激光扫描速度对40Ct钢激光表面合金化层组织性能的影响

为了改善金属拉拔卷筒40Cr铜的性能,采用Mo制成合金粉末,用CO2激光对卷筒表面进行激光合金化处理。研究激光合金化的工艺参数,对不同扫描速度下合金化层的质量进行比较并对其组织进行分析。结果表明：激光合金化工艺参数为：功率P=2．0kW,焦距f=315mm,搭接率为40％,扫描速度V=6mm／s,获得的合金化层具有良好的组织和性能,没有裂纹产生,未发现不熔物,组织较均匀。     

Influence of yttrium on laser surface alloying organization of 40Cr steel

In order to improve the performance of the metal rollers,Mo+Y2O3 alloy powders were used to coat uniformly on the surface of40Cr steel roller substrates for the laser surface alloying treatment by a CO2 laser,The results showed that many good consequences were obtained after adding the rare earth oxide Y2O3.The crystal grains of the alloy layer were significantly refined.The boundary of crystal grainswas strengthened.The uniformity and density of the microstructure were increased.The hardness and wearing resistance of the alloy layerwere considerably improved.The valence electron structure analysis of the alloy layer was made by the empirical electron theory of solidsand molecules(EET).The calculated results demonstrated that Y should be mixed in the first stage and Fe should be in the eighteenth hybridbands.The analyzed outcomes illustrated that the electron theory of the solid solution shows the strengthening effect on the alloying layer,which has enhanced bond and confirmed the experimental results.     

Y_2O_3含量对40Cr钢激光表面合金化组织与性能的影响

为了改善金属拉拔卷筒的耐磨性能,采用CO2激光对40Cr钢拉拔卷筒表面进行激光合金化处理,利用OM、XRD、显微硬度计、SEM、磨损试验机研究了Y2O3对合金化层的组织性能的影响。结果表明：Y2O3添加量在0～2.5%变化时,随着Y2O3含量的增加,合金化层组织逐渐变细,Y2O3含量在1.0%时,合金化层组织最细,Y2O3的含量大于1.0%时,合金化层的组织反而变的粗大。未添加Y2O3时,合金化层除了基体相α-Fe外,同时还包括MoC、Cr3Mo、Cr7C3和Fe2MoC等相。添加Y2O3后,还生成了少量的FeCrMo相。Y2O3还可以抑制Mo、Cr等原子由晶内向晶界扩散。Y2O3添加量为1.0%时,合金化层具有最高的硬度和耐磨性,当Y2O3含量大于1.0%时,合金化层的硬度和耐磨性随着Y2O3含量的增加反而降低。     

Y2O3对40Cr钢激光表面合金化组织和性能的影响

为了改善金属卷筒的组织性能,采用Mo+Y2O3制成合金粉末,将粘接剂均匀涂覆在40Cr钢基材表面,用CO2激光器对材料表面进行了激光合金化处理。利用扫描电子显微镜、X射线衍射仪、显微硬度计、磨损试验机研究了Mo+Y2O3对合金化层的硬度、耐磨性、组织结构、形成机理的影响。结果表明,在加入稀土氧化物Y2O3后,合金层晶粒显著细化,晶界得到强化,增加了显微组织的均匀性、致密性,硬度、耐磨性得到显著提高,有利于提高金属卷筒表面的硬度和耐磨性。