316L不锈钢TIG焊接接头在H_2S溶液中的钝化性能  

Passivation Behavior of TIG Welded Joints of 316L Stainless Steel in Solutions with Different Concentrations of H_2S

作　　者：卢向雨[1,2] 姚胜[1] 唐俊荣 赵刘明 冯兴国[3] 

机构地区：[1]江苏科技大学材料科学与工程学院,江苏镇江212003 [2]材料腐蚀与防护四川省重点实验室,四川自贡643000 [3]河海大学港口海岸与近海工程学院,南京210098

出　　处：《表面技术》2015年第12期6-11,共6页Surface Technology

基　　金：国家自然科学基金(51301060);江苏省高校自然科学研究项目(14KJB430012);材料腐蚀与防护四川省重点实验室开放基金(2015CL08)~~

摘　　要：目的研究316L不锈钢TIG焊接接头各区域在不同浓度H2S溶液中的钝化及耐蚀性能差异。方法在H_2S质量浓度为0.05,0.1,0.2,0.4,0.8 g/L的H2S溶液中,通过极化曲线、恒电位阶跃、阳极极化、交流阻抗等方法,分别研究316L奥氏体不锈钢TIG焊接接头的母材区和焊缝区的钝化性及耐蚀性能。结果随着H_2S浓度的增加,焊接接头母材区和焊缝区的钝化性能都所有降低,电化学活性都明显升高,且腐蚀电位逐渐降低,腐蚀电流密度有所增加。交流阻抗拟合结果显示,母材区和焊缝区的抗腐蚀性能指标(R1+R2)随着H_2S浓度的升高而降低。此外,在相同浓度的H_2S溶液中,焊缝区的腐蚀电位、钝化性能、阻抗都比母材区低,而电化学活性、腐蚀电流密度都比母材区高。同时,随着H2S浓度的升高,焊缝区与母材区的钝化性能、耐腐蚀性差距逐渐变大。结论随着H_2S溶液浓度的增加,316L不锈钢TIG焊接接头母材区和焊缝区的钝化性能逐渐降低,耐蚀性下降,且二者耐蚀性的差距逐渐加大。在相同浓度的H_2S溶液中,母材区的耐蚀性比焊缝区好。Objective To study the difference in the passivation and corrosion behavior of tungsten-arc inert gas （TIG） welded joints of 316L stainless steel in different concentrations of H2S solutions. Methods In 0. 05 ,0.1,0. 2 ,0. 4,0. 8 g/L H2S solutions, the passivation behavior and corrosion resistance of the base material and the welded zone in TIG joints were investigated by polarization curves, potential step, potentiostatic polarization, and electrochemical impedance spectroscopy （EIS）. Results As the concentrations of H2S increased, the passivity and corrosion potentials decreased, while the activity and corrosion current densities increased. The fitting results of EIS showed that （ R1 ＋R2 ） of the base material and the welded zone in TIG joints decreased with the increased concentrations of H2S. Meanwhile, the welded zone presented lower corrosion potential, passivity, impedance and higher electrochemical activities and corrosion current densities than the base material at the same concentration of H2 S. Furthermore, the resuhs also suggested that the difference of corrosion resistance between welded zone and base material became significant with the increasing concentration of H2S. Conclusion As the concentration of H2S increased, the passivation and corrosion resistance of the base material and the welded zone in TIG joints decreased and the difference of corrosion resistance between them became significant. The base material presented higher corrosion resistance than the welded zone at the same concentration of H2S.

关 键 词：316L不锈钢 钨极惰性气体保护焊 硫化氢溶液 腐蚀 钝化 

分 类 号：TG142.7[一般工业技术—材料科学与工程] TG172.6[金属学及工艺—金属材料]