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Corrosion of sintered metal parts
PM magnesium alloys K.U.Kainer, T.Ebert. (Technical University, Clausthal, Germany.) It was noted that the poor properties have limited the use of Mg and Mg alloys. It was shown that PM could be used in development of new Mg based materials making use of inert gas atomization, improved consolidation methods and powder spray forming. The new alloys had fine grain structures with uniform distribution of fine precipitates. Heat treatment gave further improvements. The potential of PM Mg was discussed.
Progress in application of sintered aluminium B.Hofmann er al. (GKN Sinter Metals GmbH, Radevormwald, Germany.) The need to reduce vehicle weight to reduce fuel consumption was discussed with reference to the use of A1. The presentation concentrated on replacement of grey cast iron and medium performance steels with A1 alloys by consideration of case studies.
Potential of metallic foams in lightweight structural automotive parts F.Simancik et al. (Slovak Academy of Sciences, Bratislava, Slovakia.) Use of PM to make net shape A1 foams was discussed with reference to applications and the ability to allow distribution of load bearing material to match loading conditions without increase in weight. Applications noted included impact energy absorption and noise reduction. Potential in automotive use was emphasized.
Use of metal injection moulding for manufacture of aero-engine parts M.Kraus, W.Smarsly. (Motoren u Turbinen Union Mgnchen, Germany.) Use of MIM for mass production of parts was discussed. It was reported that the feasibility of MIM for making aero-engine parts had been established with due regard to fatigue properties and cost reductions. Some of the alloys, such as Ni superalloys require advanced processing methods to ensure attainment of specified properties. Prototype parts had been made. Further work was required for aluminide materials.
Processing for high density High density components using elastic die technology G.Greetham. (Ipswich, Suffolk, UK.) The importance of high density for PM parts was discussed. It was noted that pressing to high density may lead to problems in tooling and ejection. A technique that allows the die to compensate elastically for elastic springback during ejection was described.
38
MPR September 2OOl
This was shown to allow low die wear and low ejection forces.
Powder forging of engine transmission parts U.Bode. (GKN Sinter Metals GmbH, Radevormwald, Germany.) Development of powder forging for production of automotive gear train and engine parts was reviewed. The technology includes compaction and forging in closed dies, with and without lateral flow of material, the object being to minimize costly machining, to make a part that is ready for assembly. It was suggested that new materials, with the ability to match properties to application requirements, will be developed.
Properties High cycle fatigue properties of PM steels B. Weiss, H.Danninger. (University of Vienna, Austria.) Relationships between fatigue properties of PM steel and structure, particularly porosity, isolated closed pores or interconnecting pores, were discussed. Interactions between structural features and crack initiation and propagation were considered. A fracture mechanics approach, to allow prediction of the effects of singular defects, pores and inclusions, on high cycle fatigue properties of high performance PM parts was proposed.
criteria of consistency and predictability. Examples were given from studies of failure of parts and how these can be improved.
Full density high speed steel valve seat inserts L.Farthing, P.Maulik. (Federal-Mogul Sintered Products, Ltd, UK.) It was reported that new approaches to pressed and sintered parts had led to products capable of replacing traditional cast parts. Developments based on full density M42 high speed steel, with modified composition, including incorporation of solid lubricants, for use as valve seats in heavy duty engines, were described. Processing was outlined and product properties discussed.
Material and design for improved performance of stainless steel exhaust flanges P.K.Samal et al. (OMG Americas, Research Triangle Park, USA.) Use of PM stainless steels in automotive exhaust systems was reviewed. PM was shown to confer advantages compared with cast/wrought methods of production in terms of material utilization, dimensional control and costs. PM ferritic stainless steels were shown to meet the requirements for exhaust flanges, particularly after modifications to design and material.
Wear of bronze with addition of nickel Corrosion of sintered metal parts A.Moiinari et al. (University of Trento, Italy.) Researches into corrosion protection of sintered parts by metallic coatings and corrosion resistance of stainless steel were described. Mechano-chemical corrosion was considered. For maximum corrosion resistance stainless steel requires maximum density, closed pores and freedom from grain boundary precipitated carbides and nitrides. Some alternative solutions were suggested. For steels with less corrosion resistance the strategies have been paint or metallic coatings applied by electrodeposition, hot dipping or metal spraying. The presence of porosity requires care in preparation for electrodeposition. Possible entrapment in pores means that aggressive solutions should be avoided. Zn and Ni plating were considered.
Applications Sintered parts in motor vehicle transmissions S.Hock, U.Baum. (ZF Friedrichshafen, Germany.) It was suggested that motor vehicle transmissions will change. This will not affect the scope for use of PM parts and may lead to increased use of sintered materials that satisfy
P.Sanchez et al. (PolytechnicUniversity of Madrid, Spain.) Cu-10%Sn powders, with and without additions of graphite or Ni coated graphite powder, were pressed and sintered in N-H. The alloys with Ni were heat treated to age harden. Pin-on-disc tests were carried out to evaluate wear and friction properties. Wear damage was assessed by scanning electron microscopy.
PM materials for synchronizer rings M.Krehl, R.Rau. (Sinterstahl GmbH, F~ssen, Germany.) The requirements of synchronizer rings in automotive transmissions were identified as generation of friction and torque for synchronizing, high wear resistance and high strength and toughness. Materials used have included forged brass, forged steel and PM steel. Materials for PM parts were discussed in terms of properties and costs.
