: the means of transport by land, sea and air: and the equipment needed to manufacture the chemical compounds and all the other items which make today's material civilisation. Additionally he is responsible for providing the means 1o fill the increasing leisure time of the population, to assist education and to provide life support systems - the list is endless- and for every single item the engineer needs the suitable materials available in the required quantities at an economic cost. The problems inherent in their selection have become more complex through the ages but today it is more important than ever before to overcome the conservatism of the engineer and to improve the interface between the providers and the users of metals and other materials. There has always been a problem in
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reconciling the engineering needs with the availability of materials, in educating designers in the properties of today's materials and in demonstrating how to use them in the public interest. There is no doubt that a new approach is necessary and looking back for only halfa century indicates why a new approach is essential. In the 1920s the engineer was happily using cast iron and mild steel as his principal materials of construction and it was fortunate that they could be described as good tempered materials with a large tolerance which helped in both design and production. The other principal metal required by the engineer at the time was copper which fifty years earlier, had become the major conductor for the evergrowing electrical power being used. Copper alloys, particularly brass fittings and a multitude of other applications, was the next material in wide usecoupled with smaller quantities of the other common metals: lead, for plumbing, roofing and batteries, zinc for protecting steel, a l u m i n i u m t h e n b e c o m i n g important through its strong alloys, and stainless steel just beginning to find acceptance. There were a few alloy steels, such as the manganese steels for wear resistance, the nickel case hardening steels and a growing range of tool steels. Nickel was coming into wider use, particularly for electro-plating and its alloys with copper, chromium was gaining acceptance as a plated finish and magnesium was being introduced in Germany. At the same time a range of new polymer materials was being developed. Since World War 11 the number of widely used metals and alloys has increased many fold and the traditional beating of swords into plough shares has continued at a high rate - even though today this is usually termed 'spin off'. Threats of war have called for still more
s o p h i s t i c a t e d a r m a m e n t s and the inevitable tide of technology has led to mass travel and the development of satellites, with their c o n c o m i t a n t demands on materials. Now the metallurgist, the mining engineer, the geologist and the oil technologist are all warning of shortages of raw materials, and their words are confirmed by the very. steep increase in prices of energy and metals, leading to i m m e d i a t e i n f l a t i o n a r y pressures and the need for better long term conservation. The challenge must be met by using metals with much greater efficiency than ever before and seeking alternatives which will permit the present material standard of living to remain at least steady, even though it will be impossible for the already developed nations to continue consuming materials at anything like their present rate. Fortunately. research in many fields is already showing possible means of mitigating some of the effects of our too rapid consumption of natural resources, but time for action is limited. In addition to the scientific and technological problems, there have been major shifts in economics, in the widest sense, through such changes as the development of Third World industries, and disturbances in the traditional relationship of the costs of materials and labour. However, new lines of thought are becoming accepted by politicians and public, helped by the wider use of modern methods of communication and the engineering developments which have made them possible by miniaturisation. Engineering research has greatly increased and developments in engineering design concepts have made the profession still more aware of the need for specific education in materials allied with production factors and overall economics which include both first cost and maintenance expenditure. It must
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not be forgotten that the fundamental basis of design has always depended upon the materials available. Thus, early buildings were based upon the properties of timber used as columns and beams. When new tool materials made it possible to shape stone, the basic design of columns remained the same with timber continuing in use as beams for lintels and roofs. The development of the arch furthered the building of stone and brick structures but with the advent of cheap metals further changes were necessary and it is interesting that the first iron bridge was designed on the principles of carpentry and joinery. The tensile properties of steel led to yet another step in structural design and the bases of engineering to date were established little more than 150 years ago. Experience with the aluminium alloys for aircraft and the availability of higher tensile steels permitted the stressed skin and box girder designs to be accepted with increased efficiency in the application of materials. Specifications based on factors of safety were developed still more recently in place of the former 'factors of ignorance', but today such overall factors are giving way to the concept of partial factors using the limit state principle of design. The limit state method uses the computer to analyse the effects of stresses due to loading in combination with the other facets involved, the characteristics of the working environment over the projected lifespan of the artefact and fabrication procedures including workmanship imperfections. Thus, greater precision becomes possible which makes it still more essential to have and to understand all possible information on materials that is relevant to the design. Alongside such new design concepts and the research on which they are based, there have been many new materials developed and better understanding of properties of the old and the new. Engineers and the industries they serve tend to accept many of the results of research much too slowly but the need to save material through design is at last in the forefront of thinking on design. That it is a long drawn out operation is seen from many examples: thus, the plastic theory of design was developed by Sir John Baker more than a generation ago but is still not fully accepted as standard practice. It may well be asked how is the mass of new information to be taught? How is it to be assimilated? What must be taught to engineers not only at the undergraduate level but on a continuing basis through a professional career? These are only a few
of the many questions requiring answers which must be based on positive thinking and which must also be related to the needs of different parts of the world and of individual countries. The principles are of universal application but space permits only a discussion of the position in the UK. There is no doubt that all engineers from ONC technicians to post doctoral consultants require full quantified information about all properties as well as reliable data on the effects of fabrication and service conditions on these properties, taking account of wear, corrosion, fatigue, creep, the characteristics of fracture, effects of temperature, etc. Modern engineering requires that all engineers should take their responsibility seriously in using up to date information effectively. Engineering education, it was felt, may not have kept pace with the best means of using available data and some two years ago the Council of Engineering Institutions together with the Design Council asked the Institution of Metallurgists for help in considering this problem. The Design Council had previously published the findings of a Committee, chaired by MoultonJ which set out the requirements for educating industrial designers but with the deliberate omission of r e c o m m e n d a t i o n s on materials as they demanded specialist attention. After a series of meetings a report was published2 and subsequently the Fellowship of Engineering issued its own statement.3 These documents confirmed the need for new thinking, defined the problems and made certain recommendations. However, the discussions made it clear that there is no universal solution even when the problems have been analysed. Two distinct requirements emerged, however, the first emphasising the design stage and the second raising matters concerned with production, whilst economic factors were common to both.
