Abstract
In order to test the feasibility of using the MIM approach to attain the high performance high speed steels, many processing variances of molding, debinding, sintering and heat treatment conditions were investigated in this paper by using a gas atomized high speed steel powder. The results obtained are summarized and compared with a water atomized powder as follows;
For the debinding of gas atomized powder compounds, about 39% of the total binder weight was removed by solvent extraction for 14.4ks, which was larger than that of water atomized powder compounds(about 33%). This was mainly due to the powder characteristics, for example the shape and size of gas atomized powder were rounder and coarser than that of water atomized powder. Since the carbon content of gas atomized powder compacts was unchanged after sintering in pure N2, densification of the compact started at lower sintering temperature compared with water atomized powder compacts. Sintered microstructures of gas atomized powder compacts showed a little coarse and angular carbides precipitated in the matrix.
