对P91管坯穿管后部分钢管的不同部位出现分层缺陷的原因进行了分析.结果表明:P91钢管中存在的分层缺陷,是管坯中富含铝、硅、钙、氧等元素的外来复合夹杂物断续地分布在管坯的不同部位,在随后的热加工过程中,由于外部应力作用导致较大的变形,使夹杂物沿周向、切向及径向延伸扩展,连接成较大面积从而导致分层缺陷的产生.

The reasons for lamination defect which appeared at different positions of the pierced P91 steel billet were analyzed.The results show that the lamination defect was caused by the foreign composite inclusions containing elements such as Al,Si,Ca,O,which distributed at different positions of the steel billet continuously.During the following heat treatment,a large deformation could be caused by the external stress,and then the inclusions would have a circumferential,tangential and radial extending and become a large area,which would lead to the lamination defect.