湿H_2S及Cl^-环境下FV520B不锈钢的应力腐蚀行为研究  

Stress Corrosion Cracking Behavior of FV520B Stainless Steel Exposed to Aqueous H_2S + Cl^- Environment

作　　者：魏仁超 陈学东[1,2] 范志超[2] 聂德福[2] 吴乔国[2] 金有海[1] 

机构地区：[1]中国石油大学(华东)化学工程学院,山东青岛266580 [2]合肥通用机械研究院,安徽合肥230001

出　　处：《流体机械》2017年第1期1-7,共7页Fluid Machinery

基　　金：国家重点基础研究发展计划(973计划)项目(2012CB026003)

摘　　要：采用慢应变速率拉伸试验研究了FV520B马氏体沉淀硬化不锈钢在湿H_2S、NaCl及湿H_2S+NaCl腐蚀环境下的应力腐蚀开裂敏感性,并讨论了介质浓度对应力腐蚀行为影响。结果表明:FV520B钢在湿H_2S+NaCl环境中的应力腐蚀敏感性最大,随H_2S浓度升高,FV520B钢抗拉强度和断后延伸率降低,应力腐蚀敏感性增大。FV520B钢在湿H_2S+NaCl腐蚀环境的恒位移加载应力腐蚀试验表明:湿H_2S+NaCl腐蚀介质能够显著降低FV520B钢的断裂韧性,随H_2S浓度升高,应力腐蚀临界应力强度因子KISCC减小;试样断口形貌分析表明,在湿H_2S+NaCl腐蚀介质中SCC试样断口呈准解理形貌,为氢脆型应力腐蚀开裂,Cl-具有一定的诱导促进作用。Stress corrosion cracking（ SCC） susceptibility of FV520 B martensitic precipitated hardening stainless steel exposed to aqueous hydrogen sulfide solution,sodium chloride solution and aqueous hydrogen sulfide containing with 5% sodium chloride solution were investigated by slow strain rate tensile test. The influence of hydrogen sulfide concentration was also taken into account. FV520 B stainless steel in aqueous hydrogen sulfide containing with 5% sodium chloride solution revealed a higher susceptibility to SCC than that exposed to other two mediums; the susceptibility increases with increasing of the concentration of hydrogen sulfide. Scanning electron microscopy analyses showed that the fracture of SSRT was transited from cavity fracture to brittle fracture when the concentration of H2S increased. The constant displacement stress corrosion tests of FV520 B steel exposed to aqueous hydrogen sulfide with chloride displayed that the fracture toughness of FV520 B significantly decreased due to the influence of corrosive medium and threshold stress intensity factor（ KISCC） of FV520 B decreases with the concentration of hydrogen sulfide increasing. Fracture morphology analyses showed that the fracture was characterized by quasi-cleavage and the SCC mechanism of FV520 B stainless steel exposed to aqueous hydrogen sulfide with chloride is hydrogen embrittlement（ HE） type of SCC.

关 键 词：FV520B马氏体沉淀硬化不锈钢 应力腐蚀开裂 H2S腐蚀 

分 类 号：TH45[机械工程—机械制造及自动化] O346.2[理学—固体力学]