焊接电流对35CrMoA+S275NL异种钢焊接接头显微组织和硬度的影响

Influence of Welding Current on Microstructure and Microhardness of Dissimilar Steel Welded Joints of 35CrMoA+S275NL

采用自动TIG焊,选用不同的焊接电流,对35CrMoA+S275NL异种钢进行焊接。分析了焊缝和热影响区金属的显微组织;并测试了焊接接头的显微硬度。结果表明,焊接电流对热影响区的显微组织影响较小,但对焊缝金属中碳化物的大小及分布状态有较大影响;焊接电流为100A时,焊缝金属中的碳化物细小且分布均匀,其显微硬度分布也比较合理,更适合在低温条件下工作且存在交变载荷作用的零部件焊接。

The welded joints of dissimilar steel of 35CrMoA ＋ S275NL were prepared by TIG automatic welding process using different welding current.According to the specimens of welded joints,the analyses of the weld metal and the heat-affected zone metal are made,and the micro-hardness survey of whole welded joints was conducted.The results show that there is little influence on the microstructure of HAZ by different welding current,but carbide in size and distribution in welded metal have larger effects,when welding current is 100 A,the microstructure and property of the welded joint is more suitable to weld the products which can work at low temperature and bear alternated loads.