Effect of Fine Particle Peening on Oxidation Resistance of Austenitic Stainless Steel

概要

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Fine particle peening (FPP) treatment was introduced to improve the oxidation resistance of austenitic stainless steel. After FPP treatment, oxidation tests were performed at 700 and 800 °C for 1, 4 and 12 h in an atmospheric environment. The surface microstructures of the oxidized specimens were observed using optical microscopy, scanning electron microscopy (SEM), glow discharge optical emission spectroscopy (GD-OES), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The amount of oxygen diffused into the FPP-treated specimens was significantly less than that into un-peened specimens. Iron oxides were formed in the un-peened specimens as a result of the oxidation tests. In contrast, a protective chromium oxide layer was created on the FPP-treated surface, because the fine grains and dislocations induced by FPP treatment accelerated the diffusion of chromium during the subsequent oxidation tests. These results indicate that FPP treatment is a very efficient process to improve the atmospheric oxidation resistance of austenitic stainless steel.