高氮钢双面双弧TIG焊接接头组织性能研究

摘要

采用双机器人协同双面双弧TIG焊接方法,通过使用不同比例混合的Ar-N2保护气对高氮奥氏体不锈钢进行TIG焊接,分析了焊接接头显微组织、硬度和力学性能,研究了N2的加入对焊接接头组织性能的影响.结果表明,焊缝凝固模式始终为A模式,但是N2的加入会改变焊缝区微观组织形貌;硬度测试显示,焊缝区硬度值均低于母材硬度值并高于热影响区硬度值;接头抗拉强度先增大后减小,拉伸断口为韧性断裂,且均断裂于焊缝位置.%The paper aims to research on the weldability of 7 mm thick high nitrogen austenitic stainless steel by DSAW.By adjusting the composition of Ar+N2protection gas, the microstructure, hardness, mechanical properties of the welded joints are studied. The results show that the nitrogen content in the weld has significant effect on the weld solidification mode and microstructure.The solidifi-cation mode is A and the microstructure is single austenite;the micro-hardness of the weld metal zone changes with the N2-content change,and the hardness value of weld metal zone is lower than are of the base metal,but higher than one of HAZ,it is the first to increase the fensile strength of the joint,the last to reduce it. The tensile fractures are ductile fracture at the welding position.