The infolding in N80 grade microalloyed seamless pipe steels was analyzed by microscopic test,SEM and chemical composition analysis of slag inclusion.

• N80级微合金非调质无缝钢管在生产中出现内折缺陷。采用金相检验、夹渣物的化学成分分析及扫描电镜观察等方法对该缺陷进行了分析。