Investigation on fretting wear mechanism of 316 stainless steel induced by Ni dissolution during pre-immersion corrosion in the liquid lead-bismuth eutectic (LBE)

Heat transfer tubes in nuclear power plants are easily damaged by fretting wear. The fretting behaviour of the heat transfer tube related to the lead-bismuth eutectic (LBE) alloys needs to be investigated. In this work, the effect of pre-immersion corrosion in LBE of AISI 316 stainless steel on fretting behaviour is explored in detail. Following short-duration corrosion (specimens denoted C0 and PC1), no significant change occurred during corrosion, and after the fretting test, the wear scars were shallow, with adhesive wear being the dominant wear mechanism. Following long-duration corrosion (specimens denoted PC2 and PC3), the dissolution of Ni and the formation of an oxide layer were the main corrosion mechanisms. After the fretting tests, the wear scars were deep, demonstrating a degraded anti-wear property, and fretting fatigue wear was dominant. The degradation of the fretting wear resistance in specimens PC2 and PC3 can be attributed to the absence of the protection of NiO in the tribolayer, the large grain size, and the weak plastic deformation accommodation ability. The underlying mechanism is the dissolution of Ni induced by pre-immersion corrosion in the LBE. The present work provides useful information on the fretting behaviour of heat-transfer tubes in nuclear power plants related to the LBE environment.