Sinter hardening for production of transfer case sprocket M.Gagn~et al. (Quebec Metal Powders, Canada.) Sinter hardening of steel parts was reviewed with regard to methods and materials and the ability to make parts that may be difficult to quench due to size and/or shape. It was reported that sinter hardening had been used
www.metal-powder.net
Progress in application of sintered aluminium B.Hofmann er al. (GKN Sinter Metals GmbH, Radevormwald, Germany.) The need to reduce vehicle weight to reduce fuel consumption was discussed with reference to the use of A1. The presentation concentrated on replacement of grey cast iron and medium performance steels with A1 alloys by consideration of case studies.
Potential of metallic foams in lightweight structural automotive parts F.Simancik et al. (Slovak Academy of Sciences, Bratislava, Slovakia.) Use of PM to make net shape A1 foams was discussed with reference to applications and the ability to allow distribution of load bearing material to match loading conditions without increase in weight. Applications noted included impact energy absorption and noise reduction. Potential in automotive use was emphasized.
Use of metal injection moulding for manufacture of aero-engine parts M.Kraus, W.Smarsly. (Motoren u Turbinen Union Mgnchen, Germany.) Use of MIM for mass production of parts was discussed. It was reported that the feasibility of MIM for making aero-engine parts had been established with due regard to fatigue properties and cost reductions. Some of the alloys, such as Ni superalloys require advanced processing methods to ensure attainment of specified properties. Prototype parts had been made. Further work was required for aluminide materials.
Processing for high density High density components using elastic die technology G.Greetham. (Ipswich, Suffolk, UK.) The importance of high density for PM parts was discussed. It was noted that pressing to high density may lead to problems in tooling and ejection. A technique that allows the die to compensate elastically for elastic springback during ejection was described.
38
MPR September 2OOl
This was shown to allow low die wear and low ejection forces.
Powder forging of engine transmission parts U.Bode. (GKN Sinter Metals GmbH, Radevormwald, Germany.) Development of powder forging for production of automotive gear train and engine parts was reviewed. The technology includes compaction and forging in closed dies, with and without lateral flow of material, the object being to minimize costly machining, to make a part that is ready for assembly. It was suggested that new materials, with the ability to match properties to application requirements, will be developed.
Properties High cycle fatigue properties of PM steels B. Weiss, H.Danninger. (University of Vienna, Austria.) Relationships between fatigue properties of PM steel and structure, particularly porosity, isolated closed pores or interconnecting pores, were discussed. Interactions between structural features and crack initiation and propagation were considered. A fracture mechanics approach, to allow prediction of the effects of singular defects, pores and inclusions, on high cycle fatigue properties of high performance PM parts was proposed.
criteria of consistency and predictability. Examples were given from studies of failure of parts and how these can be improved.
Full density high speed steel valve seat inserts L.Farthing, P.Maulik. (Federal-Mogul Sintered Products, Ltd, UK.) It was reported that new approaches to pressed and sintered parts had led to products capable of replacing traditional cast parts. Developments based on full density M42 high speed steel, with modified composition, including incorporation of solid lubricants, for use as valve seats in heavy duty engines, were described. Processing was outlined and product properties discussed.
Material and design for improved performance of stainless steel exhaust flanges P.K.Samal et al. (OMG Americas, Research Triangle Park, USA.) Use of PM stainless steels in automotive exhaust systems was reviewed. PM was shown to confer advantages compared with cast/wrought methods of production in terms of material utilization, dimensional control and costs. PM ferritic stainless steels were shown to meet the requirements for exhaust flanges, particularly after modifications to design and material.
Wear of bronze with addition of nickel Corrosion of sintered metal parts A.Moiinari et al. (University of Trento, Italy.) Researches into corrosion protection of sintered parts by metallic coatings and corrosion resistance of stainless steel were described. Mechano-chemical corrosion was considered. For maximum corrosion resistance stainless steel requires maximum density, closed pores and freedom from grain boundary precipitated carbides and nitrides. Some alternative solutions were suggested. For steels with less corrosion resistance the strategies have been paint or metallic coatings applied by electrodeposition, hot dipping or metal spraying. The presence of porosity requires care in preparation for electrodeposition. Possible entrapment in pores means that aggressive solutions should be avoided. Zn and Ni plating were considered.
Applications Sintered parts in motor vehicle transmissions S.Hock, U.Baum. (ZF Friedrichshafen, Germany.) It was suggested that motor vehicle transmissions will change. This will not affect the scope for use of PM parts and may lead to increased use of sintered materials that satisfy
P.Sanchez et al. (PolytechnicUniversity of Madrid, Spain.) Cu-10%Sn powders, with and without additions of graphite or Ni coated graphite powder, were pressed and sintered in N-H. The alloys with Ni were heat treated to age harden. Pin-on-disc tests were carried out to evaluate wear and friction properties. Wear damage was assessed by scanning electron microscopy.
PM materials for synchronizer rings M.Krehl, R.Rau. (Sinterstahl GmbH, F~ssen, Germany.) The requirements of synchronizer rings in automotive transmissions were identified as generation of friction and torque for synchronizing, high wear resistance and high strength and toughness. Materials used have included forged brass, forged steel and PM steel. Materials for PM parts were discussed in terms of properties and costs.
Sinter hardening for production of transfer case sprocket M.Gagn~et al. (Quebec Metal Powders, Canada.) Sinter hardening of steel parts was reviewed with regard to methods and materials and the ability to make parts that may be difficult to quench due to size and/or shape. It was reported that sinter hardening had been used
www.metal-powder.net