稀土镁对W6Mo5Cr4V2高速钢中共晶碳化物粒化的影响

冶炼和铸造了不同稀土镁含量的W6Mo5Cr4V2高速钢,并对铸态钢材进行退火及锻打,检测了不同状态下的显微组织,并用Gleeble模拟了钢材的高温性能。结果表明:稀土镁能使铸态W6Mo5Cr4V2钢中网状碳化物组织断裂;随着钢中稀土镁含量的增加和锻打压下量的增大,碳化物粒化度提升;热模拟表明W6Mo5Cr4V2钢的第I高温脆性区为熔点到1180℃,第Ⅱ高温脆性区为950~800℃;综合高温塑性区极窄,为1170~1190℃。

Effects of Rare Earth Magnesium on Eutectic Carbide Granulation in High Speed Steel W6Mo5Cr4V2

High speed steels W6Mo5Cr4V2 with different contents of rare earth magnesium were smelt and moulded and then the steels were annealed and forged. Microstructures of the samples were observed and the properties at high temperature were investigated by the thermal simulator Gleeble. The results show that reticulation carbide structures are ruptured by the addition of rare earth magnesium to the moulded steel W6Mo5Cr4V2. With the increasing of rare earth magnesium contents and forging reductions, the degree of granulation for carbide is improved. Thermal simulation results indicate that the first high temperature brittleness area lies in the range from melting point down to 1180 oC, and the second high temperature brittleness area is between 950 oC and 800 oC; however, the comprehensive high temperature ductility area is very narrow, which is from 1170 oC to 1190 oC.