METHOD FOR RELIEVING RESIDUAL STRESS FROM ROTOR OF TURBINE

摘要

PURPOSE:To relieve residual welding stress from a rotor by coating the shaft of the rotor with a metal different from the material of the shaft by build-up welding and by coating the metal with =1 layers of an alloy having a high coefft. of thermal expansion such as an austenitic alloy by build-up welding. CONSTITUTION:The bearing part of the shaft 1 of a rotor is coated with carbon steel 2 by build-up welding in the circumferential direction by a prescribed length, and the steel 2 is coated with an austenitic alloy 3 by build-up welding. The whole shaft 1 or only the weld zone of the shaft 1 is subjected to stress relieving annealing in accordance with the materials. When a shaft made of 12Cr steel is coated with carbon steel by build-up welding, stress relieving annealing is carried out at 620+ or -25 deg.C for about 20hr. The outermost layer of the alloy 3 is then shaved off by mechanical working.