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High performance wrought PM tool steels
Automotive parts FAILURE MODES AND ANALYTICAL TECHNIQUES FOR PM GEARS T.Prucher, H.Sanderow. (Management and Engineering Technologies, Inc, USA.) Gear failure was discussed and three modes of failure were identified: tooth fracture, contact fatigue failure and failure by wear. These were examined for mechanisms causing failure, operating regimes where failure occurs and methods for avoidance of failure. Test programmes were described. Analytical methods for prediction of gear response were reviewed. Comparison was made between PM and cast/wrought steel gears. ROLLING CONTACT FATIGUE AND STRUCTURE/PROPERTY RELATIONS IN A CARBON-MOLYBDENUMSTEEL D.S.Lashmore, S.Kaiser. (Materials Innovation, USA.) It was reported that high strength MO-Csteels, pressed to 7.3 g.cmM3 and sintered to 7.5 g.cmm3,had been developed. The steel exhibited a wide range of properties, such as Rockwell hardness from 60B to 60°C and dimensional change of 0 to 1.1% , with some anisotropy. Data for contact fatigue behaviour, rolling mechanical properties and structures were presented. AERATION POWDER FILLING FOR HIGH PERFORMANCE PM PARTS K.Nakatani. (Toyota Motor Corp, Japan.1 The importance of powder characteristics for uniform die filling and powder compaction was discussed. It was reported that a powder aeration technique had been used to aid uniform die filling by improving powder flow properties. This also reduced scatter in properties. Process efficiency, cost reductions and improvement in pore distribution were outlined. PRECISION COLD FORGING OF A PM PREFORM TO MARE A HIGH DENSITY SPUR GEAR H.Ferguson. (Metal Powder Products Co, USA.) Design and manufacture of a 17tooth spur gear by cold forging a powder preform to 96% density were described. The powder forged part was to replace a machined gear in a tractor transmission system.
Demand from automotive makers for materials with improved rolling contact fatigue resistance and high toughness was noted. It was reported that parts with densities up to 7.6 g.cme3had been made by a single press-and-sinter route. This gave high rolling contact fatigue resistance. Some properties and automotive application were described.
Fully dense PM products GAS ATOMIZATION J.S.Dunkley. (Atomising Systems Ltd, UK.) It was noted that while gas atomization is widely used for powder production it remains an empirical technology. Techniques in use were described and discussed. Speculations were presented concerning future developements. Improvements in efficiency and reductions in costs were considered. Hyperbaric atomization for production of ultrafine powders was reviewed. A STUDY OF A PRODUCTION GAS ATOMIZER J.J.Conway et at. (Crucible Compaction Metals, USA.) A computer study of the gas-only flow field in close coupled gas atomization, for a range of variables, with respect to efficiency, increased yield of fine powder and operating costs, was described. The study was validated using a production atomizer. It was reported that costs had been reduced in full scale production trials. AN OPERATOR’S VIEW OF HOT ISOSTATIC PRESSING E.J.Tenerini. (Bodycote IMT, Inc, USA.) Expansion of the scale of HIP operations since its introduction were outlined with reference to the range of possible applications. Operational aspects of medium to large HIP installations were reviewed. Some misconceptions concerning HIP were discussed. HIP CLAD ALLOYS FOR CRITICAL APPLICATIONS M.F.Bishop, C.K.Nickel. (Crucible Compaction Metals Inc, USA. It was reported that HIP had been used to clad a low alloy material with a high alloy. The emphasis of the paper was on applications in severe service conditions such as are encountered in plastics extrusion machinery.
DEVELOPMENT AND APPLICATIONS OF HIGH DENSITY COLD COMPACTION
HIGH PERFORMANCE WROUGIIT PM TOOL STEELS
P.Blanchard. (Federal Mogul Sintered Products, France.1
R.B.Dixon. (Crucible Research, USA.) Production of full density high per
48 MPR November 2000
formance tool steels from prealloyed powders by HIP and hot working was outlined. Some examples, including recent developments, were presented.
Cemented
carbides
MICROSTRUCTURAL DEVELOPMENT DURING MICROWAVE SINTERING OF CEMENTED TUNGSTEN CARBIDE R.L.Eadie et al. (University of Alberta, Canada.) It was reported that microwave sintering had been used for a variety of carbide powders in a range of particle sizes. Structures of the materials, some sucessfully sintered, were characterized. The test results were shown to demonstrate advantages for microwave sintering of carbides and were discussed with reference to new models for sintering. SOLID STATE SINTERING OF CEMENTED CARBIDES UNDER ELECTRIC FIELD APPLICATION MKramer et al. (University of California, Davis, USA.) It was reported that the application of an electric field enhanced solid state sintering of WC-Co. Conventional sintering reached 95% density for extra- or ultra-fine powders and 75 to 85% for fine and coarse powders prior to formation of the liquid phase. The effects of the electric field on solid state sintering of carbides were discussed.
