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Total quality management — The customer's requirements
Electrical and magnetic materials SYNTHESIS AND MAGNETIC PROPERTIES OF FERRITE-METAL COMPOSITE POWDERS N.Hiratsuka et al (Saitama University, Urawa, Japan) J.Japan Sm. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 9981001. (In Japanese). It is reported that composite powders of Ni-Zn ferrite and Ni-Fe alloy had been synthesised. Magnetic properties and structures are described.
Hard materials and tool steels CARBURIZATION OF RECYCLED TUNGSTEN-COBALT
15 to 1700.
20 nm the hardness
increased
to
MECHANICAL PROCESSING OF IRON POWDERS IN REACTIVE AND NONREACTIVE GAS ATMOSPHERES J.C. Rawers, R.C. Doan (US Bureau of Mines, Albany, USA) Metall. Mater. Zb-ans. A, Vol 25, No 2, 1994, 381-388. It is reported that a st,udy of mechanical alloying of Fe powders in inert and reactive gases had been carried out. It is reported that lwt%N would dissolve in Fe without the formation of nitrides and that, N remained in solution after HIP. N is reported to relard grain growth during carburization. MECHANICAL ALLOYING OF IRONSILICON POWDERS 0. Kohmoto
et al
(Okayama
University,
L.Shourong, Y.Huiqin (Tianjin Inst. of Hard Alloys, Tianjin, China) PM Technology, Vol 11, No 4, 1994, 260-265. (In Chinese). Precipitation of carbides in reduced, recycled W-Co composite powders, during carburization, was investigated. The phases WCos and W&o7 were converted into q type carbides at low temperatures and to flCo and coarse WC crystals at high tempertures. Fine WC crystals could be made from Wand C at 600 to 1100°C and from W2C and C at 750 to 1100°C. The Co was found to have no catalytic effect.
powder was investigated through changes in magnetic properties and Curie temperature, Tc. Initially there was no alloying, indicated by unchanged TZ. A second stage is charact.erized by large increases in calorllic value and coercive force which, with Tc, are reduced in the third stage of milling.
COMPOSITION CHANGES DURING BALL MILLING OF HARD ALLOY POWDERS
FORMATION OF FILMS ON SURFACE OF MECHANICAL ALLOYING MILLING BALL
L. Changxiu (Zigong Hard Alloy Factory, Sichuan, China) PM Technology, Vol 11, No 4, 1994, 294-297. (In Chinese). Contamination of hard alloy powders and carbides during ball milling was investigated, for a range of alloys and mill using atomic absorption materials, spectroscopy. In stainless steel mills the main contaminant was Fe, up t,o 0.4wt%. With hard alloy mills Co was picked up by the charge.
Mechanical alloying PREPARATION OF AMORPHOUS TITANIUM-SILICON POWDERS AND THEIR CONSOLIDATION Y. Syono et al (Tohoku University, Sendai, Japan.) J. Japan Sot. Powder a?Ld Powder Metallurgy, Vol 40, No 10, 1993, 943-946. (In *Japanese) An investigation of MA of Ti-Si powders and subsequent dynamic consolidation is described. The powders were refined to a grain size of 20 to 50 nm and then became amorphous. After shock consolidation at a pressure of 33 GF’a material with a Vickcr’s hardness of 1300 was obtained with partial recrystallization. After further recrystallization at 750°C to a grain size of
38
MPR
March 1995
Okayama, Japan) J.Japan Sot. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 939-942. (In Japanese). Mechanical alloying of Fe-6.5wt%Si
I. Ohnaka (Osaka University, Osaka, Japan) J.Japan Sot. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 955-958. (In Japanese) It is reported that the stainless steel balls used for milling Ti-Al-ZrOa-stearic acid mixtures in Ar bccamc coated with a layer of Ti-A-ZrOa 8 nm thick. The film was enhanced by the stearic acid and water of crystallization from the ZrOs gel used. INFLUENCEOFBORONCONTENTON MECHANICAL ALLOYING OF COPPERTITANIUM-BORON POWDERS 0. Matsumoto et al (Toshiba Tungaloy Co, Kawasaki, Japan) J.Japan Sot. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 959-962. (In Japanese). The effect of B additions on the MA of Cu-8wt!%;Ti powders was investigated. Elemental and prealloyed Cu-Ti powders were used. In the powders prepared from elements CL solid solution and a nonequilibiium Cu-Ti phase were formed which, after heat treatment, converted to CusTi with ultrafine precipitates of Ti boride. less of the non-equilibium phase was found in the powders made from prealloyed Cu-Ti.
