Evaluation of Lamination Defect of Seamless Steel Pipe

It is identified that the lamination defect of the seamless steel tube produced with the continuously- cast round billet is in fact abnormal inclusions existing in the tube wall middle area and near inside surface area. Such inclusions includes matters as deoxidation products of liquid steel formed during the melting and casting processes, and molten slag trapped in the hot metal, eroded refractory and protective slag which failed to float up to be skimmed and thus remained in the steel. The lamination defect can be identified by means of the ultrasonic thickness gauge or the ultrasonic detector. It is always the case that there exist lots of bulges and fins on the inner surface of a steel pipe bearing lamination defects. Producers for CC rounds as prepared for tube rolling are obligated to make sure that seamless steel tubes as rolled from their products will be free of lamination defects as originated during the steel melting and casting processes.