MICROSTRUCTURE IN LASER FUSED HIGH SPEED STEEL W6Mo5Cr4V2(M2)

Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites grow into the melt and then the fine equiaxed cellularstructure appears in upper melt region nearly surface.The substructure of cellular grains anddendrites was observed to consist of martensite and retained austenile,while the carbides asM_6C_■ Cr_7C_3 and MC distributed at their boundaries.It is believed that the highermicrohardness up to HV_(0.1)=865-960 of the laser fused structure of the alloy is due to the oc-currence of martensite.

W6Mo5Cr4V2高速钢深冷处理研究

研究了深冷处理对W6Mo5Cr4V2高速钢显微组织、力学性能及耐磨性的影响。试验结果表明,深冷处理能减少W6Mo5Cr4V2高速钢中的残留奥氏体,析出超细碳化物,提高硬度和耐磨性;深冷处理对冲击吸收功影响不大。W6Mo5Cr4V2高速钢合适的深冷处理工艺为:温度-130^-150℃,保温时间以钢件冷透为准,处理次数一般为1次。

CW6Mo5Cr4V2与W6Mo5Cr4V2钢的性能比较

用试验比较了CW6Mo5Cr4V2（CM2）与W6Mo5Cr4V2（M2）钢的性能。试验表明，在相同淬火温度下，CM2的淬回火硬度和红硬性明显高于M2，淬火晶粒比M2粗大，冲击功比M2低。CM2在1160—1200℃淬火可获得优良的综合性能。在1220℃以上淬火，CM2的过热倾向显著，冲击功急剧下降。碳和钨钼含量的变化对CM2的淬火温度影响很大。要使CM2淬火过程易于控制，收窄其主要成分范围是关键。