METHOD FOR PRODUCE A TUBE-SHAPED SEMI-PRODUCT

Abstract

The invention relates to a method for producing a seamless and hot-rolled tubular semi-finished product by means of the following steps: a) producing a billet from a steel alloy consisting of, in wt. percent, and optionally residual iron as well as melting-related impurities and accompanying elements, wherein the ratio Mn to S is 3.3:1 to 30:1 in wt. percent; b) cutting the billet into blocks; c) forming the block into a hollow block at a temperature of at least 1.000°C by punching with a punch press and subsequent elongation with reduction of the wall thickness and outer diameter by skew rolling or by simultaneously punching and elongating the block by a skew rolling process using an internal mandrel; d) lengths of the hollow block in the warm state at a temperature of at least 750 °C; e) final rolling without an internal mandrel and at a temperature of 850 °C to 1200 °C, to adjust the final geometry of a tubular semi-finished product, wherein the final rolling is carried out after an optional intermediate heating step and wherein a final temperature after rolling is in the range of 740°C to 1150 °C.