The engineer's responsibilities Education of engineers in materials must be considered with respect to the responsibilities undertaken at three principal levels which can be readily defined by referring to the grades recognised by the Council of Engineering Institutions for registration through the Engineers' Registration Board. The Chartered Engineer (CEng) is competent by virtue of his fundamental education, training and experience to apply the scientific method and outlook to the analysis and solution of
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engineering problems, with personal responsibility in research ~md design, in m a n u f a c t u r e and c o n s t r u c t i o n , in management and in education. His work is predominantly intellectual and requires the exercise of original thought, plus the ability to supervise the work of others, both technically and administratively. By his education he is able to follow progress in his branch of engineering and to apply new knowledge independently, thus making contributions to the development of e n g i n e e r i n g science and its applications. The Chartered Engineer who must be a corporate member of the professional institution relevant to his knowledge, is normally required to have an Honours degree and must have undergone periods of training and experience. He is the spearhead of engineering in industry. The Technician Engineer (Tech.Eng.) is competent through his education, training and experience to exercise indep e n d e n t t e c h n i c a l j u d g m e n t in engineering, with personal responsibility for duties in his field. He understands the reasons for and the purpose of operations within his responsibility. He undertakes technical work of an established or of novel character either independently or under the direction of a Chartered Engineer, and he is able to lead. He must also bea corporate member of the appropriate professional institution and his minimum qualification is the HNC or HND or CGLI Full Technologist Certificate, though often he is a graduate. The Technician (Tech.) is able through his education, practical training and experience to apply proven techniques or procedures, with a measure of responsibility under the guidance of a Chartered Engineer or Technician Engineer. He must be able to communicate clearly and must be the holder of an ONC or CGLI Part2 certificate, as well as being a member of the relevam institution. In future, technicians and many technician engineers will be educated largely in colleges through the modules and prorammes validated by the Technician Education Council instead of the CGLI, ONC, HNC and HND schemes which are being phased out as they are replaced by TEC routes. Today there are 16 Corporation and 7 Affiliate Members of the Council of Engineering Institutions, with some 40 institutions registered with Technician Engineer or Technician Boards, representing in total about 200 000 individuals. Some ten thousand new graduates qualify in engineering and technology
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each year from British universities and polytechnics, with rather smaller numbers taking examinations which can lead to the professional qualifications of Tech.Eng. and Tech. It may be noted that it is a requirement of the CEI that its m e m b e r institutions provide Chartered Engineers, Technician Engineers and Technicians with a journal and other publications to enable them to maintain an interest and keep up to date. in their professional r e q u i r e m e n t s , including new materials and techniques. It should be part of the remit of the engineering institutions to publish relevant data on materials as they become available, on new uses of well known materials, and the overall economics of materials selection, as well as drawing attention to research affecting materials usage. For the exercise of their responsibilities all these new entrants to the profession require sound knowledge of materials and their uses, but the young engineer cannot possibly learn all that he requires to know about materials even at the start of his career. The basic principles and an a w a r e n e s s of the p r o b l e m s would probably be the most that could be inculcated, but industrial training should include an additional content of materials related to i h e j o b function. The modes of failure in service and the causes of difficulties in production provide many opportunities for furthering knowledge of. and interest in, materials. Clearly teaching requirements must be based on close collaboration between the design and production functions of e n g i n e e r i n g d e p a r t m e n t s a n d the corresponding departments concerned p r i m a r i l y with m e t a l s a n d o t h e r m a t e r i a l s . W h e r e s a t i s f a c t o r y cooperation exists the resulting graduates have excellent a p p r e c i a t i o n of the problems of materials but in some areas it is clear that certain courses are less integrated. As m a n y decisions on materials are taken in practice by technicians it is unfortunate that there appears to be relatively less attention to this topic than is desirable. Design procedures It is not easy to set down the design procedures in industry or to identify the point at which decisions on materials are made. Major capital projects, such as an oil refinery or a new fully equipped factory, are the result of design work by a t e a m of specialists able to include, or call upon, experts in related disciplines, and the team should have available the services of a metallurgist or materials
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engineer. At the other end of the scale, the small firm making a relatively few assemblies may not have anyone responsible for material decisions, and even c o m p a n i e s m a n u f a c t u r i n g for the consumer market may employ only a single person to design a product, select materials and get it into production. In these cases reliable information at the design stage and later, during production, is essential from independent experts or suppliers. It would be an impossible task to analyse and determine where decision making on materials actually occurs in practice. The initial concept for the production of a piece of equipment for general sale may be a d e m a n d from the Marketing Division of a large c o m p a n y or the result of an 'imagineering'creator. From this concept designs are fixed, first on paper and then as prototypes. At some point materials are selected, but this is often determined in the Drawing Office by a technician. This choice is then subject to change as a result of tests or through the d e m a n d s of production management or by economic factors through the purchaser office. It is often evident that the final selection of material has not been the decision of a design team, or even of a chief designer, and many case studies show the need for not only the education of engineers and technicians but also production management and purchasing officers in how to handle their respective functions responsibly and knowledgeably in concert with the materials engineer and the supplier. Too often the metallurgist is placed in the same p o s i t i o n as the m o r b i d pathologist to investigate and pronounce on the cause of failure rather than being consulted or, better still, being part of the team responsible for a product from its conceptual design through the prototype stage and its testing to final production and sale to satisfied customers. Many examples could illustrate the need for cooperation in detailed design and continually t h r o u g h o u t the p r o d u c t i o n sequence. Thus, drawings should invariably carry the correct, up to date reference to the material, preferably specified in terms of a British Standard instead of the still too c o m m o n reference to such non-informative words as "AI" or 'Alum" or 'Cast Aluminium" or "Cast Brass' the list is endless. Even when a correct specification reference is given on a drawing it is often qualified by the addition of "commercial grade' which appears to indicate, in the mind of the decision maker, that it is not worth paying for the correct material backed by
quality assurance and relevant testing. It is easy to go even further down such roads to failure as when the product properly designed with specified materials is virtually redesigned in the Purchase Office in order to save odd pence without reference back. It may not be realised that when ordering, for example, "commercial grade l,G4' the purchaser is asking for a leaded gunmetal casting to a nominal composition only, with little attention to the level of impurity content and without the benefit of melt quality tests or any Certificate of Compliance as required by the General Clauses of BSI400. This S t a n d a r d includes also a code to cover the means of inspection available to the purchaser and indeed draws attention to the desirability of including on the order the appropriate coding to determine whether radiographic or other tests are necessary in relation to the actual application. In general, m a j o r decisions on materials should not be, and probably are not, taken by newly qualified engineers or technicians without reference to higher authority, but sometimes senior staff may not be as fully informed a b o u t new materials or new developments in fabricating techniques as those with more recent training. W h a t should be taught? This is not an attempt at syllabus building or even of stating 'learning objectives', all of which are the subject of much debate, resulting in as many d o c u m e n t s as there are Departments of Engineering in their many forms and at various levels from O N C to higher degrees. Perhaps the most useful first point to be emphasised at all student levels is the interdisciplinary nature of materials studies in relation to design and production. The decreasing availability and increasing costs of materials bring this home to engineers in industry, a n d the c o m p l e x i t i e s in materials selection require explanation from the outset of every course. Teachers s h o u l d p r o v i d e an i n t e g r a t e d and coherent materials content t h r o u g h o u t each course, varying in emphasis and depth according to the level from technician to postgraduate. The engineer requires p r i m a r i l y quantified properties on a uniform basis covering all the materials he is likely (or even unlikely) to use in practice to meet the demands of production and service. but he is usually given, and often uses, only the figures based on standard specifications. These are confined to tensile strength, with yield point or p r o o f stress m i n i m a , some i n d i c a t i o n of
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ductility usually in the form of elongation as a percentage of gauge length and, perhaps. hardness, but these are no more than the minimum required by standardised tests for quality control purposes. Certainly in the case of cast metals, they may bear little relation to the strength properties of actual castings due to the important influence of such factors as the section thickness, the rate of cooling, the absence of porosity and variations from skin to core. The designer must be able to assess the need for. and to use. information on the modes of failure by steady stressing, impact loading and fatigue including notch sensitivity, creep and corrosion. Numerical data require much time and effort for their determination and interpretation. Other attributes which may require special testing are bearing characteristics, wear resistance and the combination of stressing and chemical attack known as stress corrosion. The effects of temperature are of increasing importance not only when these are significantly above or below ambient but also within the ranges n o r m a l l y encountered in every-day environments, such as the winter climate of the North Sea which can result in brittle fracture, or the slightly raised temperatures of electrical equipment which could lead to failure by creep. The production engineer requires data on machining, cold working limits, temperature ranges for forgingand stamping, weldability by various processes and finishing operations (which, being last in the manufacturing sequence, are often the source of trouble and delay). Information should be numerically oriented though there are limitations to the extent to which this is possible. The effect of fabrication on properties is often but little understood especially when welding is considered. The heataffected zone is probably that part of the cross-section of a weld that is most subject to defects and hence fraught with dangers. On metal that has been strengthened by cold working, this zone is inevitably softened as it is also in precipitation-hardened alloys. In the case of steels, it may well show great reductions in ductility and increases in hardness. It may also exhibit serious reductions in corrosion resistance due to partial melting or the segregation of alloying elements or impurities. Hence there is a need for at least an appreciation of the effects of working, heat treatment and fabrication operations on properties. Corrosion and protection are particularly interesting topics especially as
