氮对SUS301L不锈钢耐蚀性影响的探讨

EFFECT OF NITROGEN CONTENT ON CORROSION RESISTANCE OF SUS301L STAINLESS STEEL

采用电化学法、5%硫酸腐蚀试验、65%硝酸晶间腐蚀法和42%沸腾氯化镁法等对不同氮含量的SU301L不锈钢的耐点蚀、均匀腐蚀、晶间腐蚀和应力腐蚀性能进行了评价,探讨氮对亚稳定奥氏体不锈钢SUS301L耐蚀性影响的规律。试验结果表明:氮的加入提高了SUS301L不锈钢的耐点蚀性能,当氮含量在0.1%～0.15%内变化时,对材料的耐应力腐蚀能力无显著影响。适量的氮能有效阻碍晶界碳化铬的析出,提高SUS301L钢的耐晶间腐蚀性。当氮含量达到0.15%以上,晶界氮化铬的析出会造成SUS301L钢的耐晶间腐蚀性能的下降。

In order to find the regularity of nitrogen effect on corrosion resistance of SUS301L metastable austenitic stainless steel, the concosion resistance of three kinds of SU301L stainless steel with different nitrogen content was evaluated, including the pitting corrosion, uniform corrosion, intcrgranular corrosion and stress corrosion resistance. The test methods were electrochemical method, 5% H2SO4 corrosion, intergranular corrosion of 65% nitric acid and 42% boiling magnesium chloride method. The results showed that the nitrogen could improve the pitting potential of SUS301L in 3.5% NaC1 solution. When the nitrogen content increased from 0. 1% to 0. 15% , the stress corrosion resistance of materials had no obvious variation. Proper nitrogen content could prevent the formation of chromium carbon, so as to improve the resistance to intergranular corrosion of SUS301L. While the nitrogen content reached more than 0. 15% , the precipitation of chromium nitride on grain boundary would decline the intergranular corrosion resistance of SUS301 L.