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Effects of drilling parameters on machinability of PM materials
TUNGSTEN CARBIDE-COBALT FILMS PREPARED BY ARC ION PLATING Z.Jin et al. (Academica Sinica, Shenyang, China.) Int. J Refractory Metals Hard Muter., Vol 16, No 2, 1998, 95-98. It is reported that WC-(0, 4 and 15)%Co films had been deposited by arc ion plating onto stainless steel substrates. Rates of deposition and microhardness of the deposits were measured and structures investigated by scanning electron microscopy. As deposition rate increased the structure of the deposit, columnar grains, was refined. EFFECT OF SHORT TIME THERMOMECH.4NICAL CIRCULATION IN BINDER IN TUNGSTEN CARBIDECOBALT W.Liu et al. (Akita University, Akita, Japan.) Int. J. Refractory Metals Hard Mater., Vol 16, No 2, 1998, 99-106. Structural evolution in WC-2O%Co, during thermal cycling or cyclic compressive stressing, was investigated. The volume fraction of bCo decreased and that of &Co increased. Effects of heat treatment, as-sintered, as-quenched or quenched and tempered, were studied. The proportion of PCo was highest in the quenched samples and lowest in the assintered specimens. NANOPHASE AND SUPERFINE INJECTION MOULDED CEMENTED CARBIDES M.J.Yang, R.M.German. (Pennsylvania State University, Pennsylvania, USA.) Znt. J. Refractory Metals Hard Mater., Vol 16, No 2, 1998, 107-117. A study of injection moulding of two superfine and one nanophase WC-Co powders, with small amounts of other additives, is described. The nanophase material had high strength and hardness but poor mouldability. As-received the nanophase powders were hollow agglomerates which were milled to make them suitable for injection moulding. The study concentrated on effects of binder related and process factors on the moulding process.
Mechanical
alloying
PRODUCTION SCALE MECHANICAL ALLOYING USING CYCLIC OPERATION H.Okouchi et al. (Fukuda Metal Foil and Powder Co Ltd, Kyoto, Japan.) Metall, Vol 51, No 10, 1997, 568-572. (In English.) Production of powders with flakelike morphology is discussed and it is noted that long milling times may be needed. Studies, using a horizontal
rotary ball mill, to process Ag powder, with the intention of reducing milling times, are described. The design of mill allows laboratory scale, 11, or production scale, 1001, mills to be constructed. The present study concentrated on production of mechanically deformed powders by cyclic operation of milling and control of critical milling parameters.
of factors are involved. Standard machinability tests do not work for PM materials. Several approaches to evaluation of machinability of a PM steel were described and discussed with consideration of weaknesses in each technique. A laboratory simulation approach was described and correlated with real machining.
Metal injection
Novel techniques
moulding
INTERNAL DEFECT EVALUATION FOR INJECTION MOULDED SPECIMENS N.Hirose et al. (Tokyo Industrial Technology Research Inst., Tokyo, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 9! 1997, 851-857. (In Japanese.) Internal defects in MIM samples were investigated as functions of injection speed and location and distribution of defects in the samples. A connection was found between defects and crystallization and shrinkage in the binder. The study used 316L stainless steel with a polypropylene binder. PM2TEC’98. The Abstracts which follow are from papers which were presented at the 1998 International Conference on Powder Metallurgy and Particulate Materials, held in Las
Machinability EFFECTS OF DRILLING PARAMETERS ON MACHINABILITY OF PM MATERIALS M.L.Gagne, J.A.Danaher. (Quebec Metal Powders Ltd, Canada.) Machining of PM materials was discussed with consideration of the use of machinability enhancers. An investigation of the efficiency of MnS and BN, added to sintered F-0005 and F-0205 steels, under a range of drilling conditions was described. Relationships between thrust force, torque, tool wear life and too1 were discussed. Machinability of these steels, with and without machinability enhancers, and steels used for automotive components, were compared. ALTERNATIVE APPROACH TO MACHINABILITY TESTS FOR PM MATERIALS T.M.Cadle et al. (Zenith Sintered Products Inc, USA.) Methods for assessment of machinability, the parameters used, ability of a material to form a chip and the tendency of a workpiece to damage or destroy a tool were reviewed. A very large number
PRODUCTION OF STEEL FOAM BY PM H.H.Eifert et al. (Fraunhofer Resource Centre-Delaware, USA.) Production of metallic and alloy foams with very low densities, for a variety of applications, was reviewed. Selection of steel powders for foaming and foaming agents was outlined. Properties of agents to make steel foams were evaluated. Potential applications were identified. TRANSFORMATION AND APPLICATIONS OF METAL FIBRES INTO USEFUL PRODUCTS R.de Bruyne. (N.V.Bekeart, SA, Belgium.) Application of metallurgical, polymer and textile technologies to make articles from metal fibres was discussed. Applications considered included filter media, medical products, magnetic shields and anti-static metallic ‘textiles’. Techniques such as sintering, welding, brazing and impregnation could be used. A wide range of products was shown to be possible. SURFACE METALLIZATION OF DIAMOND BY SELF-PROPAGATING HIGH TEMPERATURE SYNTHESIS W.Yikun, Y.Qing. (Yozhou University, China.) Metallization of diamond, as a means of improving the bond between matrix materials and diamond, was discussed. It was reported that self-propagating high temperature synthesis had been used to place a metallic carbide on diamond surfaces. Al and Ti powders were added to metal powders. During hot pressing carbides were formed at the diamond/matrix interface. The bond between coated diamond and matrix was shown to be greater than that between uncoated diamond and the matrix.
