Induction heating method and apparatus for relieving residual stress in welded joint between main and branch pipes

摘要

A heating method and heating apparatus for uniformly or substantially uniformly heating a predetermined portion of main and branch pipes including a welded joint therebetween of a main-and-branch-pipe assembly, thereby relieving the residual stress in the welded joint between the main and branch pipes. The defects and problems encountered in the conventional residual-stress-relief treatment processes can be substantially overcome such as complication in winding fabrication at the branch pipe which results in bad control of temperature a mock-up test being needed for fabrication of an inductor and existence of a non-heated zone resulting in unbalance of the stresses so that the effects of the residual stress-relief treatment are reduced.