奥氏体不锈钢堆焊层焊接缺陷分析及改进措施

Analysis of Welding Defects of Austenitic Stainless Steel Surfacing Layers and Improvement Measures

以共享公司生产的某核电高中压外缸为例,在焊接奥氏体耐腐蚀堆焊层时,堆焊层区域经无损检测、焊接完成后经渗透检测发现有显示。随即取样后进行显微组织观察,发现有微裂纹及夹渣缺陷。微裂纹缺陷是因为高温状态下生成的NbC相使晶界发生偏移,夹渣缺陷是因为奥氏体焊材本身材料特性导致。通过“不预热、小电流、低热输入、层温控制≤150℃及窄摆动”的方式,并经过现场验证焊接工艺,成功解决该问题,并对后续同类产品提供了宝贵经验。

Taking the outer cylinder of a nuclear power plant produced by Kocel as an example,when welding an austenitic corrosion-resistant surfacing layer,the surfacing layer area was subjected to nondestructive testing,and the penetration test found that there were signs after welding was completed.Microcracks and slag defects are found after sampling and observation through a microscope.The microcrack defect is due to the deviation of the grain boundary caused by the NbC phase formed at high temperature,and the slag inclusion defect is caused by the material characteristics of austenitic welding consumables.Through“no preheating,small current,low heat input,layer temperature control≤150°C,and narrow swing”mode combined with on-site verification welding process,the problems have been successfully solved,providing valuable experience for follow-up similar products.