Patent ID: 6880220
Filing Date: 2005-04-19
Classification: B23K,F16L,Y10T

Abstract:
1. A method of manufacturing a welded seamless PIPE formed at least in part of a corrosion resistant and/or erosion resistant alloy, the method comprising the steps of: manufacturing an ultrasonic inspected defect free finished plate of a corrosion and/or erosion resistant alloy; forming a hollow having a wall thickness, a length and a longitudinal seam region by feeding the finished plate through a high speed roll forming mill; welding the hollow along the longitudinal seam region using a tungsten inert gas or plasma welding process, achieving complete weld penetration through the wall thickness of the hollow with a similar filler material of like chemistry to the chemistry of the parent metal or without the use of a filler material; ultrasonically inspect with multiple probes to insure the hollow's full-length weld seam is free of defects that exceed specifications; rolling, flattening or forging the entire length of the hollow's weld seam; full body anneal the weld heat affected zone to attain a homogenous through wall structure; pickle or blast the welded hollow to remove oxide buildup from the annealing process; cold work the welded low yield and tensile strengths hollow to reduce the welded hollow in wall thickness and in outer and inner diameters, thereby producing a high yield and tensile strengths cold worked PIPE; full body ultrasonic inspection with multiple probes to insure the finished PIPE is free of defects that exceed specifications.