Q370R球罐裂纹成因分析及预防措施

Cause Analysis and Preventive Measures of Cracks in Q370R Spherical Tank

对体积3000 m^(3)的Q370R球罐进行定期检验,发现外表面下极板环焊缝下熔合区处存在多处裂纹,采用磁粉检测、相控阵检测、硬度测定、金相分析、矫顽力法应力测定等检测方法,对裂纹成因进行了研究分析并提出预防措施。分析结果表明:低温环境下焊接工艺执行不到位,使焊接接头熔合区产生了淬硬组织,在残余应力作用下引起焊接接头的脆性断裂,导致了焊接冷裂纹的产生。通过此次检验,及时消除了该球罐在后续使用过程中因裂纹导致失效而造成严重安全事故的隐患,对企业安全生产具有重大意义。

The comprehensive inspection of 3000 m^(3)spherical tank made by Q370R showed that there were many cracks in the fusion zone near the lower plate girth weld on the outer surface.Magnetic particle testing,penetrant testing,hardness measurement,metallogenetic analysis,coercive force stress measurement and other detection methods were used to analyze the causes of cracks and some preventive measures were suggested.The analysis results showed that the welding process was not carried out in the low temperature environment,which caused the hardening structure in the fusion zone of the welded joint,and the brittle fracture of the welded joint was caused by the joint action of residual stress,which led to the generation of cold welding crack.Through this inspection,the hidden danger of serious safety accident caused by crack failure in the subsequent use of the spherical tank was eliminated in time,which is of great significance to the safe production of enterprises.