Patent ID: 9745642
Date: 2017-08-29
CPC Classifications: C21D,C22C,C22F,F16L,F22B,G21C,G21D

Claim:
1. A method for heat treating a metal tube or pipe, comprising: heat treating a metal tube or pipe which is accommodated in a heat treatment furnace, the metal tube or pipe being laid down on a plurality of cross beams, the plurality of cross beams being arranged along a longitudinal direction of the metal tube or pipe such that a distance between adjacent ones of the cross beams is in a range of 200 to 2500 mm, the metal tube or pipe being in contact with the cross beams, wherein as the cross beams, cross beams having a convex top surface are used, the convex top surface having a radius of curvature in a range of 50 to 300 mm.