Injection moulded composite materials

PM

better shape retention during thermal d e b i n d i n g . It w a s s u g g e s t e d t h a t t h e o p t i m u m b i n d e r m i x t u r e should contain more t h a n one polymer. VISCOSITY M E A S U R E M E N T OF POWDER I N J E C T I O N MOULDING (PIM) FEEDSTOCK M.Y. Cao et al, (Rensselaer Polytechnic Inst, Troy, New York, USA). Results of viscosity m e a s u r e m e n t s of t h e f e e d s t o c k for PIM w e r e r e p o r t e d . A capilliary r h e o m e t e r was used in which t h e material u n d e r t e s t is e x t r u d e d t h r o u g h a tube a n d p r e s s u r e is m e a s u r e d as a function of time until a steady state is r e a c h e d f r o m w h i c h t h e v i s c o s i t y is c a l c u l a t e d . F l u c t u a t i o n s in t h i s s t e a d y value of pressure revealed facts concerning t h e uniformity of t h e feedstock a n d the t e n d e n c y of t h e b i n d e r to s e p a r a t e from the powder. E x a m p l e s were given to illustrate t h e usefulness of t h e t e c h n i q u e in assessing t h e p r o c e s s i n g b e h a v i o u r of t h e PIM feedstock. D E S I G N A N D P R O C E S S I N G OF T E S T S P E C I M E N S FOR M E A S U R E M E N T OF MECHANICAL P R O P E R T I E S O F METAL INJECTION MOULDED (MIM) 4600 CARBON STEEL P.A. Hauck et al, (SSI Technologies Inc, Janesville, Wisconsin, USA). It was suggested t h a t t h e d e m a n d for p a r t s m a d e by MIM will increase in n u m b e r as new materials are developed a n d t h a t a barrier to this, lack of d a t a concerning mechanical properties, exists. A description was given of a modified t e s t piece which was used to assess MIM 4600 steels a n d of t h e steps needed to reach t h e required design.

MECHANICAL P R O P E R T I E S A N D MICROSTRUCTURES OF METAL I N J E C T I O N M O U L D E D ( M I M ) PARTS MADE WITH A NEW B I N D E R TECHNIQUE M. Bloemacher, (BASF AG, Ludwigshafen, Germany). A new MIM binder, which h a s s h o r t d e b i n d i n g t i m e s at low temperatures, h a s been developed. The t e m p e r a t u r e required is less t h a n t h e m e l t i n g p o i n t of t h e polymer used a n d this was found to help s h a p e r e t e n t i o n . The b e h a v i o u r of t h e b i n d e r system d u r i n g mixing, m o u l d i n g a n d d e b i n d i n g was r e p o r t e d t o g e t h e r with t h e m e c h a n i c a l properties of some tested materials. INJECTION MOULDED COMPOSITE MATERIALS J.R. Howell a n d A. Lawley, (Deere & Co, Moline, Illinois, USA). Injection moulding was applied to t h e p r o d u c t i o n of a complex s h a p e d m a c h i n e

LITERATURE

REVIEW

c o m p o n e n t which was i n t e n d e d to fracture in a brittle mode to prevent d a m a g e to the rest of t h e m a c h i n e in t h e event of a n accident. The c o m p o n e n t h a s a wrought steel s u b s t r a t e on to which a wear r e s i s t a n t coating is applied by injection moulding. Test pieces were p r e p a r e d from steel with the PM surface applied, a n d wear resistance and fracture properties evaluated. C o m p a r i s o n was m a d e with conventionally m a n u f a c t u r e d specimens. The results were discussed with regard to t h e properties a n d economic e n v i r o n m e n t a l considerations.

Technological Univ, Michigan, USA). An investigation into t h e effects of nonmetallic inclusions on the mechanical properties of steels powder forged to full density was described. It was r e p o r t e d that, d e p e n d i n g on inclusion, particle shape, size a n d d i s t r i b u t i o n , ductility a n d f r a c t u r e toughness are affected but strength properties are insensitive to t h e presence of inclusions. Microstructure a n d fracture s u r f a c e s w e r e e x a m i n e d by s c a n n i n g electron microscopy a n d all t h e results analysed statistically.