Aluminium based MMCs PM PROCESSING AND CHARACTERISTICS OF DISCONTINUOUSLYREINFORCED ALUMINIUM C.A.Smith, A.Rapaport. (Aerospatiale, France.) It was reported that PM techniques had been used to fabricate Al alloy matrix composites reinforced with Sic particles for aerospace applications. Development of methods to make large billets was described with consideration of matrix/reinforcement relationships and material properties. Some applications were described with regard to alternative materials. ELECTRO-DISCHARGE CONSOLIDATION OF ALUMINIUM-ALUMINA COMPOSITES K.Ohtera et al. (YKK Corp, Japan.) It was reported that an AlAlsO, composite had been prepared by mechanical grinding the powders and consolidated by electro-discharge at high voltage and high current density. 93% density was attained. Surface oxide
Demand from automotive makers for materials with improved rolling contact fatigue resistance and high toughness was noted. It was reported that parts with densities up to 7.6 g.cme3had been made by a single press-and-sinter route. This gave high rolling contact fatigue resistance. Some properties and automotive application were described.
Fully dense PM products GAS ATOMIZATION J.S.Dunkley. (Atomising Systems Ltd, UK.) It was noted that while gas atomization is widely used for powder production it remains an empirical technology. Techniques in use were described and discussed. Speculations were presented concerning future developements. Improvements in efficiency and reductions in costs were considered. Hyperbaric atomization for production of ultrafine powders was reviewed. A STUDY OF A PRODUCTION GAS ATOMIZER J.J.Conway et at. (Crucible Compaction Metals, USA.) A computer study of the gas-only flow field in close coupled gas atomization, for a range of variables, with respect to efficiency, increased yield of fine powder and operating costs, was described. The study was validated using a production atomizer. It was reported that costs had been reduced in full scale production trials. AN OPERATOR’S VIEW OF HOT ISOSTATIC PRESSING E.J.Tenerini. (Bodycote IMT, Inc, USA.) Expansion of the scale of HIP operations since its introduction were outlined with reference to the range of possible applications. Operational aspects of medium to large HIP installations were reviewed. Some misconceptions concerning HIP were discussed. HIP CLAD ALLOYS FOR CRITICAL APPLICATIONS M.F.Bishop, C.K.Nickel. (Crucible Compaction Metals Inc, USA. It was reported that HIP had been used to clad a low alloy material with a high alloy. The emphasis of the paper was on applications in severe service conditions such as are encountered in plastics extrusion machinery.
DEVELOPMENT AND APPLICATIONS OF HIGH DENSITY COLD COMPACTION
HIGH PERFORMANCE WROUGIIT PM TOOL STEELS
P.Blanchard. (Federal Mogul Sintered Products, France.1
R.B.Dixon. (Crucible Research, USA.) Production of full density high per
48 MPR November 2000
formance tool steels from prealloyed powders by HIP and hot working was outlined. Some examples, including recent developments, were presented.
Cemented
carbides
MICROSTRUCTURAL DEVELOPMENT DURING MICROWAVE SINTERING OF CEMENTED TUNGSTEN CARBIDE R.L.Eadie et al. (University of Alberta, Canada.) It was reported that microwave sintering had been used for a variety of carbide powders in a range of particle sizes. Structures of the materials, some sucessfully sintered, were characterized. The test results were shown to demonstrate advantages for microwave sintering of carbides and were discussed with reference to new models for sintering. SOLID STATE SINTERING OF CEMENTED CARBIDES UNDER ELECTRIC FIELD APPLICATION MKramer et al. (University of California, Davis, USA.) It was reported that the application of an electric field enhanced solid state sintering of WC-Co. Conventional sintering reached 95% density for extra- or ultra-fine powders and 75 to 85% for fine and coarse powders prior to formation of the liquid phase. The effects of the electric field on solid state sintering of carbides were discussed.
Aluminium based MMCs PM PROCESSING AND CHARACTERISTICS OF DISCONTINUOUSLYREINFORCED ALUMINIUM C.A.Smith, A.Rapaport. (Aerospatiale, France.) It was reported that PM techniques had been used to fabricate Al alloy matrix composites reinforced with Sic particles for aerospace applications. Development of methods to make large billets was described with consideration of matrix/reinforcement relationships and material properties. Some applications were described with regard to alternative materials. ELECTRO-DISCHARGE CONSOLIDATION OF ALUMINIUM-ALUMINA COMPOSITES K.Ohtera et al. (YKK Corp, Japan.) It was reported that an AlAlsO, composite had been prepared by mechanical grinding the powders and consolidated by electro-discharge at high voltage and high current density. 93% density was attained. Surface oxide