현가용 SUP-9강의 1차, 2차 쇼트피닝에 의한 부식특성

Abstract

The compressive residual stress, which is inducing by shot peening process, has the effect of increasing the intrinsic fatigue strength of surface and therefore would be beneficial in reducing the probability of fatigue damage. However, it was not known that the effect of shot peening in corrosion environment. The difference of the weight loss between shot peening material and unpeening material was big in the beginning of the corrosion, but as time passed by, the difference got smaller and in the end got steady. Shot peening material was found to have more resistant strain to corrosion evironment than unpeening material. This estimates that Compressive residual stress, which is formed on the surface of the material in processing shot peening, acts as protective coating film when corrosion progresses. In this study, the influence of shot peening and corrosion condition for corrosion property was investigated on immersed in supply water, 1% NaCl, 1% H2SO4. The immersion test was performed with two kind of specimen. The immersion periods was performed 8640hour(360days). Corrosion potential, weight loss were investigated from experimental results. From test results, the effect of shot peening on the corrosion characteristics was evaluated.