大管径厚壁低温碳钢管焊接裂纹控制措施

Control Measures for Welding Crack of Large Diameter and Thick Wall Low Temperature Carbon Steel Pipe

大管径厚壁低温碳钢管A333-Gr6焊接时易出现冷裂纹,主要是淬硬性、应力作用和扩散氢三种因素相互作用所致。首先通过打磨或碳弧气刨等方式对裂纹进行清除,随后对裂纹进行修复。为避免裂纹再次出现,从焊前预热、清理焊接区域、选择合适的坡口形式、有效的定位焊接、进行工装固定、焊接中断的处理及其焊后热处理消氢几个方面,对焊接过程进行控制,可有效消除焊接裂纹。

Cold cracks are easy to occur when A333-Gr6 low temperature carbon steel pipe with large diameter and thick wall is welded.It is mainly caused by the interaction of hardenability,stress and diffused hydrogen.First,remove the cracks by grinding or carbon arc gouging,and then repair the cracks.In order to avoid the recurrence of cracks,it can control the welding process,including preheating before welding,cleaning the welding area,selecting appropriate groove form,effective positioning welding,fixture fixing,treatment of welding interruption and hydrogen elimination after post welding heat treatment.