Effect of test duration on impact/sliding wear damage of 304L stainless steel at room temperature: metallurgical and micromechanical investigations

The control-rod cluster assemblies (RCCAs) can be damaged by impact-sliding wear due to flow-induced vibrations which generate contacts with their guidance devices (RCC guide tube). Impact/sliding methodological wear tests have been performed at room temperature on stainless steel claddings (304L). Only the duration variable has been selected to evaluate the wear effect on the material (other experimental conditions have been fixed for all tests). Some non-destructive examinations have been performed on the worn specimens, using weighing, scanning electron microscopy and 2D profilometry. The results show clearly a sensitive damage of the two contacting bodies. X-ray diffraction measurements have been made in order to follow the evolution of the initial microstructure and micromechanical state of the 304L stainless steel (strain-hardening, residual stresses and phase transformation induced by plasticity). The use of these techniques show that test duration has no effect on the behavior of material even if wear damage continues to progress. So these data brought us to the fore that the main wear mechanism at room temperature is an oxidation of the surface layers followed by an oxides detachment stage due to the impact-sliding motion.