Graded materials CHALLENGES AND OPPORTUNITIES FOR PM IN FUNCTIONALLY GRADED MATERIALS A.Zavaliangos. USA.)
(Drexel
University,
MPR February 1999 37
Mechanical
alloying
PRODUCTION SCALE MECHANICAL ALLOYING USING CYCLIC OPERATION H.Okouchi et al. (Fukuda Metal Foil and Powder Co Ltd, Kyoto, Japan.) Metall, Vol 51, No 10, 1997, 568-572. (In English.) Production of powders with flakelike morphology is discussed and it is noted that long milling times may be needed. Studies, using a horizontal
rotary ball mill, to process Ag powder, with the intention of reducing milling times, are described. The design of mill allows laboratory scale, 11, or production scale, 1001, mills to be constructed. The present study concentrated on production of mechanically deformed powders by cyclic operation of milling and control of critical milling parameters.
of factors are involved. Standard machinability tests do not work for PM materials. Several approaches to evaluation of machinability of a PM steel were described and discussed with consideration of weaknesses in each technique. A laboratory simulation approach was described and correlated with real machining.
Metal injection
Novel techniques
moulding
INTERNAL DEFECT EVALUATION FOR INJECTION MOULDED SPECIMENS N.Hirose et al. (Tokyo Industrial Technology Research Inst., Tokyo, Japan.) J. Jpn Sot. Powder Powder Metall., Vol 44, No 9! 1997, 851-857. (In Japanese.) Internal defects in MIM samples were investigated as functions of injection speed and location and distribution of defects in the samples. A connection was found between defects and crystallization and shrinkage in the binder. The study used 316L stainless steel with a polypropylene binder. PM2TEC’98. The Abstracts which follow are from papers which were presented at the 1998 International Conference on Powder Metallurgy and Particulate Materials, held in Las
Machinability EFFECTS OF DRILLING PARAMETERS ON MACHINABILITY OF PM MATERIALS M.L.Gagne, J.A.Danaher. (Quebec Metal Powders Ltd, Canada.) Machining of PM materials was discussed with consideration of the use of machinability enhancers. An investigation of the efficiency of MnS and BN, added to sintered F-0005 and F-0205 steels, under a range of drilling conditions was described. Relationships between thrust force, torque, tool wear life and too1 were discussed. Machinability of these steels, with and without machinability enhancers, and steels used for automotive components, were compared. ALTERNATIVE APPROACH TO MACHINABILITY TESTS FOR PM MATERIALS T.M.Cadle et al. (Zenith Sintered Products Inc, USA.) Methods for assessment of machinability, the parameters used, ability of a material to form a chip and the tendency of a workpiece to damage or destroy a tool were reviewed. A very large number
PRODUCTION OF STEEL FOAM BY PM H.H.Eifert et al. (Fraunhofer Resource Centre-Delaware, USA.) Production of metallic and alloy foams with very low densities, for a variety of applications, was reviewed. Selection of steel powders for foaming and foaming agents was outlined. Properties of agents to make steel foams were evaluated. Potential applications were identified. TRANSFORMATION AND APPLICATIONS OF METAL FIBRES INTO USEFUL PRODUCTS R.de Bruyne. (N.V.Bekeart, SA, Belgium.) Application of metallurgical, polymer and textile technologies to make articles from metal fibres was discussed. Applications considered included filter media, medical products, magnetic shields and anti-static metallic ‘textiles’. Techniques such as sintering, welding, brazing and impregnation could be used. A wide range of products was shown to be possible. SURFACE METALLIZATION OF DIAMOND BY SELF-PROPAGATING HIGH TEMPERATURE SYNTHESIS W.Yikun, Y.Qing. (Yozhou University, China.) Metallization of diamond, as a means of improving the bond between matrix materials and diamond, was discussed. It was reported that self-propagating high temperature synthesis had been used to place a metallic carbide on diamond surfaces. Al and Ti powders were added to metal powders. During hot pressing carbides were formed at the diamond/matrix interface. The bond between coated diamond and matrix was shown to be greater than that between uncoated diamond and the matrix.
Graded materials CHALLENGES AND OPPORTUNITIES FOR PM IN FUNCTIONALLY GRADED MATERIALS A.Zavaliangos. USA.)
(Drexel
University,
MPR February 1999 37