Evaluation of pipe wall thinning phenomenon by the high temperature impactfretting testing
佐藤 善紀 Yoshiki SATO 岩渕 明 Akira IWABUCHI 内館 道正 Michimasa UCHIDATE 八代 仁 Hitoshi YASHIRO
CorrosionLiquid droplet impingementNuclear reactorPipe wall thinningStainless steelWear
In this paper, to study the wear properties of the pipe materials for the nuclear power stations, a high temperature impact fretting testing was carried out. Employing two piezo actuators, impact fretting test rig can generate impact fretting under various impact loads, fretting amplit udes and frequencies. It also enables us to control water temperature, dissolved oxygen and water pressure. AISI type 304 stainless steel, which is used as a pipe material in nuclear power stations, was used as specimens. Alumina balls were used as the counter materials. We studied th e effects of impact frequency and temperature on wear of the steel disks. Results of experiments have shown that wear was strongly affected by the chemical factors. Especially, water temperature and frequency were significant in the analysis of the wear depth. The wear depth increases with decreasing impact frequency under same number of cycles. And the growth of oxide conforms to parabolic oxidation law. Therefore, we suggest a need for considering the effect of chemical factors for the prediction of the pipe wall thinning phenomenon by liquid droplet impingement.