Q195L盘条闪光对焊接头开裂原因分析

Analysis on Cracking of Q195L Wire Rod Flash Butt Welded Joints

采用金相显微镜（OM）、扫描电子显微镜（SEM）及能谱仪（EDS）等试验设备分析了某批次Q195L盘条闪光对焊接头开裂的原因。结果表明,Q195L盘条闪光对焊接头开裂为明显的脆性开裂;开裂试样与正常试样对比,除S、N外,其余元素含量基本保持一致。在S含量相对较高的试样中产生了少量的Mn S,但并未引起焊接接头的脆断;N含量相对较高的试样晶界处易出现N的释放,引起裂纹的产生,导致焊接接头的脆断。

The cracking of flash butt welded joint of a batch of Q195 L wire rod was investigated by using optical microscope（OM）, scanning electron microscope（SEM） and energy disperse spectroscope（EDS）, etc. The results show that the cracking of the Q195 L wire rod flash butt welded joint is obvious brittle fracture. Compared with the normal sample, the contents of the elements of the cracking sample except S and N are basically consistent. A small amount of Mn S is generated in the sample with relatively high S content, but it does not result in brittle fracture of welded joint. The release of N is easy to occur at the grain boundary of the sample with relatively high N content, which leads to crack initiation and brittle fracture of the welded joint.