Quality assurance and quality control TOTAL QUALITY MANAGEMENT CUSTOMER’S REQUIREMENTS
- THE
J. Pimblott. (Gates Rubber Co Itd, Dumfries, UK) Materials World, Vol 3, NO 1, 1995, 14-15. The concept of Total Quality Management is discussed. Standard specifications both for materials and products and for quality audit are considered. A simple model is used to integrate the factors involved. The importance of quality improvement and the role of the customer in setting standards are emphasized. The steps in establishing a Total Quality Management syst,em are outlined.
Refractory metals and alloys THERMAL SHOCK TESTS REFRACTORY METALS
FOR
P.A. Hahn et al (Austrian Research Centre, Seibersdorf, Austria) Int. J. Refiactoq Metals & Hard Matm-ials, Vol 12, No 5, 1993-1994, 269-282. Efforts to establish a standard test procecdurc for refractory metals are described. Flat PM specimens of W, MO and Ta were subjected to pulsed and continuous heating from a 10 kW laser. Spot and line traces of heat affected zones were made on the specimens. and microstructural and property changes were determined. W and MO showed grain growth at even small thermal loadings but litle change was found in Ta. In bend tests W showed thermal shock failure, MO was less affected and Ta retained mechanical strength. INFLUENCE OF PROCESSING ON HIGH STRAIN RATE BEHAVIOUR OF REFRACTORY METALS G. Kavichandran nology, Pasadena, als and Manu$ 1994, 1031-1046. The behaviour
(Calfornia Inst. of TechCalifornia, USA) MateriProcesses, Vol 9, No 6, of W, Ta and Hf, and their
alloys, at high strain rates is reviewed. W and Ta are reported to be strain rate sensitive. Ductility of W is sensitive to crystallographic orientation. Strain localization is found in W healy alloys at high strain rates. Ta and its alloys are shown to have good ductility depending on processing texture. Hf has good ductility and shows strain localization. The behaviour of refractory metal’s and alloys is discussed with respect to processing and structure.
Hard materials and tool steels CARBURIZATION OF RECYCLED TUNGSTEN-COBALT
15 to 1700.
20 nm the hardness
increased
to
MECHANICAL PROCESSING OF IRON POWDERS IN REACTIVE AND NONREACTIVE GAS ATMOSPHERES J.C. Rawers, R.C. Doan (US Bureau of Mines, Albany, USA) Metall. Mater. Zb-ans. A, Vol 25, No 2, 1994, 381-388. It is reported that a st,udy of mechanical alloying of Fe powders in inert and reactive gases had been carried out. It is reported that lwt%N would dissolve in Fe without the formation of nitrides and that, N remained in solution after HIP. N is reported to relard grain growth during carburization. MECHANICAL ALLOYING OF IRONSILICON POWDERS 0. Kohmoto
et al
(Okayama
University,
L.Shourong, Y.Huiqin (Tianjin Inst. of Hard Alloys, Tianjin, China) PM Technology, Vol 11, No 4, 1994, 260-265. (In Chinese). Precipitation of carbides in reduced, recycled W-Co composite powders, during carburization, was investigated. The phases WCos and W&o7 were converted into q type carbides at low temperatures and to flCo and coarse WC crystals at high tempertures. Fine WC crystals could be made from Wand C at 600 to 1100°C and from W2C and C at 750 to 1100°C. The Co was found to have no catalytic effect.
powder was investigated through changes in magnetic properties and Curie temperature, Tc. Initially there was no alloying, indicated by unchanged TZ. A second stage is charact.erized by large increases in calorllic value and coercive force which, with Tc, are reduced in the third stage of milling.
COMPOSITION CHANGES DURING BALL MILLING OF HARD ALLOY POWDERS
FORMATION OF FILMS ON SURFACE OF MECHANICAL ALLOYING MILLING BALL
L. Changxiu (Zigong Hard Alloy Factory, Sichuan, China) PM Technology, Vol 11, No 4, 1994, 294-297. (In Chinese). Contamination of hard alloy powders and carbides during ball milling was investigated, for a range of alloys and mill using atomic absorption materials, spectroscopy. In stainless steel mills the main contaminant was Fe, up t,o 0.4wt%. With hard alloy mills Co was picked up by the charge.
