RESIDUAL STRESS IMPROVEMENT OF TURBINE ROTOR

摘要

PURPOSE:To dissipate a residual tensile stress on the external surface of a part where a journal of 12% chromium steel rotor is padded with low alloy steel by mechanically applying a compressive force to the external surface of the journal part so as to give a residual compressive stress. CONSTITUTION:The journal part 1a of a 12% chromium steel rotor 1 is padded with a low alloy steel 2 or the like. With said rotor 1 turned slowly, a roller 5 is pressed onto the external surface of the low alloy steel 2 or the like to compress the surface of the journal part 1a, thereby reproducing a residual compressive stress or reducing a residual tensile stress. The residual tensile stress may promote creation and growth of a fatigue crack while the residual compressive stress may be an extremely effective means for restricting them so as to improve the strength. The method as above may dissipate the residual tensile stress on the surface of the journal part 1a and improve the residual stress of a turbine rotor.