模具钢表面激光熔覆硬面合金层改性的研究

Study of Laser Cladding on Die Steel Surface

应用１．５ｋＷ横流式ＣＯ２激光器将ＮｉＷＣ２５，Ｎｉ５５，Ｆｅ４５０，ｓｔｅｌｉｔｅ１２等４种硬面合金粉末涂覆在Ｙ４模具钢的表面，然后用扫描电镜能谱仪、光学显微镜、Ｘ射线衍射仪、显微硬度计、耐磨实验机等分别对合金层的剖面元素分布、合金层的微观组织、相组成、显微硬度及耐磨性等进行了较详细的测定分析。研究结果表明，合金涂覆层与基材在激光作用下能形成良好的冶金结合；合金层的组织是以过饱和奥氏体基相上弥散分布着碳化物和硼化物的多元共晶组织，该合金层具有优于Ｙ４模具钢的耐磨性能，其中以ＮｉＷＣ２５合金层的耐磨性最好。

Four kinds of hard facing alloy powders (NiWC25,Ni55,Fe450,stellite12) were cladded onto the surface of the die steel(Y4) by crossstyle carbon dioxide laser with 1 5kW capacity. The microstructure as well as several mechanical properties of the cladded layers were studied by EDX SEM,X ray diffraction and wearing machine. It is shown that ①a good banding between the alloy layer and matrix (Y4) can be obtained by the laser cladding,②the microstructure of the alloy layers consists of a multiplex eutectic mixture containing complex carbides and boride on the over saturation austenetic matrix,③the wearing resistance of the four kinds of the alloy layer is evidently better than that of the die steel base,④NiWC25 cladding layer appeared to be the best in the wearing resistance.