摘要
针对厚度70 mm左右的Q345R中厚钢板对接焊缝超声波检测出现缺陷的问题,采用金相检验、扫描电镜、能谱分析等方法对出现焊接缺陷以及未出现缺陷的钢板进行对比研究,分析了Q345R中厚板在埋弧焊过程中,厚度中心处热影响区出现缺陷的主要原因。结果表明,缺陷类型属于热裂纹中的液化裂纹。缺陷产生的原因一方面是轧制过程中硫化物等夹杂物在钢板边缘聚集,导致了局部杂质元素含量超标,另一方面由于钢板厚度中心处偏析导致的碳、锰元素含量升高,导致中心区域力学性能下降,在焊接循环热应力的作用下裂纹从应力集中处产生,并沿热影响区扩展。通过控制母材偏析程度、减小返修焊接热输入等方法,可减少缺陷的产生。
In view of the phenomenon that defects are detected in Q345R medium and heavy steel plate butt welds by ultrasonic inspection,comparative study on Q345R plates with and without welding defects was carried out by metallographic examination,SEM and EDS,in order to analysis the contributing factor to welding defects in heat affected zone which appeared in thickness center of Q345R heavy steel plates while submerge-arc welding.The result shows that the type of defects is liquation cracking of hot cracking.Both the excessive impurity elements in the center area caused by aggregation of sulfide inclusion on the steel plate edges,and the decrease of mechanical properties in thickness center which due to carbon and manganese element centerline segregation of slab,resulted in the initiation and growth of cracks.By controlling the quality of base metal,decreasing the heat inputs of welding,the amount of welding defects in Q345R medium and heavy steel plate butt welds can be reduced.
作者
郭志成
刁旺战
徐祥久
Guo Zhicheng;Diao Wangzhan;Xu Xiangjiu(Harbin Boiler Company Limited,Harbin 150046,Heilongjiang,China;State Key Laboratory of Efficient and Clean Coal-Fired Utility Boiler,Harbin 150046,Heilongjiang,China)
出处
《机械制造文摘（焊接分册）》
2020年第4期16-20,共5页
Welding Digest of Machinery Manufacturing
关键词
焊接缺陷
液化裂纹
中心偏析
welding defects
liquation cracking
centerline segregation