METAL I N J E C T I O N MOULDING ( M I M ) OF C E M E N T E D CARBIDES ON TO A 4 6 0 0 S T E E L SUBSTRATE

P R O P E R T I E S OF HIGH DENSITY POWDER F O R G E D 4 6 4 5 S T E E L CONTAINING M A N G A N E S E S U L P H I D E

K.M. Kulkarni a n d H.S. Meeks, (Advanced Metalworking Practices Inc, Carmel, Indiana, USA). The p a p e r r e p o r t e d a feasibility study of t h e injection moulding of WC-Co t o o t h caps on to 4600 steel for use in roller cone drill bits. The t o o t h caps were m a d e by MIM a n d b o n d e d to t h e steel body using t h e Ceracon process. The steel was s i m u l t a n e o u s l y densified. Low cost tooling was used for t h e MIM.

SJ. Mashl et al, (Michigan Technological Univ, Michigan, USA) The effects of MnS, up to 0.3wt%, in steel, powder forged to a density of 7.85 g / c m a or more a n d with less t h a n 0.2% porosity were investigated. The d e t r i m e n t a l effects of MnS were discussed in terms of the m i c r o s t r u c t u r e in pearlitic a n d t e m p e r e d m a r t e n s i t i c steel.

Powder forging and high density processing F U N D A M E N T A L S ON D E N S I F I C A T I O N DURING ROTARY COLD R E P R E S S I N G (RCR) G. Pregowski, (Rotapress I n t e r n a t i o n a l Inc, USA). RCP h a s been used to increase t h e d e g r e e of d e n s i f i c a t i o n of s i n t e r e d materials, a n d t h e process a n d results obtained on steels 4600 and 316L s t a i n l e s s w e r e d e s c r i b e d . RCP u s e s r e p e a t e d loading between dies of small regions of t h e work piece a n d a triaxial stress s t a t e exists. Hardness m e a s u r e m e n t s a n d ultrasonic tests were used to show t h a t d e n s i f i c a t i o n p r o c e e d s from t h e u p p e r r o t a t i n g die. APPLICATION OF POWDER FORGING TO AN A L U M I N I U M ALLOY D.W. S m i t h et al, (Michigan Technological Univ, Michigan, USA). I m p a c t powder forging was reviewed with respect to economics a n d properties of IPF materials. A p r o g r a m m e of work to assess these was described. Costs of IPF were modelled a n d found to be favourable. D e n s i t y a n d p r o p e r t y v a r i a t i o n s as a f u n c t i o n of IPF process v a r i a b l e s were described.

Quality planning and training QUALITY PLANNING G.T. Shturz, (Carbon City Products Inc, St Mary's, Pennsylvania, USA). T h e q u a l i t y of PM p r o d u c t s w a s discussed with p a r t i c u l a r regard to t h e r e l a t i o n s h i p b e t w e e n t h e m a k e r of PM p a r t s a n d t h e user. The i m p o r t a n c e of j o i n t p l a n n i n g of quality was stressed a n d it was suggested t h a t in t h e future quality clauses will f e a t u r e m o r e m a r k e d l y in supply contracts with much greater e m p h a s i s p l a c e d on quality. With t h e move towards more individual c o m p o n e n t s t h e r e will a l s o b e m o r e customized quality a g r e e m e n t s w h i c h will replace t h e s t a n d a r d i z e d supplier quality concepts. ANALYSIS OF C U S T O M E R R E Q U I R E M E N T S AND CORPORATE N E E D FOR QUALITY PLANNING I ~ _ D u n n i n g a n d G.E. Meek, (Univ of Akron, Ohio, USA). A t t e n t i o n was drawn to t h e fact t h a t buyers of PM a n d o t h e r p a r t s often audit their supplier's procedures for the m a i n t a i n a n c e of quality, a n d look to see progressive improvements in quality c o n t r o l , a s s u r a n c e a n d p l a n n i n g . The a p p r o a c h to quality is a t t h e initiative of t h e buyer who d e t e r m i n e s t h e level of quality. TRAINING FOR TOTAL QUALITY

INFLUENCE OF MICROSTRUCTURE ON PORE-FREE DENSITY OF POWDER F O R G E D STEEL D.W. S m i t h a n d SJ. Mashal,

(Michigan

E. Akpan, (Reliance Electric Co, Weaverville, North Carolina, USA). The role of the customer in i m p l e m e n t i n g a quality p r o g r a m m e a n d

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