Effects of aging process on microstructure and corrosion resistance of 904L austenite stainless steel

Effects of aging process on microstructure and corrosion resistance of 904 L super austenitic stainless steel in H2SO4 and HF mixed solution were studied by means of optical microscope,SEM,EDS analysis and electrochemical tests. The results show that microstructure of 904 L stainless steel consists of austenite with a number of twins after solid solution and aging treatment. With the increase of the aging time,the corrosion current density increases and the impedance value decreases,at constant aging temperature,which means that corrosion resistance of 904 L stainless steel decreases. When 904 L austenite stainless steel aged at 760 ℃ for 1 h,the minimum corrosion current density is obtained and charge transfer resistance reaches the maximum value,i. e. the corrosion resistance of904 L austenite stainless steel in H2SO4 and HF mixed solution is optimal with the aging process.