Solidification microstructure and M{sub 2}C carbide decomposition in a spray-formed high-speed steel
- Research Inst. of Industrial Science and Technology, Pohang (Korea, Republic of). Advanced Materials Div.
The solidified carbide morphology, the decomposition behavior of the M{sub 2}C carbide, and the carbide distribution after forging of an Fe-1.28C-6.4W-5.0Mo-3.1V-4.1Cr-7.9Co (wt pct) high-speed steel prepared by spray forming have been investigated. The spray-formed microstructure has been characterized as a discontinuous network of plate-shaped M{sub 2}C carbides and a uniform distribution of fine, spherical MC carbides. The metastable M{sub 2}C carbides formed during solidification have been fully decomposed into MC and M{sub 6}C carbides after sufficient annealing at high temperatures. Initially, the M{sub 6}C carbides nucleate at M{sub 2}C/austenite interfaces and proceed to grow. In the second stage, the MC carbides form either inside the M{sub 6}C carbides or at the interfaces between M{sub 6}C carbides. With this increasing degree of decomposition of the M{sub 2}C carbide, the carbides become more uniformly distributed through hot forging, which produces a significant increase in ultimate bend strength. The decomposition treatment of M{sub 2}C carbide has been found to be most important for obtaining a fine homogeneous carbide distribution after hot forging.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 616264
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Vol. 29, Issue 5; Other Information: PBD: May 1998
- Country of Publication:
- United States
- Language:
- English
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