increasing attention is now given to reducing the need for maintenance with its high labour content. The study in depth of corrosion phenomena does not fall within the province of the engineer but means of reducing corrosion require an appreciation of the background in order that the precautions taken can be properly understood. An introduction to the electrochemical basis of corrosion is thus desirable and an engineer with "A" level knowledge of physics a n d / o r chemistry should well cope with this. Perhaps it suffices for the engineer to be aware of the problems, coupled with the need to consult the metallurgist/corrosion technologist, and to supplement this by the recently published Design Guide and the BSI Commentary on Bimetallic Corrosion. 4 It is becoming more widely accepted that the cost of a metal or an alloy, a composite or a non-metallic material should be ta ken into account as another property at the design stage but this is not easy because metal prices fluctuate over quite short periods. They may change significantly between the drawing board and prototype, as well as in later stages of production, and whilst the trend is generally upwards, there are times when substantial variations occur in the relative costs of competitive materials within short periods. It is more difficult to make due allowance for factors of availability and price than for alterations in mechanical properties which are less likely to occur hence the need to be aware of the need again to consult the materials expert who at least should be able to offer advice on likely trends. The basis of using the cost of each unit of tensile strength (or yield stress) has been well outlined by W. O. Alexander 5 and in due course may be accepted more widely, together with consideration of the energy content of a material. When decisions are being taken on the content of appropriate lecture courses, it is often easier to consider what is not required by the engineer. Thus, the production of metals from their ores or the manufacture of polymers from mineral oils or vegetables and animal sources can be taken as unnecessary, even though the engineer is rightly involved with the plant required for the processes concerned. It would also be agreed that the engineer's syllabus need not include alloy theory as propounded by Hume-Rothery of the Oxford School or G. V. Raynor or other specialists in metal physics and this side of physical metallurgy. The full treatment of crystallography and of dislocation theory are again beyond the scope of
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engineering courses but they impinge on design and production in such matters as notch sensitivity and fracture mechanics. The engineer should be aware that trace elements may have an important affect on engineering properties but again he need not be concerned with the minutiae of the reasons for their effects. Unwanted i m p u r i t i e s a n d , indeed, d e l i b e r a t e additions of trace elements are controlled in accordance with British Standards produced by expert Technical Comm i t t e e s on w h i c h the m a t e r i a l engineer~ ,metallurgist takes responsibility for setting limits. It is however desirable to avoid the development of anything akin to the "mysteries" of the ancient Guilds and the properly developed course with an integrated teaching staff can readily avoid this risk by covering selected facets of metallurgy based on the results of a major research programme. Many examples can be cited as suitable for such treatment and mention may be made of the current position of structural steels required for modern welding procedures. Steel technology has made such significant advances in the last 12-15 years that it is not surprising some engineers feel unable to differentiate between the uses of various grades offered by the steelmaker. Furthermore, it may be unfair to expect them to do so in the absence of reasonably simplified guides to the purpose of the alloying e l e m e n t s a d d e d to give specific properties. Modern steelmaking permits the ready production of virtually tailormade steels to fit the requirements of strength, impact properties at low temperatures, forming and weldability. Detailed studies have shown the effects of carbon and manganese contents to give optimum yield strength and toughness, combined with control of grain size by alloying addition of niobium and vanadium, related to rolling and heat treatment conditions. The range of steels for structural purposes has been stabilised and should facilitate teaching in engineering departments concerned with the design of those structures which account for a high proportion of steel usage today. Their potential benefits can be exploited, however, only by basing designs on yield strength and taking advantage of their good welding properties and ready formability. For their effective application it would be desirable for the graduate engineer to have sufficient understanding of the basic metallurgy of steel to enable him to appreciate the need for care in selection and precautions in use. Thus, the
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problem of hydrogen cracking in welded steels should be touched upon but again without including the full knowledge required by the welding engineer or metallurgist responsible for specifying the procedures covered in detail in a Welding Institute handbook. 6 Likewise the types of stainless steel should be outlined including their corrosion resisting and working properties, with particular attention to the need for minor alloying.elements to stabilise the structure of the steel when it is welded. This is a comparatively simple teaching task, but consideration of the non-ferrous metals and their multitudinous alloys is much more formidable. Copper is used commercially in about ten grades and its alloys are covered by well over 100 British Standards, whilst aluminium and its alloys require some 40 General Purpose Specifications in the UK with others for aircraft applications. When magnesium, nickel, tin, lead and zinc are added to the list they bring total British Standards to more than 200 and then there are the metals and alloys not the subject of specifications. Many of the non-metallic engineering materials are not covered by British Standards and data must be obtained from suppliers, other sources or specialists. Thus only an outline of these ranges of niaterials can be given in the available teaching time and this must include references to sources of information. Sources of i n f o r m a t i o n
The means of obtaining information have increased in scope and speed but many technologists appear to receive little training in using either the old or the new methods of data retrieval. The rapidly developing computerised procedures, based on key words and a standard thesaurus, require expert tuition for their efficient use - not least on how to pose questions to give the information needed. They are not, at present, an effective alternative to first hand acquaintance with tabulated data or with the original literature. Courses for technicians and engineers should therefore include not only an e~ement of how to use sources of data but also encouragement to at least scan preferably study original material. There has been a great deal said (and .accepted) about the need for engineers to be numerate but they must enjoy being literate! The various engineering handbooks published commercially, such as the well known Kempes or the more specialised ones devoted to specific industries, provide useful initial guidance but are not
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invariably up to date. The resources of the Research Associations are generally excellent in their own and related fields but new data in research reports and theses are not always readily available. Reference libraries are usually nonspecialist except when they belong to a professional institution or learned society. Major consultants maintain their own data banks and the largest industrial companies are able to service their designers and engineers through their own information departments. Other sources of readily usable data include the Fulmer Materials Optimiser 7 and the series of Design Guides ~ to which additions are still being made. The educators must teach how such information aids should be used and also how computerised data banks should be approached to yield appropriate answers to questions posed by engineers. The education and training of a designer should make him capable of'digging" for information for "special requirements'. A particularly important topic to be covered in an undergraduate course or a short course for in-career education is the use of British Standards - the specifications of other countries and the ISO including the value of the data and advice given in some of them as Appendices or Guidance Notes "For Information Only'. Thus, again referring to BSI400, the thirty alloys listed therein are divided into three groups, A, B and C, of which the first are the twelve alloys in common use and hence available more readily and at lower prices than those in groups B and C useful commercial guidance not always considered to be appropriate to, or available in, a Standard. Likewise, there is essential information in many of the standards for welding consumables which should be included on drawings and purchase requirements. Therefore the correct use of British Standards is an essential part of education which often becomes apparent only later when failures have been the result of lack of understanding- leading to legal actions if not inquests! The teacher at every level should have had first hand experience of the problem of finding readily usable design data and so be able to illustrate his themes by personal examples. This leads to considering the means by which actual industrial experience in the various design fields can be brought to bear in educational establishments, in addition to academic staff making and renewing their own contacts with manufacturing concerns. Visiting professorships could be more often arranged, lectures by part
time staff from industry or consulting organisations are of value and the study of case histories provide particularly useful lessons. C a s e studies
The presentation and discussion of ease studies is one of the most rewarding m e a n s of t e a c h i n g e n g i n e e r s the importance of materials selection taking account of fabrication, economics and quality assurance aspects. It is, however, not easy to obtain detailed accounts of how decisions were arrived at, how judgement had been exercised and how much part was played by experience which is often difficult to pin down, let alone quantify. It is difficult to obtain reliable information from either industrial successes or from the investigation of failures because of commercial considerations and the risks of disclosure of useful i n f o r m a t i o n to c o m p e t i t o r s . Case histories of failures are perhaps easier to obtain providing that anonymity can be preserved. It is significant that the British Case Study Clearing House at the Cranfield I n s t i t u t e of T e c h n o l o g y is being developed to cover engineering topics and this may well provide new bases for teaching. The c o o p e r a t i o n of professional institutions can help to make such information available from their individual merribers, and the assistance of Research Associations should also be sought. Direct industrial experience of teachers in universities and polytechnics is an important factor in success, and should be supplemented by lecturers from industry or consulting firms. A specific point to be made concerns the need to test prototypes and production models to destruction and to relate the results to the input of data at each stage. Lessons learned and applied provide valuable case study material and if such testing and checking of prototypes (or early production models) can be undertaken in university or college laboratories an air of reality can be given to lectures and tutorials which may otherwise appear to students to be too remote from an industrial job.
