热效应所致析出相对2205双相不锈钢耐蚀性的影响

The effect of precipitated phases causded by thermal effect on the corrosion resistance of 2205 duplex stainless steel

研究不同热效应下2205双相不锈钢的析出相类型和特点,通过测试固溶态和不同热效应下2205双相钢的动电位极化曲线、电化学阻抗谱以及动电位扫描后试样表面形貌的观察,研究析出相对其耐腐蚀性能的影响。结果表明:固溶态材料的耐腐蚀性能及再钝化性能最好;而在850℃时效后,由于χ和σ相析出含量增多,在过电位下会由点蚀转变为选择性腐蚀,导致材料的耐腐蚀性能下降最严重;900℃时效后,2205双相不锈钢中的析出相含量降低,其耐腐蚀性能的下降有所缓解。

The research studied the types and characteristics of precipitated phases of 2205 duplex stainless steel under different thermal effects.The effect of these phases on the steel s corrosion resistance was tested by analyzing the potentiodynamic polarization curve,electrochemical impedance spectroscopy,and surface morphology after potentiodynamic scanning of the steel specimen in both solid-solution state and under different thermal effects.The results showed that the solid-solution material exhibited the best corrosion resistance and repassivation performance.The corrosion resistance of the material was most severely reduced due to the highest content ofχandσprecipitates after aging at 850℃,and it changed from pitting to selective corrosion under over potential.After aging at 900℃,the decline of corrosion resistance of the steel was alleviated as a result of the reduced precipitated phase content.