| 摘要 |
PURPOSE:To decrease the residual stress in the welded joint part of metallic materials by heating both sides of the welded joint part and cooling forcibly the welded joint part to a specific temp. by a low temp. liquefied gas. CONSTITUTION:Metallic materials A1, A2 are butt-welded along a weld line M and thereafter both sides 2, 2' of the welded joint part 1 where the residual compressive stress exists are heated to the lowest possible temp., more preferably to about <=200 deg.C by the flame for heating radiated from nozzles 3, 3'. At the same time, a coolant 5 such as liquid nitrogen or the like stored in a storage tank 4 is sprayed along te weld line M of the part 1 via a valve 6 and a flexible pipe 7 from a spraying pipe 8 to cool forcibly the periphery of the part 1 to <=0 deg.C. A cover 9 is preferably provided to keep the places except the part to be cooled free from the jet 9 of the coolant 5. |
