레이저 쇼크 피닝에 의한 2205 듀플렉스 스테인리스강의 표면 경도 향상과 표면 변화 관찰

Improvement of Surface Hardness of 2205 Duplex Stainless Steel by Laser Shock Peening and Observations of Surface Changes

This work reports the results for laser shock peening of duplex stainless steel (22% Chromium - 5% Nickel) using a pulsed Nd:YAG laser (wavelength = 532nm, pulse width = 8ns). for the application to high-capacity pumps for seawater desalination plants. By properly selecting the process parameters such as laser intensity of 10GW/cm2, laser pulse density of 75pulse/mm2, and 100μm thick aluminum foil as an absorbent coating layer, the surface hardness of duplex stainless steel could be enhanced by 26%, from 256HV to 323HV with little changes in surface morphology and roughness. The depth of laser shock peened layer was measured to be around 2mm. The large enhancement of surface hardness is considered to have high practical importance in minimizing abrasive and corrosive deterioration of pump parts.