Patent ID: 9718116
Date: 2017-08-01
CPC Classifications: B21J,B21K

Claim:
1. A method for producing a hot-rolled, seamless pipe having optimized fatigue properties in the welded state, with an outside diameter of up to 711 mm and a nominal wall thickness of up to 100 mm, the pipe being made of steel, and having a pipe body with an inside diameter and an outside diameter and a pipe end, said method comprising the steps of: providing the hot-rolled, seamless pipe; increasing the outside diameter or decreasing the inside diameter, or both, of the hot-finished or hot-rolled pipe along a predetermined length of the pipe within predetermined tolerances to produce a region of the pipe end with a wall thickness greater than a wall thickness of the pipe body, the wall thickness being increased by at least 12 mm; and producing a desired pipe cross-section in the region with the greater wall thickness by mechanical machining so that a transition from the region of the pipe treated with the mechanical machining to a region of the pipe not treated with the mechanical machining is continuous and stepless with no surface roughness and is substantially notch-free, and wherein a residual wall thickness remaining in the treated region is within tolerances.