热锻模表面宽带激光熔覆超细碳化钨试验研究

Research of Superfine WC Coating on the Surface of Hot Die Made by Wide-Band Laser

本文在热作模具钢(H13)表面通过预置超细碳化钨合金层,通过高功率连续CO2宽带激光处理预置表面获得熔覆层。采用光学显微镜和扫描电子显微镜(SEM)观察了熔覆层组织形貌,用X射线衍射仪(XRD)进行熔覆层物相分析,用X射线应力仪进行残余应力分析。测试了处理前后熔覆层显微硬度、耐磨性以及残余应力的变化。结果表明:激光处理后,表面平整光滑,组织细密,熔覆层组织由等轴晶、柱状树枝晶、细小的胞状晶和平面晶的结合带组成,厚度约为0.4mm,表面残余压应力得到显著提高,硬度为基体的1.8倍,耐磨性得到较大的提高。

Superfine WC alloy coating was prepared on the surface of hot die steel（H13） and then treated by high power continuous wave（CW）CO2 wide-band laser. Scanning electron microscopy （SEM） was used to observe the morphologies of coating. X-ray diffraction （XRD） was employed to analyze the microstructure of coating. X-ray stress meter was utilized to test residual stress. The changes of micro-hardness, wear resistance and residual stress were tested. The results revealed that the strengthened coating had good performance such as smooth surface, uniform component, fine microstructure. The microstructure of coating consisted of isometric crystals, columnar crystals and a dilution zone of fine cystiform crystals with flat crystals. The thickness of whole coating was about 0. 4mm. The micro-hardness of strengthened coating was 1.8 times of parent metal. The wear resistance and the residual compressive stress were improved greatly.