Structure and mechanical properties of injection molded high speed steels have been investigated by using water atomized powder. Debinding was performed by solvent extraction at 358K with n-heptane, followed by final thermal debinding at various temperature. The debound specimens were sintered at 1473K-1573K for 3.6ks in various gas mixtures of H₂ and N₂. The results obtained are summarized as follows:
(1)Solvent extraction was effective debinding process for a considerable shortening the binder removal time and preventing the distortion.
(2)Sintered density was increased with an increase of sintering temperature, at 1523K in N₂ fully densified materials were obtained and were also seen finely and uniformly dispersed carbides precipitated on the matrix.
(3)Although the size of carbides precipitated was decreased with increasing the fraction of H₂ in the sintering atmosphere, the density and hardness declined. This is due to a shortage of liquid phase content because of the decarburization.