Progress It may well be argued that such a full and varied content must lead inevitably to longer courses with engineering undergraduates requiring four instead of three years to first degree level or the option of a further year for a taught MSc to cover materials in the depth required by the designer in today's industries. The content of any specific course must be
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decided only after close consultation with industry to ensure that too much theory is not included at the expense of practical engineering experience. Industries differ in their approach to sophistication in design and there are major variations between sectors such as aeronautical engineering and shipbuilding. Some sectors are conscious of value engineering, some aim for minimum maintenance over long periods, some rely on large factors of safety - the designer cannot be expected to become expert in all the variants. Hence, industry must provide facilities for training, as well as advise on course contents, for the design engineer and industrial designers whom it hopes to employ. Many academics advocate concentration on materials in postgraduate courses and a particularly valuable example is provided by the Cranfield Institute of Technology which recently created a Centre of Engineering Design where special attention is inevitably paid to materials selection. In the last few years valuable initiatives have emerged at a number of universities: for example, at Bradford two main courses, one in mechanical engineering design and one based on manufacturing design, have a common sector for materials and these sandwich-based courses provided valuable practical experience of materials throughout the four-year period involved. Likewise at Sheffield, Southampton and Bath there have been new approaches at undergraduate level and at Imperial College in London an MSc course in Design ran alongside a Master of Design course in association with the Royal College of
Design. The industrial designer is essentially aesthetic in his approach and may pursue such associated topics as ergonomics. The more numerate engineering designer is concerned with analysing a problem mathematically leading to designs which depend on accurate data on the properties of materials. In all engineering design a knowledge of materials is essential but specific quantitative data require also experience in their use and the ability to obtain the cooperation of the materials specialist, particularly where depth of knowledge is required, such as on brittle fracture. In some University Civil Engineering Departments, I0% of undergraduate time may be devoted to materials but the proportion tends to be lower in other engineering disciplines. Usually teaching is best done by specialists from the metallurgical or materials science departments but close cooperation between departments is essential and there are many opportunities for improvement in this. A joint effort might bring to fruition a scheme to help teachers through the professional institutions most directly concerned - the metallurgists with the mechanical and production engineers -. to provide a service on materials in manufacturing industries for use by the engineering designer and production engineer. Whilst the case has been made for the undergraduate going into engineering to have knowledge of materials and early experience in their use, it is just as important for the metallurgist/materials specialist to be aware of the basic principles of design so that he is able to appreciate the problems encountered by
the designer. To each side c o m munication of knowledge is obviously essential and calls for each to understand the accepted terminology be it words. mathematical formulae, drawings or a computer print out. It must be appreciated that an engineer with a veneer of materials knowledge is of no more value than a metallurgist with a smattering of engineering. Acknowledgement is gladly given to the many friends who have given their views at various times and to those who attended the meetings which led to the reports mentioned in this article. References I. Engineering
Design Education. Design Council 1976 Report on current education of engineering designers. 2. Report on "Education of Design Engineers and Industrial Designers in the Use of Materials" submitted to the Design Council. July 1977: The Metallurgist & Materials Techmthtgist. Jan. 1978. 3. Report on 'Education of Engineers and Technicians in Relation to Materials', Nov. 1978. published by the Fellowship of Engineering. London SWI. price £1.50. 4. Metal Corrosion, T. K. Ross. Oxford University Press, No. 21, 1977 PD6484:1979 Commentarr on Corrosion at Bimetallic Contacts and its Allet'iation. BSI. London 5
WI. For example, W.O. Alexander and P. M. Appoo. Metals & Materials. July/August 1976, pp42-45.
6. Welding Steels Without Hydrogen Cracking. F.R. Coe, Welding Institute publi-
cation 1973, 68 pp. Materials Oplimiser. Fulmer Research Institute, Stoke Poges. Bucks. SL24QD. 8. Engineering Design Guides, Design Centre. 28 H a y m a r k e t , London SWIY 4S U. and Oxford University Press. 7. Fulmer
International Conference "The implication of materials selection on product liability" The proceedings of this conference held in September 1979 will be published by Scientific & Technical Press and will be available early in 1980 price £25. The following papers will be presented: I. The current and potential l e p l requirements for product liability in UK, Europe and USA. B. D. Monk. MBG Management Consultants Ltd. 2. Product faaum due to bad material choice and processing. N~ A. Waterman, Fulmer Reseurch Institute. 3. Safety in chemical proce~ plant. C. Edeleanu, Cambridge Univerztty. 4. The implications of equipment materials selection on product liabifity in food processing. C. D. Marriott. Unilever Research Laboratory, Colworth House, Bedford. 5, Product quality, product liability and oil products, R. Lindsay, Shell UK Ltd. 6. Testing for product liability.D.B.S. Berry. Yarrley Technical Centre. ]'rowers Way, RedhiU, Surrey. 7. Materiels selection for durability. P. Watson. GKN Group Technology Centre. Birmingham New Road, Wolverhampton.
MATERIALS IN ENGINEERING APPLICATIONS. Vol. 1. September 1979
8. Materials used in manufacture of consumer goods. D. J. Unwin. Consumers" Associntion, Research Division Laboratories, Harpenden Rise Laboratory, Harpenden, Harts. 9. D,I.Y. Products. A. Treadwell, Black and Decker liraland) Ltd., Naa$, Republic o f Ireland. I0, Elastomer ageing and product liability.J.N. Ha~rsand D. Norbury, Dunlop Ltd., Research Centre, Kinglbury Road, Birmingham. I I, Contribution of condition monitoring to the elimination of failure in service. M. J. Neale, Michael Neale & Associates, 43 Downing Street, Farnham, Surrey. 12. The insunmce of product liability. P. Sherman, Royal Insurance Company Ltd., t>.(2. Box 144, New Hull Place, Liverpool,
Orders to Scientific and Technical Press, Chilbcrton Holtle. Doods Road, Reigate. Surrey, England - Tel: Relgate (07372) 43521.
