Abstract: A process of producing an austenitic stainless steel tube comprises the steps of: a) producing an ingot or a continuous casted billet of the austenitic stainless steel, b) hot extruding the ingot or the billet obtained from step a) into a tube, c) cold rolling the tube obtained from step b) to a final dimension thereof. The outer diameter D of the cold rolled tube is 70-250 mm and the thickness t thereof is 6-25 mm, and the cold rolling step is performed such that the following formula is satisfied: (2.5×Rc+1.85×Rh?17.7×Q)=(Rp0.2target+49.3?1073×C?21Cr?7.17×Mo?833.3×N)±Z??(1) wherein Rp0.2target is targeted yield strength and is 750?Rp0.2target?1000 MPa, 30?Rc?75%, 50%?Rh?90%, 1?Q?3.6, and Z is 65.

Abstract: A process of producing a duplex stainless steel tube comprises the steps of: a) producing an ingot or a continuous casted billet of said duplex stainless steel; b) hot extruding the ingot or the billet obtained from step a) into a tube; and c) cold rolling the tube obtained from step b) to a final dimension thereof. The outer diameter D and the wall thickness t of the cold rolled tube is 50-250 mm respectively is 5-25 mm, and, for the cold rolling step, R and Q are set such that the following formula is satisfied: Rp0.2target=416.53+113.26·log Q+4.0479·R+2694.9·C %?82.750·(log Q)2?0.04279·R2?2.2601·log Q·R+16.9·Cr %+26.1·Mo %+83.6·N %+Z??(1) wherein Rp0.2target is targeted yield strength and is 800-1100 MPa and 0<Q<3.6.

Abstract: Method of producing a tube of duplex stainless steel is disclosed. The steel comprises the following composition, in weight %: C max 0.03, Si max 1.0, Mn max 1.5, P max 0.05, S max 0.03, Cr 24-26, Ni 6-8, Mo 3.0-4.0, N 0.24-0.32. The method comprises steps of: forming a tube of the duplex stainless steel, cold working the tube obtained from the step of forming a tube, and soft annealing the tube after the step of cold working by subjecting the tube to a temperature, T, within a range of 500-750° C. for a time period, t, of 0.5-5 minutes.

Abstract: A method for manufacturing a tube includes continuously moving a tubular hollow blank through an expansion tool, and supplying fluid to a space delimited by the expansion tool and the tubular hollow blank the such that a hydraulic pressure is applied inside the tubular hollow blank. The magnitude of the hydraulic pressure is selected such that the tubular hollow blank is deformed plastically. The disclosure also relates to an arrangement for manufacturing a tube.

Abstract: A process of producing an austenitic stainless steel tube comprises the steps of: a) producing an ingot or a continuous casted billet of the austenitic stainless steel, b) hot extruding the ingot or the billet obtained from step a) into a tube, c) cold rolling the tube obtained from step b) to a final dimension thereof. The outer diameter D of the cold rolled tube is 70-250 mm and the thickness t thereof is 6-25 mm, and the cold rolling step is performed such that the following formula is satisfied: (2.5×Rc+1.85×Rh?17.7×Q)=(Rp0.2target+49.3?1073×C?21Cr?7.17×Mo?833.3×N)±Z ??(1) wherein Rp0.2target is targeted yield strength and is 750?Rp0.2target?1000 MPa, 30?Rc?75%, 50%?Rh?90%, 1?Q?3.6, and Z is 65.

Abstract: A process of producing a duplex stainless steel tube comprises the steps of: a) producing an ingot or a continuous casted billet of said duplex stainless steel; b) hot extruding the ingot or the billet obtained from step a) into a tube; and c) cold rolling the tube obtained from step b) to a final dimension thereof. The outer diameter D and the wall thickness t of the cold rolled tube is 50-250 mm respectively is 5-25 mm, and, for the cold rolling step, R and Q are set such that the following formula is satisfied: Rp0.2target=416.53+113.26·log Q+4.0479·R+2694.9·C %?82.750·(log Q)2?0.04279·R2?2.2601·log Q·R+16.9·Cr %+26.1·Mo %+83.6·N %+Z??(1) wherein Rp0.2target is targeted yield strength and is 800-1100 MPa and 0<Q<3.6.

Abstract: A method for manufacturing a tube includes continuously moving a tubular hollow blank through an expansion tool, and supplying fluid to a space delimited by the expansion tool and the tubular hollow blank the such that a hydraulic pressure is applied inside the tubular hollow blank. The magnitude of the hydraulic pressure is selected such that the tubular hollow blank is deformed plastically. The disclosure also relates to an arrangement for manufacturing a tube.