Method for producing a welded steel pipe

摘要

A method for producing an electric-resistance-welded steel pipe comprises the steps of: (a) forming a steel strip having two edges into a cylindrical form so that the two edges face each other; (b) preheating the two edges of the steel strip to a temperature of a melting point or less by applying a high frequency electric current to the two edges; (c) pressing the two edges of the steel strip each other by using squeeze rolls to form a joint portion; (d) irradiating a high density energy beam sufficient to fuse a full thickness of the steel strip to a portion adjacent to a squeeze point to weld the the joint portion; (e) controlling a upset using the squeeze rolls enough to reduce a weld defect.