50Mn18Cr4WN Retaining Ring Macro Residual Stress Relieving By Pulsating Oil Pressure

摘要

In the article, the method of the macro residual stress relieving by pulsating hydraulic test on 600MW turbogenerator retaining ring is described. The method is valid for macro residual stress relieving and doesn't damage the mechanical properties of the turbogenerator retaining ring. In the test, macro residual stress decreased by 240MPa and dimension of the retaining ring diameter changed notably. The retaining ring was sealed. Oil pump injected oil into sealed retaining ring. The highest pressure is 100MPa,circulated 16 times. The macro residual stresses were measured by the method of cutting stress relieving ring before and after test. A large microcallipers measured the diameter change in 90° direction before and after test. By 16 times tests the macro residual stresses decreased notably, by about 50%. The diameter of the retaining ring changed notably too, by about 3mm. The mechanism of the macro residual stress relieving by pulsating hydraulic test on turbogenerator retaining ring is discussed. The "double-dynamic mechanism" is introduced to explain the course of macro residual stress relieving in the test.