Patent ID: 9677692
Date: 2017-06-13
CPC Classifications: B21C,B23K,F16L

Claim:
1. A welded steel pipe, the seam of which is joined by high-energy-density beam welding, comprising: a seam on an outer side and an inner side of the welded steel pipe, the seam being worked so as to be smooth by cutting; and a repaired seam on an inner side of the welded steel pipe, the repaired seam being formed by remelting and solidifying a region of the seam on the inner side of the welded steel pipe, wherein the repaired seam on the inner side has a depth of from 0.5 mm to 40% or less of the wall thickness of the welded steel pipe, and a width in a range of two to five times the width of the seam on the inner side of the welded steel pipe, and the center line of the seam coincides with the center line of the repaired seam.