核电设备用690镍基合金气体保护焊丝国产化研究

Development of 690 nickel-alloy welding wire for GTAW in nuclear power industry

针对核电设备用690镍基合金焊接材料依赖进口的现状,开展690镍基合金焊接材料的国产化研制。研制的690镍基合金气体保护焊焊丝WHS690M满足CAP1000及CAP1400核电站的要求,焊接工艺性良好,在不同焊接规范参数下,焊缝金属室温及高温力学性能波动较小,350℃抗拉强度≥485 MPa。对WHS690M及进口Inconel 52M焊丝熔敷金属进行高温失塑裂纹敏感性评估,并结合光学显微镜(OM)、扫描电子显微镜(SEM)及电子背散射衍射技术(EBSD),对晶粒取向和晶界特征进行观察。试验表明,焊缝金属DDC最小临界应变出现在1 050℃附近,进口Inconel 52M最小临界应变约为2.1%,WHS690M最小临界应变约为3.2%。

Aiming at the current situation that nuclear-grade 690 nickel-alloy welding wire depends on the imported products,its localization was studied. WHS690 M welding wire meets the requirement of AP1000 and CAP1400 nuclear power plant,which has good welding performance. At different welding parameters,mechanical properties of the weld metal at room temperature and high temperature are relatively stable,and the tensile strength reaches 485 MPa at 350 ℃. Strain-to-fracture( STF) test based on Gleeble-3500 thermo-mechanical simulator was performed to evaluate the DDC susceptibility of Inconel 52 M and WHS690 M. Combined with OM,SEM and EBSD,the characteristics of grain orientation and precipitation were analyzed. According to the test results,the critical cracking strain is 2. 1% for Inconel 52 M,while 3. 2% about for WHS690 M at 1 050 ℃.