低镍奥氏体不锈钢焊管开裂原因分析

Cracking Reason Analysis of Welded Pipe with Low-nickel Austenite Stainless Steel

通过对开裂样品进行化学成分、力学性能、金相组织、断口扫描电镜能谱分析及X射线衍射分析,探讨了用低镍奥氏体不锈钢制作焊管产生裂纹的原因。结果表明,焊管开裂的原因是材料未经固溶处理、晶界存在大量碳化物以及形变诱发产生大量马氏体所致。通过控制终轧温度(890℃),轧后快冷到700℃以下,可避免碳化物的大量析出,最好再进行热退火酸洗固溶处理。

In order to analyze the cracking reason of welded pipe with low-nickel austenite stainless steel, the chemical composition and mechanical properties of cracking simple were analyzed and the metallurgical structure, energy spectrum and fractography were tested with scanning electron microscope and X-ray diffraction analysis. The results showed that it is caused by the material without solution treatment, so lots of carbides on the grain boundary, and a large of martensite produced by deformation. Controlling the finishing roiling temperature （890 ℃）, and accelerating cooling to 700℃ after rolling can avoid a great deal of carbide precipitation. The solution treatment by annealing is the best measure.