F92/Super304H异种钢接头镍基填充焊缝裂纹分析  

Analysis of weld crack in F92/Super304H dissimilar steel joint with nickel-based welding material

作　　者：陈忠兵[1] 周龙 汤淳坡 孙志强[1] 尚建路 Chen Zhongbing;Zhou Long;Tang Chunpo;Sun Zhiqiang;Shang Jianlu(Suzhou Nuclear Power Institute,Suzhou 215004,Jiangsu,China;China Energy Taizhou Power Generation Co.,Ltd.,Taizhou 225327,Jiangsu,China)

机构地区：[1]苏州热工研究院有限公司,江苏苏州215004 [2]国家能源集团泰州发电有限公司,江苏泰州225327

出　　处：《焊接》2023年第5期13-17,28,共6页Welding & Joining

摘　　要：通过显微组织观测和裂纹形貌观察,分析ERNiCr-3焊丝填充的F92/Super304H异种钢接头焊缝裂纹性质与原因。结果表明,裂纹位于第4和5层焊道焊缝中心或近中心的树枝晶晶间或亚晶间,沿晶分布,裂纹面上可观察到方向性一致的树枝晶和自由凝固面形成的晶胞,裂纹具有典型的镍基焊缝金属凝固裂纹的形貌特征,为焊接凝固裂纹。该裂纹产生的原因是接头第4和5层焊道宽度达16~21 mm,每层单道焊道,焊道摆动宽度大,焊缝金属高温停留时间长,使以奥氏体结晶模式凝固的焊缝金属生成方向性极强的粗状发达的树枝晶,Ni,Nb,Si和Ti等元素偏析于树枝晶晶间或亚晶间,形成Ni-Nb,Ni-Si等低熔点共晶,在凝固收缩应变作用下,沿枝晶界或亚晶界开裂,镍基填充焊缝固有的凝固裂纹敏感性和接头焊接工艺因素是导致该裂纹产生的主要原因。Through the observation of microstructure and crack morphology,the crack properties and causes of F92/Super304H dissimilar steel welding joint filled with ERNiCr-3 wire were analyzed.The results show the crack was distributed along the crystal and located between dendrites or subcrystals in the center or near the center of the weld bead of the 4th and 5th layers.Dendrites with the same direction and crystal cells formed on the free solidification surface can be observed on the crack surface.The crack can be identified as welding solidification crack because of its typical morphological characteristics of weld metal solidification crack.The reasons for the crack were that the weld bead width of the 4th and 5th layers of the joint was 16~21mm,and each layer had a single weld bead with a large swing width.The wide weld bead caused the weld metal to stay at high temperature for a long time,and austenitic crystallization mode made the weld metal generate coarse dendrites with strong directivity.Elements such as Ni,Nb,Si and Ti have segregated between dendrites or subcrystals to form low melting point eutectic such as Ni-Nb and Ni-Si.Cracks were generated along dendrite grain boundaries or subcrystals because of the effect of solidification shrinkage strain.The inherent solidification crack sensitivity of nickel-based welding material and the factors of welding process were the main reasons for the crack.

关 键 词：镍基焊材 异种钢接头 凝固裂纹 树枝晶 低熔点共晶 

分 类 号：TG401[金属学及工艺—焊接]