焊接工艺对Incoloy800H合金焊缝晶间腐蚀性能的影响  

Effect of welding process on intergranular corrosion of Incoloy 800H alloy welds

作　　者：杨二娟[1] 刘福广[1] 李勇[1] 米紫昊[1] 雒晓涛[2] YANG Erjuan;LIU Fuguang;LI Yong;MI Zihao;LUO Xiaotao(Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,China;Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安热工研究院有限公司,西安710054 [2]西安交通大学,西安710049

出　　处：《焊接》2025年第2期76-83,90,共9页Welding & Joining

基　　金：中国华能集团科技项目(HNKJ20-H47,TN-20-TYK09)。

摘　　要：【目的】旨在验证不同焊接工艺在高温气冷堆蒸汽发生器高温端传热管Incoloy800H合金焊接堵管的适应性。【方法】分别采用激光焊和钨极惰性气体保护焊(Tungsten inert gas welding,TIG)制备了自熔焊Incoloy800H合金焊接接头,通过“硫酸铁(Ⅲ)-硫酸试验”方法测试了不同焊接接头以及母材的抗晶间腐蚀性能,并借助光学金相显微镜、扫描电子显微镜和X射线能谱仪对焊接接头显微组织、腐蚀形貌与产物以及腐蚀机理进行了研究。【结果】结果表明,更高的功率密度使得激光焊接接头的焊缝与热影响区宽度显著低于TIG焊接接头,焊接热影响区内存在沿奥氏体晶界呈带状分布的亚微米碳化铬与离散分布的微米尺度碳化钛析出颗粒。晶间腐蚀测试结果表明,激光焊接接头的腐蚀速率与母材相当,约为TIG焊接接头的39.0%。同一焊接接头内部热影响区的腐蚀深度最大,其次为焊缝与母材。【结论】碳化铬析出导致的晶界贫铬是晶间腐蚀性能存在差异的主要原因。[Objective]The aim is to examine the validity of different welding processes on welding plugging of the Incoloy 800H heat exchange tubes of the stream generator in high temperature gas cooled-reactor.[Methods]Self-fusion weldments of Incoloy 800H alloy are made by TIG and laser welding.The resistance to intergranular corrosion performance of both different welded jionts and base meterial is measured with FeSO4(III)-H2SO4 solution.Optical microscopy,scanning electron microscopy and energy dispersive spectrometer are used to study microstructure of welded joints,the morphology and products of corrosion,as well as the corrosion mechanism.[Results]Results show that the higher power density results in a significantly narrower weld and heat affected zone width for the laser welded joints compared to the TIG welded joints.Submicrosized Cr23C6 and microsized TiC precipitates are observed along the grain boundaries within the heat affected zones.The intergranular corrosion test shows that the corrosion rate of the laser welded joints is comparable to that of the base material,and it is approximately 39.0%of the TIG joints.The corrosion depth of the heat affected zone inside the same welded joint is the largest,followed by the weld and the base material.[Conclusion]The Cr depletion at grain boundaries caused by chromium carbide precipitation is the main reason for the difference in intergranular corrosion resistance.

关 键 词：Incoloy800H合金 晶间腐蚀 激光焊 钨极惰性气体保护焊 

分 类 号：TG442[金属学及工艺—焊接]