Powder metallurgy steel

H.A. Ferguson, Heat Treating of Powder Metallurgy Steels, Heat Treating, Vol 4, ASM Handbook, ASM International, 1991, p 229-236... 

Rare-earth-modified powder metallurgy steel... 

Fig. 5. Micrographs of the microstructure of fully hardened and tempered tool steels produced by the powder metallurgy technique, showing uniform distribution and fine carbide particles in the matrix, (a) M-42 (see Table 6) and (b) cobalt-free AlSl T-15 having a higher concentration of fine carbide...

It maybe economical, therefore, to use these materials at or near the cutting edge instead of as the whole insert. The development of tools of TiC (40—55%) or TiN (30—60%) in a steel matrix on a steel core using powder metallurgy technology suggests a similar approach for cemented carbides as the need arises. 

In a chemical vapor deposition (CVD) variant of conventional powder metallurgy processing, fine chromium powder is obtained by hydrogen reduction of Crl2 and simultaneously combined with fine thorium(IV) oxide [1314-20-17, H1O2, particles. This product is isostaticaHy hot pressed to 70 MPa (700 atm) and 1100°C for 2 h. Compacts are steel clad and hot roUed to sheets (24). 

Advances in powder metallurgy have brought the technology to a point where it could be applied advantageously to the production cf highly stressed, critical components. Specifically, PM forging now can replace the conventional forging of certain low-alloy steel components. 

German, R.M. Powder Metallurgy) of Iron and Steel, John Wiley Sons, Inc.. New York, NY, 1998,... 

Zh.I. Dneladze, R.P. Shchegoleva, L.S. Golubeva and others (1978) Powder Metallurgy of Steels and Alloys, Metallurgy, Moscow. 

In powder metallurgy very high cooling rates are encountered. Calculations lead to an estimate of lO -ICH °C/s for the solidification of argon atomized steel particles [9], Welding and powder metallurgy are thus not directly covered by the experiments reported in the present work. 

About 8% of HSS are produced today by powder metallurgy (P/M). This amount is steadily increasing, in particular in the field of cutting tools (gear cutter, endmills, taps, and broaches) [8.10]. More carbides can be added compared to conventional HSS and a finer particle size and more uniform distribution of the carbides can be achieved. However, the costs are still higher than for conventional tool steels, which retards a more general applicability [8.10]. 

A number of processes were developed that use CVD, PVD, plasma spray, powder metallurgy, SHS, and galvanoforming. Several combined processes were also developed including CVD/CVI, PM/CVD, SHS/HIP, and plasma spray/galvanoforming. Various FGM samples were fabricated such as disks of SiC/C, AlN/SiC, PSZ/stainless steel, PSZ/Ni, TiC/Ni, Cr3C2/Ni, TiB2/Cu nose cones of SiC/CC and rods of PSZ/Ni. 

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