激光表面重熔对高速钢显微组织的影响

EFFECT OF LASER SURFACE REMELTED PROCESSING ON MICROSTPUCTURE OF HIGH SPEED TOOL STEEL

采用CO_2连续波激光对W18Cr4V高速钢进行表面重熔处理。分析结果表明,经激光重熔后高速钢的显微组织明显细化,重熔层内的相构成为马氏体、奥氏体,过剩的δ铁素体和M_6C、M_(23)C_6型碳化物。枝晶内为孪晶马氏体和部分板条马氏体。枝晶间为富合金元素的奥氏体和M_6C碳化物,孪晶马氏体上沿孪晶面有M_(23)C_6碳化物共格析出。激光扫描速度增加、δ铁素体量增多,重熔层显微硬度下降。

The User remelted processing on W18Cr4V high speed tool steel has been done using a CO_2 continuous wave leaer device. It was revealed that microetructure of high speed tool steel was fined remarkably by laser remelted processing. The phases in remelted layer were martensite,austenite,over 8 -ferrite and M_6C,M_(23)C_6 carbides. The prodominant twin martensite and partial lath martensite existed in dendrite. There were both austenite rich in alloy elements and M C carbide in interdendritic regions. The thin plate-like M_(23)C_6 Carbide precipitated coherently on the twin plane.The higher laser scanning speed,the more amount of -ferrite in remelted layer and the lower microhardness.