z向钢厚度1/4部位焊接裂纹成因及控制

Causes and control of welding cracks in the 1/4 thickness part of z-direction steel

针对南阳汉冶特钢有限公司生产的Q345DZ25钢板厚度1/4部位焊接裂纹缺陷,采取金相、电镜及能谱分析,发现裂纹部位主要是铝钙的氧化物夹杂所致。通过对钙处理工艺研究,环节取样进行成分、炉渣检测,得出造成钢水中铝钙氧化物夹杂含量高与生产过程中钙处理时机不合适有关。通过调整钙处理时机,控制钙线加入量,保证钢水中w_([Ca])/w_([Als])=0.10~0.14,改善了钙化处理效果,提高了钢水洁净度。

In view of the defects of welding cracks in 1/4 thickness of Q345 DZ25 steel plate produced by nanyang hanye special steel Co.,Ltd.,metallographic,electron microscope and energy spectrum analysis were conducted,and it was found that the cracks were mainly caused by oxide inclusion of aluminum and calcium.Through the study of calcium treatment process and the sampling of components and slag,it was concluded that the high content of aluminum and calcium oxide inclusions in molten steel were related to improper calcium treatment timing in the production process.By adjusting the time of calcium treatment and controlling the amount of calcium line,w[Ca]/w[Als]=0.10-0.14 in the molten steel,the calcification treatment effect was improved and the purity of molten steel was improved.