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Engineers today, as in ancient times, are responsible for designing, manufacturing and building the multitude of artefacts required by everyday activities dwellings to provide shelter from the weather: buildings in which work is undertaken: machinery to increase production of tools, domestic goods and food required: power plant to provide heat. light and energy: water supply and sewage systems: the means of transport by land, sea and air: and the equipment needed to manufacture the chemical compounds and all the other items which make today's material civilisation. Additionally he is responsible for providing the means 1o fill the increasing leisure time of the population, to assist education and to provide life support systems - the list is endless- and for every single item the engineer needs the suitable materials available in the required quantities at an economic cost. The problems inherent in their selection have become more complex through the ages but today it is more important than ever before to overcome the conservatism of the engineer and to improve the interface between the providers and the users of metals and other materials. There has always been a problem in
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reconciling the engineering needs with the availability of materials, in educating designers in the properties of today's materials and in demonstrating how to use them in the public interest. There is no doubt that a new approach is necessary and looking back for only halfa century indicates why a new approach is essential. In the 1920s the engineer was happily using cast iron and mild steel as his principal materials of construction and it was fortunate that they could be described as good tempered materials with a large tolerance which helped in both design and production. The other principal metal required by the engineer at the time was copper which fifty years earlier, had become the major conductor for the evergrowing electrical power being used. Copper alloys, particularly brass fittings and a multitude of other applications, was the next material in wide usecoupled with smaller quantities of the other common metals: lead, for plumbing, roofing and batteries, zinc for protecting steel, a l u m i n i u m t h e n b e c o m i n g important through its strong alloys, and stainless steel just beginning to find acceptance. There were a few alloy steels, such as the manganese steels for wear resistance, the nickel case hardening steels and a growing range of tool steels. Nickel was coming into wider use, particularly for electro-plating and its alloys with copper, chromium was gaining acceptance as a plated finish and magnesium was being introduced in Germany. At the same time a range of new polymer materials was being developed. Since World War 11 the number of widely used metals and alloys has increased many fold and the traditional beating of swords into plough shares has continued at a high rate - even though today this is usually termed 'spin off'. Threats of war have called for still more
s o p h i s t i c a t e d a r m a m e n t s and the inevitable tide of technology has led to mass travel and the development of satellites, with their c o n c o m i t a n t demands on materials. Now the metallurgist, the mining engineer, the geologist and the oil technologist are all warning of shortages of raw materials, and their words are confirmed by the very. steep increase in prices of energy and metals, leading to i m m e d i a t e i n f l a t i o n a r y pressures and the need for better long term conservation. The challenge must be met by using metals with much greater efficiency than ever before and seeking alternatives which will permit the present material standard of living to remain at least steady, even though it will be impossible for the already developed nations to continue consuming materials at anything like their present rate. Fortunately. research in many fields is already showing possible means of mitigating some of the effects of our too rapid consumption of natural resources, but time for action is limited. In addition to the scientific and technological problems, there have been major shifts in economics, in the widest sense, through such changes as the development of Third World industries, and disturbances in the traditional relationship of the costs of materials and labour. However, new lines of thought are becoming accepted by politicians and public, helped by the wider use of modern methods of communication and the engineering developments which have made them possible by miniaturisation. Engineering research has greatly increased and developments in engineering design concepts have made the profession still more aware of the need for specific education in materials allied with production factors and overall economics which include both first cost and maintenance expenditure. It must
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not be forgotten that the fundamental basis of design has always depended upon the materials available. Thus, early buildings were based upon the properties of timber used as columns and beams. When new tool materials made it possible to shape stone, the basic design of columns remained the same with timber continuing in use as beams for lintels and roofs. The development of the arch furthered the building of stone and brick structures but with the advent of cheap metals further changes were necessary and it is interesting that the first iron bridge was designed on the principles of carpentry and joinery. The tensile properties of steel led to yet another step in structural design and the bases of engineering to date were established little more than 150 years ago. Experience with the aluminium alloys for aircraft and the availability of higher tensile steels permitted the stressed skin and box girder designs to be accepted with increased efficiency in the application of materials. Specifications based on factors of safety were developed still more recently in place of the former 'factors of ignorance', but today such overall factors are giving way to the concept of partial factors using the limit state principle of design. The limit state method uses the computer to analyse the effects of stresses due to loading in combination with the other facets involved, the characteristics of the working environment over the projected lifespan of the artefact and fabrication procedures including workmanship imperfections. Thus, greater precision becomes possible which makes it still more essential to have and to understand all possible information on materials that is relevant to the design. Alongside such new design concepts and the research on which they are based, there have been many new materials developed and better understanding of properties of the old and the new. Engineers and the industries they serve tend to accept many of the results of research much too slowly but the need to save material through design is at last in the forefront of thinking on design. That it is a long drawn out operation is seen from many examples: thus, the plastic theory of design was developed by Sir John Baker more than a generation ago but is still not fully accepted as standard practice. It may well be asked how is the mass of new information to be taught? How is it to be assimilated? What must be taught to engineers not only at the undergraduate level but on a continuing basis through a professional career? These are only a few
of the many questions requiring answers which must be based on positive thinking and which must also be related to the needs of different parts of the world and of individual countries. The principles are of universal application but space permits only a discussion of the position in the UK. There is no doubt that all engineers from ONC technicians to post doctoral consultants require full quantified information about all properties as well as reliable data on the effects of fabrication and service conditions on these properties, taking account of wear, corrosion, fatigue, creep, the characteristics of fracture, effects of temperature, etc. Modern engineering requires that all engineers should take their responsibility seriously in using up to date information effectively. Engineering education, it was felt, may not have kept pace with the best means of using available data and some two years ago the Council of Engineering Institutions together with the Design Council asked the Institution of Metallurgists for help in considering this problem. The Design Council had previously published the findings of a Committee, chaired by MoultonJ which set out the requirements for educating industrial designers but with the deliberate omission of r e c o m m e n d a t i o n s on materials as they demanded specialist attention. After a series of meetings a report was published2 and subsequently the Fellowship of Engineering issued its own statement.3 These documents confirmed the need for new thinking, defined the problems and made certain recommendations. However, the discussions made it clear that there is no universal solution even when the problems have been analysed. Two distinct requirements emerged, however, the first emphasising the design stage and the second raising matters concerned with production, whilst economic factors were common to both.