Mechanical alloying PREPARATION OF AMORPHOUS TITANIUM-SILICON POWDERS AND THEIR CONSOLIDATION Y. Syono et al (Tohoku University, Sendai, Japan.) J. Japan Sot. Powder a?Ld Powder Metallurgy, Vol 40, No 10, 1993, 943-946. (In *Japanese) An investigation of MA of Ti-Si powders and subsequent dynamic consolidation is described. The powders were refined to a grain size of 20 to 50 nm and then became amorphous. After shock consolidation at a pressure of 33 GF’a material with a Vickcr’s hardness of 1300 was obtained with partial recrystallization. After further recrystallization at 750°C to a grain size of
38
MPR
March 1995
Okayama, Japan) J.Japan Sot. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 939-942. (In Japanese). Mechanical alloying of Fe-6.5wt%Si
I. Ohnaka (Osaka University, Osaka, Japan) J.Japan Sot. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 955-958. (In Japanese) It is reported that the stainless steel balls used for milling Ti-Al-ZrOa-stearic acid mixtures in Ar bccamc coated with a layer of Ti-A-ZrOa 8 nm thick. The film was enhanced by the stearic acid and water of crystallization from the ZrOs gel used. INFLUENCEOFBORONCONTENTON MECHANICAL ALLOYING OF COPPERTITANIUM-BORON POWDERS 0. Matsumoto et al (Toshiba Tungaloy Co, Kawasaki, Japan) J.Japan Sot. Powder and Powder Metallurgy, Vol 40, No 10, 1993, 959-962. (In Japanese). The effect of B additions on the MA of Cu-8wt!%;Ti powders was investigated. Elemental and prealloyed Cu-Ti powders were used. In the powders prepared from elements CL solid solution and a nonequilibiium Cu-Ti phase were formed which, after heat treatment, converted to CusTi with ultrafine precipitates of Ti boride. less of the non-equilibium phase was found in the powders made from prealloyed Cu-Ti.
Quality assurance and quality control TOTAL QUALITY MANAGEMENT CUSTOMER’S REQUIREMENTS
- THE
J. Pimblott. (Gates Rubber Co Itd, Dumfries, UK) Materials World, Vol 3, NO 1, 1995, 14-15. The concept of Total Quality Management is discussed. Standard specifications both for materials and products and for quality audit are considered. A simple model is used to integrate the factors involved. The importance of quality improvement and the role of the customer in setting standards are emphasized. The steps in establishing a Total Quality Management syst,em are outlined.
Refractory metals and alloys THERMAL SHOCK TESTS REFRACTORY METALS
FOR
P.A. Hahn et al (Austrian Research Centre, Seibersdorf, Austria) Int. J. Refiactoq Metals & Hard Matm-ials, Vol 12, No 5, 1993-1994, 269-282. Efforts to establish a standard test procecdurc for refractory metals are described. Flat PM specimens of W, MO and Ta were subjected to pulsed and continuous heating from a 10 kW laser. Spot and line traces of heat affected zones were made on the specimens. and microstructural and property changes were determined. W and MO showed grain growth at even small thermal loadings but litle change was found in Ta. In bend tests W showed thermal shock failure, MO was less affected and Ta retained mechanical strength. INFLUENCE OF PROCESSING ON HIGH STRAIN RATE BEHAVIOUR OF REFRACTORY METALS G. Kavichandran nology, Pasadena, als and Manu$ 1994, 1031-1046. The behaviour
(Calfornia Inst. of TechCalifornia, USA) MateriProcesses, Vol 9, No 6, of W, Ta and Hf, and their
alloys, at high strain rates is reviewed. W and Ta are reported to be strain rate sensitive. Ductility of W is sensitive to crystallographic orientation. Strain localization is found in W healy alloys at high strain rates. Ta and its alloys are shown to have good ductility depending on processing texture. Hf has good ductility and shows strain localization. The behaviour of refractory metal’s and alloys is discussed with respect to processing and structure.