Q235B-Z焊管焊缝处压扁开裂原因分析与控制措施  

Cause Analysis and Control Measures of Flattening Cracking at Welds of Q235B-Z Welded Pipe

作　　者：果超 张丹 赵琼 Guo Chao;Zhang Dan;Zhao Qiong(Technical Center of Shanxi Jianlong Industrial Co.,Ltd.,Yuncheng Shanxi 043800,China)

机构地区：[1]山西建龙实业有限公司技术中心,山西运城043800

出　　处：《山西冶金》2023年第7期32-34,共3页Shanxi Metallurgy

摘　　要：某钢厂生产的Q235B-Z热卷在HFW焊管加工过程中出现批量压扁开裂质量问题。经分析发现:钢中氧化铝夹杂在凝固过程以二相质点析出,易作为裂纹源增加硫化物偏聚;同时,两炉三机不均衡生产、控硫工装不配套、吹氩直上钢质量差等问题造成拉速与w(S)的不稳定,加剧了内质的恶化,造成铸坯严重的裂纹和偏析,热轧后不能完全轧合,焊接热影响区硫化物又重新熔融聚集延流线冷却成片层状分布,造成焊缝处材料不连续和焊接方向的应力集中。针对该问题,结合金相、低倍等检测结果采取针对性措施,在材料端进行优化,彻底解决了该质量问题。The Q235B-Z hot coil produced by a steel factory has a quality problem of batch flattening and cracking during the processing of HFW welded pipe.Through analysis,it is found that aluminum oxide inclusions in steel precipitate as two-phase particles during solidification,which is easy to increase sulfide segregation as a crack source.At the same time,the unbalanced production of two furnaces and three machines,the mismatched sulfur control tooling,and the poor quality of argon blowing straight steel,resulting in the instability of the casting speed and w(S),exacerbating the deterioration of the internal quality,resulting in serious cracks and segregation of the casting slab,which can not be fully rolled after hot rolling,and the sulfide in the welding heat affected zone is remelted and gathered again,and the strip is cooled into a layered distribution,resulting in the discontinuity of the material at the weld and the stress concentration in the welding direction,which is the root cause of this problem.In response to this issue,targeted measures were taken based on metallographic and low magnification testing results,and optimization was carried out at the material end to completely solve the quality problem.

关 键 词：HFW焊管 压扁开裂 剪切分层 偏析 系统控硫 铸机精度 低倍 

分 类 号：TG441.7[金属学及工艺—焊接]