The engineer's responsibilities Education of engineers in materials must be considered with respect to the responsibilities undertaken at three principal levels which can be readily defined by referring to the grades recognised by the Council of Engineering Institutions for registration through the Engineers' Registration Board. The Chartered Engineer (CEng) is competent by virtue of his fundamental education, training and experience to apply the scientific method and outlook to the analysis and solution of
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engineering problems, with personal responsibility in research ~md design, in m a n u f a c t u r e and c o n s t r u c t i o n , in management and in education. His work is predominantly intellectual and requires the exercise of original thought, plus the ability to supervise the work of others, both technically and administratively. By his education he is able to follow progress in his branch of engineering and to apply new knowledge independently, thus making contributions to the development of e n g i n e e r i n g science and its applications. The Chartered Engineer who must be a corporate member of the professional institution relevant to his knowledge, is normally required to have an Honours degree and must have undergone periods of training and experience. He is the spearhead of engineering in industry. The Technician Engineer (Tech.Eng.) is competent through his education, training and experience to exercise indep e n d e n t t e c h n i c a l j u d g m e n t in engineering, with personal responsibility for duties in his field. He understands the reasons for and the purpose of operations within his responsibility. He undertakes technical work of an established or of novel character either independently or under the direction of a Chartered Engineer, and he is able to lead. He must also bea corporate member of the appropriate professional institution and his minimum qualification is the HNC or HND or CGLI Full Technologist Certificate, though often he is a graduate. The Technician (Tech.) is able through his education, practical training and experience to apply proven techniques or procedures, with a measure of responsibility under the guidance of a Chartered Engineer or Technician Engineer. He must be able to communicate clearly and must be the holder of an ONC or CGLI Part2 certificate, as well as being a member of the relevam institution. In future, technicians and many technician engineers will be educated largely in colleges through the modules and prorammes validated by the Technician Education Council instead of the CGLI, ONC, HNC and HND schemes which are being phased out as they are replaced by TEC routes. Today there are 16 Corporation and 7 Affiliate Members of the Council of Engineering Institutions, with some 40 institutions registered with Technician Engineer or Technician Boards, representing in total about 200 000 individuals. Some ten thousand new graduates qualify in engineering and technology
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each year from British universities and polytechnics, with rather smaller numbers taking examinations which can lead to the professional qualifications of Tech.Eng. and Tech. It may be noted that it is a requirement of the CEI that its m e m b e r institutions provide Chartered Engineers, Technician Engineers and Technicians with a journal and other publications to enable them to maintain an interest and keep up to date. in their professional r e q u i r e m e n t s , including new materials and techniques. It should be part of the remit of the engineering institutions to publish relevant data on materials as they become available, on new uses of well known materials, and the overall economics of materials selection, as well as drawing attention to research affecting materials usage. For the exercise of their responsibilities all these new entrants to the profession require sound knowledge of materials and their uses, but the young engineer cannot possibly learn all that he requires to know about materials even at the start of his career. The basic principles and an a w a r e n e s s of the p r o b l e m s would probably be the most that could be inculcated, but industrial training should include an additional content of materials related to i h e j o b function. The modes of failure in service and the causes of difficulties in production provide many opportunities for furthering knowledge of. and interest in, materials. Clearly teaching requirements must be based on close collaboration between the design and production functions of e n g i n e e r i n g d e p a r t m e n t s a n d the corresponding departments concerned p r i m a r i l y with m e t a l s a n d o t h e r m a t e r i a l s . W h e r e s a t i s f a c t o r y cooperation exists the resulting graduates have excellent a p p r e c i a t i o n of the problems of materials but in some areas it is clear that certain courses are less integrated. As m a n y decisions on materials are taken in practice by technicians it is unfortunate that there appears to be relatively less attention to this topic than is desirable. Design procedures It is not easy to set down the design procedures in industry or to identify the point at which decisions on materials are made. Major capital projects, such as an oil refinery or a new fully equipped factory, are the result of design work by a t e a m of specialists able to include, or call upon, experts in related disciplines, and the team should have available the services of a metallurgist or materials
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engineer. At the other end of the scale, the small firm making a relatively few assemblies may not have anyone responsible for material decisions, and even c o m p a n i e s m a n u f a c t u r i n g for the consumer market may employ only a single person to design a product, select materials and get it into production. In these cases reliable information at the design stage and later, during production, is essential from independent experts or suppliers. It would be an impossible task to analyse and determine where decision making on materials actually occurs in practice. The initial concept for the production of a piece of equipment for general sale may be a d e m a n d from the Marketing Division of a large c o m p a n y or the result of an 'imagineering'creator. From this concept designs are fixed, first on paper and then as prototypes. At some point materials are selected, but this is often determined in the Drawing Office by a technician. This choice is then subject to change as a result of tests or through the d e m a n d s of production management or by economic factors through the purchaser office. It is often evident that the final selection of material has not been the decision of a design team, or even of a chief designer, and many case studies show the need for not only the education of engineers and technicians but also production management and purchasing officers in how to handle their respective functions responsibly and knowledgeably in concert with the materials engineer and the supplier. Too often the metallurgist is placed in the same p o s i t i o n as the m o r b i d pathologist to investigate and pronounce on the cause of failure rather than being consulted or, better still, being part of the team responsible for a product from its conceptual design through the prototype stage and its testing to final production and sale to satisfied customers. Many examples could illustrate the need for cooperation in detailed design and continually t h r o u g h o u t the p r o d u c t i o n sequence. Thus, drawings should invariably carry the correct, up to date reference to the material, preferably specified in terms of a British Standard instead of the still too c o m m o n reference to such non-informative words as "AI" or 'Alum" or 'Cast Aluminium" or "Cast Brass' the list is endless. Even when a correct specification reference is given on a drawing it is often qualified by the addition of "commercial grade' which appears to indicate, in the mind of the decision maker, that it is not worth paying for the correct material backed by
quality assurance and relevant testing. It is easy to go even further down such roads to failure as when the product properly designed with specified materials is virtually redesigned in the Purchase Office in order to save odd pence without reference back. It may not be realised that when ordering, for example, "commercial grade l,G4' the purchaser is asking for a leaded gunmetal casting to a nominal composition only, with little attention to the level of impurity content and without the benefit of melt quality tests or any Certificate of Compliance as required by the General Clauses of BSI400. This S t a n d a r d includes also a code to cover the means of inspection available to the purchaser and indeed draws attention to the desirability of including on the order the appropriate coding to determine whether radiographic or other tests are necessary in relation to the actual application. In general, m a j o r decisions on materials should not be, and probably are not, taken by newly qualified engineers or technicians without reference to higher authority, but sometimes senior staff may not be as fully informed a b o u t new materials or new developments in fabricating techniques as those with more recent training. W h a t should be taught? This is not an attempt at syllabus building or even of stating 'learning objectives', all of which are the subject of much debate, resulting in as many d o c u m e n t s as there are Departments of Engineering in their many forms and at various levels from O N C to higher degrees. Perhaps the most useful first point to be emphasised at all student levels is the interdisciplinary nature of materials studies in relation to design and production. The decreasing availability and increasing costs of materials bring this home to engineers in industry, a n d the c o m p l e x i t i e s in materials selection require explanation from the outset of every course. Teachers s h o u l d p r o v i d e an i n t e g r a t e d and coherent materials content t h r o u g h o u t each course, varying in emphasis and depth according to the level from technician to postgraduate. The engineer requires p r i m a r i l y quantified properties on a uniform basis covering all the materials he is likely (or even unlikely) to use in practice to meet the demands of production and service. but he is usually given, and often uses, only the figures based on standard specifications. These are confined to tensile strength, with yield point or p r o o f stress m i n i m a , some i n d i c a t i o n of
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ductility usually in the form of elongation as a percentage of gauge length and, perhaps. hardness, but these are no more than the minimum required by standardised tests for quality control purposes. Certainly in the case of cast metals, they may bear little relation to the strength properties of actual castings due to the important influence of such factors as the section thickness, the rate of cooling, the absence of porosity and variations from skin to core. The designer must be able to assess the need for. and to use. information on the modes of failure by steady stressing, impact loading and fatigue including notch sensitivity, creep and corrosion. Numerical data require much time and effort for their determination and interpretation. Other attributes which may require special testing are bearing characteristics, wear resistance and the combination of stressing and chemical attack known as stress corrosion. The effects of temperature are of increasing importance not only when these are significantly above or below ambient but also within the ranges n o r m a l l y encountered in every-day environments, such as the winter climate of the North Sea which can result in brittle fracture, or the slightly raised temperatures of electrical equipment which could lead to failure by creep. The production engineer requires data on machining, cold working limits, temperature ranges for forgingand stamping, weldability by various processes and finishing operations (which, being last in the manufacturing sequence, are often the source of trouble and delay). Information should be numerically oriented though there are limitations to the extent to which this is possible. The effect of fabrication on properties is often but little understood especially when welding is considered. The heataffected zone is probably that part of the cross-section of a weld that is most subject to defects and hence fraught with dangers. On metal that has been strengthened by cold working, this zone is inevitably softened as it is also in precipitation-hardened alloys. In the case of steels, it may well show great reductions in ductility and increases in hardness. It may also exhibit serious reductions in corrosion resistance due to partial melting or the segregation of alloying elements or impurities. Hence there is a need for at least an appreciation of the effects of working, heat treatment and fabrication operations on properties. Corrosion and protection are particularly interesting topics especially as
