Q345B热轧带钢冷弯开裂成因分析

针对热连轧厂生产的Q345B冷弯型钢用钢带在生产矩形管过程中出现的焊缝开裂、热影响区压扁开裂和弯曲弧开裂问题,通过对Q345B带钢成分、组织、夹杂物、气体、硫偏析等检验、分析以及对焊接工艺研究,得出焊接工艺不合理是造成焊缝开裂和热影响区压扁开裂的主要原因;原料中夹杂物多、带钢中存在的孔洞(或微裂纹)是造成弯曲弧开裂的主要原因。通过改进焊接工艺、减少钢中硫含量和提高钙处理效果等提高了矩形管合格率。

Analysis of Crack in Cold Bending of Q345B Hot Rolled Strip Steel

The chemical component , microstructure, inclusion, gas content, sulfur segregation and welding technology were analyzed and tested to solve the problems in production of Q 345B rectangular welded pipe , such as welded seam , heataffected zone and bend arc cracked etc .The conclusions were gained that unscientific welding technology induced welded joint crack and numerous inclusions was the cause of bend arc crack .After optimization of welding technology , and reduction of sulfur content and enhancement of calcium treatment effect , the qualified rate of rectangular pipe improved .