冷作变形量对Super304H不锈钢耐蚀性能的影响

Effect of Cold Deformation on Corrosion Resistance of Super 304H Stainless Steel

Super304H奥氏体不锈钢性能优异,应用广泛,但目前鲜见其冷作变形后腐蚀行为的研究报道。采用化学浸泡法、电化学方法、能谱分析等研究了冷作变形量对Super304H奥氏体不锈钢耐蚀性能的影响。结果表明:在6%FeCl3+0.05 mol/L HCl混合溶液中,随着变形量的增加,Super304H不锈钢的腐蚀速率先降低后增加,变形量为15%时,腐蚀速率最低;在25℃,3.5%NaCl溶液中,随着变形量的不断增大,Super304H不锈钢耐蚀性能先增强后减弱,变形量为15%时,交流阻抗谱阻抗值最大,耐点蚀性能最好;在55℃,3.5%NaCl溶液和25℃,3.5%NaCl+2.0%H2SO4溶液中,随着变形量的不断增大,耐蚀性能先增强后减小,变形量为18%时,阻抗值最大,Super304H不锈钢耐点蚀性能最好;在6%FeCl3+0.5 mol/L HCl混合溶液中,Super304H不锈钢点蚀孔周围Fe和Ni的含量比远离蚀孔区域的低,腐蚀产物以Fe_2O_3为主。

The effect of cold deformation on corrosion resistance of super 304H stainless steel was studied by chemical immersion method, electrochemical test and EDS. Results showed that： in 6% FeCl3＋0.05 mol/L HCl mixed solution, the corrosion rate of super 304H stainless steel decreased firstly and then increased with the increase of the deformation, and reached the lowest value when the deformation was 15 %. With the increase of deformation, the corrosion resistance increased firstly and then decreased in 3.5 % NaCl solution at 25 ℃ and when the deformation was 15%, the impedance value reached the maximum and the stainless steel had the best pitting corrosion resistance. In 3.5% NaCl solution at 55 ℃ and in 3.5%NaCl＋2.0%H2SO4 solution at 25 ℃, the corrosion resistance had the similar changing trend： first increased and then decreased, and the impedance reached the maximum value when the deformation was 18%, presenting the best pitting corrosion resistance. Besides, in 6%FEC13＋0.5 mol/L HCl solution, the contents of Fe and Ni around the pitting holes were much lower than those at the remote areas, and Fe203 was the main corrosion product .