increasing attention is now given to reducing the need for maintenance with its high labour content. The study in depth of corrosion phenomena does not fall within the province of the engineer but means of reducing corrosion require an appreciation of the background in order that the precautions taken can be properly understood. An introduction to the electrochemical basis of corrosion is thus desirable and an engineer with "A" level knowledge of physics a n d / o r chemistry should well cope with this. Perhaps it suffices for the engineer to be aware of the problems, coupled with the need to consult the metallurgist/corrosion technologist, and to supplement this by the recently published Design Guide and the BSI Commentary on Bimetallic Corrosion. 4 It is becoming more widely accepted that the cost of a metal or an alloy, a composite or a non-metallic material should be ta ken into account as another property at the design stage but this is not easy because metal prices fluctuate over quite short periods. They may change significantly between the drawing board and prototype, as well as in later stages of production, and whilst the trend is generally upwards, there are times when substantial variations occur in the relative costs of competitive materials within short periods. It is more difficult to make due allowance for factors of availability and price than for alterations in mechanical properties which are less likely to occur hence the need to be aware of the need again to consult the materials expert who at least should be able to offer advice on likely trends. The basis of using the cost of each unit of tensile strength (or yield stress) has been well outlined by W. O. Alexander 5 and in due course may be accepted more widely, together with consideration of the energy content of a material. When decisions are being taken on the content of appropriate lecture courses, it is often easier to consider what is not required by the engineer. Thus, the production of metals from their ores or the manufacture of polymers from mineral oils or vegetables and animal sources can be taken as unnecessary, even though the engineer is rightly involved with the plant required for the processes concerned. It would also be agreed that the engineer's syllabus need not include alloy theory as propounded by Hume-Rothery of the Oxford School or G. V. Raynor or other specialists in metal physics and this side of physical metallurgy. The full treatment of crystallography and of dislocation theory are again beyond the scope of
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engineering courses but they impinge on design and production in such matters as notch sensitivity and fracture mechanics. The engineer should be aware that trace elements may have an important affect on engineering properties but again he need not be concerned with the minutiae of the reasons for their effects. Unwanted i m p u r i t i e s a n d , indeed, d e l i b e r a t e additions of trace elements are controlled in accordance with British Standards produced by expert Technical Comm i t t e e s on w h i c h the m a t e r i a l engineer~ ,metallurgist takes responsibility for setting limits. It is however desirable to avoid the development of anything akin to the "mysteries" of the ancient Guilds and the properly developed course with an integrated teaching staff can readily avoid this risk by covering selected facets of metallurgy based on the results of a major research programme. Many examples can be cited as suitable for such treatment and mention may be made of the current position of structural steels required for modern welding procedures. Steel technology has made such significant advances in the last 12-15 years that it is not surprising some engineers feel unable to differentiate between the uses of various grades offered by the steelmaker. Furthermore, it may be unfair to expect them to do so in the absence of reasonably simplified guides to the purpose of the alloying e l e m e n t s a d d e d to give specific properties. Modern steelmaking permits the ready production of virtually tailormade steels to fit the requirements of strength, impact properties at low temperatures, forming and weldability. Detailed studies have shown the effects of carbon and manganese contents to give optimum yield strength and toughness, combined with control of grain size by alloying addition of niobium and vanadium, related to rolling and heat treatment conditions. The range of steels for structural purposes has been stabilised and should facilitate teaching in engineering departments concerned with the design of those structures which account for a high proportion of steel usage today. Their potential benefits can be exploited, however, only by basing designs on yield strength and taking advantage of their good welding properties and ready formability. For their effective application it would be desirable for the graduate engineer to have sufficient understanding of the basic metallurgy of steel to enable him to appreciate the need for care in selection and precautions in use. Thus, the
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problem of hydrogen cracking in welded steels should be touched upon but again without including the full knowledge required by the welding engineer or metallurgist responsible for specifying the procedures covered in detail in a Welding Institute handbook. 6 Likewise the types of stainless steel should be outlined including their corrosion resisting and working properties, with particular attention to the need for minor alloying.elements to stabilise the structure of the steel when it is welded. This is a comparatively simple teaching task, but consideration of the non-ferrous metals and their multitudinous alloys is much more formidable. Copper is used commercially in about ten grades and its alloys are covered by well over 100 British Standards, whilst aluminium and its alloys require some 40 General Purpose Specifications in the UK with others for aircraft applications. When magnesium, nickel, tin, lead and zinc are added to the list they bring total British Standards to more than 200 and then there are the metals and alloys not the subject of specifications. Many of the non-metallic engineering materials are not covered by British Standards and data must be obtained from suppliers, other sources or specialists. Thus only an outline of these ranges of niaterials can be given in the available teaching time and this must include references to sources of information. Sources of i n f o r m a t i o n
The means of obtaining information have increased in scope and speed but many technologists appear to receive little training in using either the old or the new methods of data retrieval. The rapidly developing computerised procedures, based on key words and a standard thesaurus, require expert tuition for their efficient use - not least on how to pose questions to give the information needed. They are not, at present, an effective alternative to first hand acquaintance with tabulated data or with the original literature. Courses for technicians and engineers should therefore include not only an e~ement of how to use sources of data but also encouragement to at least scan preferably study original material. There has been a great deal said (and .accepted) about the need for engineers to be numerate but they must enjoy being literate! The various engineering handbooks published commercially, such as the well known Kempes or the more specialised ones devoted to specific industries, provide useful initial guidance but are not
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invariably up to date. The resources of the Research Associations are generally excellent in their own and related fields but new data in research reports and theses are not always readily available. Reference libraries are usually nonspecialist except when they belong to a professional institution or learned society. Major consultants maintain their own data banks and the largest industrial companies are able to service their designers and engineers through their own information departments. Other sources of readily usable data include the Fulmer Materials Optimiser 7 and the series of Design Guides ~ to which additions are still being made. The educators must teach how such information aids should be used and also how computerised data banks should be approached to yield appropriate answers to questions posed by engineers. The education and training of a designer should make him capable of'digging" for information for "special requirements'. A particularly important topic to be covered in an undergraduate course or a short course for in-career education is the use of British Standards - the specifications of other countries and the ISO including the value of the data and advice given in some of them as Appendices or Guidance Notes "For Information Only'. Thus, again referring to BSI400, the thirty alloys listed therein are divided into three groups, A, B and C, of which the first are the twelve alloys in common use and hence available more readily and at lower prices than those in groups B and C useful commercial guidance not always considered to be appropriate to, or available in, a Standard. Likewise, there is essential information in many of the standards for welding consumables which should be included on drawings and purchase requirements. Therefore the correct use of British Standards is an essential part of education which often becomes apparent only later when failures have been the result of lack of understanding- leading to legal actions if not inquests! The teacher at every level should have had first hand experience of the problem of finding readily usable design data and so be able to illustrate his themes by personal examples. This leads to considering the means by which actual industrial experience in the various design fields can be brought to bear in educational establishments, in addition to academic staff making and renewing their own contacts with manufacturing concerns. Visiting professorships could be more often arranged, lectures by part
time staff from industry or consulting organisations are of value and the study of case histories provide particularly useful lessons. C a s e studies
The presentation and discussion of ease studies is one of the most rewarding m e a n s of t e a c h i n g e n g i n e e r s the importance of materials selection taking account of fabrication, economics and quality assurance aspects. It is, however, not easy to obtain detailed accounts of how decisions were arrived at, how judgement had been exercised and how much part was played by experience which is often difficult to pin down, let alone quantify. It is difficult to obtain reliable information from either industrial successes or from the investigation of failures because of commercial considerations and the risks of disclosure of useful i n f o r m a t i o n to c o m p e t i t o r s . Case histories of failures are perhaps easier to obtain providing that anonymity can be preserved. It is significant that the British Case Study Clearing House at the Cranfield I n s t i t u t e of T e c h n o l o g y is being developed to cover engineering topics and this may well provide new bases for teaching. The c o o p e r a t i o n of professional institutions can help to make such information available from their individual merribers, and the assistance of Research Associations should also be sought. Direct industrial experience of teachers in universities and polytechnics is an important factor in success, and should be supplemented by lecturers from industry or consulting firms. A specific point to be made concerns the need to test prototypes and production models to destruction and to relate the results to the input of data at each stage. Lessons learned and applied provide valuable case study material and if such testing and checking of prototypes (or early production models) can be undertaken in university or college laboratories an air of reality can be given to lectures and tutorials which may otherwise appear to students to be too remote from an industrial job.
