A study on the formation of plastic deformation layer in the steam generator tube materials during fretting wear

The wear test of steam generator (SG) tube materials against ferritic stainles steels has been performed to evaluate the wear mechanism in water environment. It is difficult to observe the wear particle layers that are frequently formed in air environment. So the wear rate of SG tube materials in water environment depends on the change of mechanical properties between contact surfaces during fretting test. From the result of the subsurface hardness test, Inconel 690 has high hardness value than Inconel 600 as close to surface and this means that energy must be consumed in the contact surface of Inconel 690 to plastically deform the same volume. Main cause of hardness variation is due to the difference of the stacking fault energy with the chromium content. Besides, the deviation of wear coefficient in the Work-rate model was explained by the change of friction coefficient during fretting wear