Spray Forming 으로 제조된 고속도공구강에서 열간 단조에 따른 탄화물 분포 및 인성의 변화 = Variations of Carbide Distribution and Toughness after Hot-Forging in a Spray Formed High Speed Steel

다국어 초록 (Multilingual Abstract)

ASP30 high speed steel billets showing different carbide microstructures of M₂C carbide cell and M_6C carbide cell have been prepared by the spray forming process. The variations of carbide distribution and bend fracture properties after hot forging have been investigated. Direct hot forging of spray formed materials has resulted in the formation of carbide clusters along hot working direction and bend fracture properties have been deteriorated. On the other hand, the metastable M₂C carbide has been completely decomposed to MC and M_6C carbides after high temperature exposure. The carbides are more uniformly distributed after forging and the bend properties increase significantly with decomposition treatment. The formation of M₂C carbide during solidification is preferable for obtaining a fine homogeneous carbide distribution after decomposition treatment and hot forging. The bend fracture properties of the spray formed ASP30 alloy have been found to be comparable to those of ASP30 alloy fabricated by powder metallurgy.