Progress It may well be argued that such a full and varied content must lead inevitably to longer courses with engineering undergraduates requiring four instead of three years to first degree level or the option of a further year for a taught MSc to cover materials in the depth required by the designer in today's industries. The content of any specific course must be
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decided only after close consultation with industry to ensure that too much theory is not included at the expense of practical engineering experience. Industries differ in their approach to sophistication in design and there are major variations between sectors such as aeronautical engineering and shipbuilding. Some sectors are conscious of value engineering, some aim for minimum maintenance over long periods, some rely on large factors of safety - the designer cannot be expected to become expert in all the variants. Hence, industry must provide facilities for training, as well as advise on course contents, for the design engineer and industrial designers whom it hopes to employ. Many academics advocate concentration on materials in postgraduate courses and a particularly valuable example is provided by the Cranfield Institute of Technology which recently created a Centre of Engineering Design where special attention is inevitably paid to materials selection. In the last few years valuable initiatives have emerged at a number of universities: for example, at Bradford two main courses, one in mechanical engineering design and one based on manufacturing design, have a common sector for materials and these sandwich-based courses provided valuable practical experience of materials throughout the four-year period involved. Likewise at Sheffield, Southampton and Bath there have been new approaches at undergraduate level and at Imperial College in London an MSc course in Design ran alongside a Master of Design course in association with the Royal College of
Design. The industrial designer is essentially aesthetic in his approach and may pursue such associated topics as ergonomics. The more numerate engineering designer is concerned with analysing a problem mathematically leading to designs which depend on accurate data on the properties of materials. In all engineering design a knowledge of materials is essential but specific quantitative data require also experience in their use and the ability to obtain the cooperation of the materials specialist, particularly where depth of knowledge is required, such as on brittle fracture. In some University Civil Engineering Departments, I0% of undergraduate time may be devoted to materials but the proportion tends to be lower in other engineering disciplines. Usually teaching is best done by specialists from the metallurgical or materials science departments but close cooperation between departments is essential and there are many opportunities for improvement in this. A joint effort might bring to fruition a scheme to help teachers through the professional institutions most directly concerned - the metallurgists with the mechanical and production engineers -. to provide a service on materials in manufacturing industries for use by the engineering designer and production engineer. Whilst the case has been made for the undergraduate going into engineering to have knowledge of materials and early experience in their use, it is just as important for the metallurgist/materials specialist to be aware of the basic principles of design so that he is able to appreciate the problems encountered by
the designer. To each side c o m munication of knowledge is obviously essential and calls for each to understand the accepted terminology be it words. mathematical formulae, drawings or a computer print out. It must be appreciated that an engineer with a veneer of materials knowledge is of no more value than a metallurgist with a smattering of engineering. Acknowledgement is gladly given to the many friends who have given their views at various times and to those who attended the meetings which led to the reports mentioned in this article. References I. Engineering
Design Education. Design Council 1976 Report on current education of engineering designers. 2. Report on "Education of Design Engineers and Industrial Designers in the Use of Materials" submitted to the Design Council. July 1977: The Metallurgist & Materials Techmthtgist. Jan. 1978. 3. Report on 'Education of Engineers and Technicians in Relation to Materials', Nov. 1978. published by the Fellowship of Engineering. London SWI. price £1.50. 4. Metal Corrosion, T. K. Ross. Oxford University Press, No. 21, 1977 PD6484:1979 Commentarr on Corrosion at Bimetallic Contacts and its Allet'iation. BSI. London 5
WI. For example, W.O. Alexander and P. M. Appoo. Metals & Materials. July/August 1976, pp42-45.
6. Welding Steels Without Hydrogen Cracking. F.R. Coe, Welding Institute publi-
cation 1973, 68 pp. Materials Oplimiser. Fulmer Research Institute, Stoke Poges. Bucks. SL24QD. 8. Engineering Design Guides, Design Centre. 28 H a y m a r k e t , London SWIY 4S U. and Oxford University Press. 7. Fulmer
International Conference "The implication of materials selection on product liability" The proceedings of this conference held in September 1979 will be published by Scientific & Technical Press and will be available early in 1980 price £25. The following papers will be presented: I. The current and potential l e p l requirements for product liability in UK, Europe and USA. B. D. Monk. MBG Management Consultants Ltd. 2. Product faaum due to bad material choice and processing. N~ A. Waterman, Fulmer Reseurch Institute. 3. Safety in chemical proce~ plant. C. Edeleanu, Cambridge Univerztty. 4. The implications of equipment materials selection on product liabifity in food processing. C. D. Marriott. Unilever Research Laboratory, Colworth House, Bedford. 5, Product quality, product liability and oil products, R. Lindsay, Shell UK Ltd. 6. Testing for product liability.D.B.S. Berry. Yarrley Technical Centre. ]'rowers Way, RedhiU, Surrey. 7. Materiels selection for durability. P. Watson. GKN Group Technology Centre. Birmingham New Road, Wolverhampton.
MATERIALS IN ENGINEERING APPLICATIONS. Vol. 1. September 1979
8. Materials used in manufacture of consumer goods. D. J. Unwin. Consumers" Associntion, Research Division Laboratories, Harpenden Rise Laboratory, Harpenden, Harts. 9. D,I.Y. Products. A. Treadwell, Black and Decker liraland) Ltd., Naa$, Republic o f Ireland. I0, Elastomer ageing and product liability.J.N. Ha~rsand D. Norbury, Dunlop Ltd., Research Centre, Kinglbury Road, Birmingham. I I, Contribution of condition monitoring to the elimination of failure in service. M. J. Neale, Michael Neale & Associates, 43 Downing Street, Farnham, Surrey. 12. The insunmce of product liability. P. Sherman, Royal Insurance Company Ltd., t>.(2. Box 144, New Hull Place, Liverpool,
Orders to Scientific and Technical Press, Chilbcrton Holtle. Doods Road, Reigate. Surrey, England - Tel: Relgate (07372) 43521.
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