文献类型：期刊文献

英文题名：Pit evolution around the fusion line of a NiCrMoV steel welded joint caused by galvanic and stress-assisted coupling corrosion

作者：Weng, Shuo[1];Huang, Yuhui[1];Xuan, Fuzhen[1];Yang, Fuqian[2]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Lab Pressure Syst & Safety MOE, Shanghai 200237, Peoples R China;[2]Univ Kentucky, Dept Chem & Mat Engn, Mat Program, Lexington, KY 40513 USA

年份：2018

卷号：8

期号：7

起止页码：3399

外文期刊名：RSC ADVANCES

收录：;EI(收录号：20180504690622);WOS:【SCI-EXPANDED(收录号:WOS:000423348500006)】；

基金：Supports from National Science Foundation of China (51325504, 51475167) and the Program of Shanghai Subject Chief Scientist (14XD1401300) are greatly acknowledged. The work reported here was partially funded by the Ministry of Education of China through a 111 Project.

语种：英文

外文关键词：Distribution functions - Tensile stress - Weibull distribution - Heat affected zone - Welding - Molybdenum steel - Sodium chloride - Welded steel structures - Molybdenum alloys - Chromium steel - Electrodes - Steel corrosion - Chromium alloys

摘要：The corrosion of NiCrMoV steel welded joints is performed in an aqueous solution of 3.5 wt% NaCl at 180 degrees C in a container at a pressure of 0.8 MPa. The specimens in the shape of cylindrical tensile rods are immersed in the aqueous solution under the action of tensile stress in a range of 0 to 0.9 of the yield stress of the base metal. The experimental results suggest that there is macro-galvanic corrosion in the welded joint with the coarse-grained heat affected zone (CGHAZ) as anode due to the highest corrosion susceptibility of the CGHAZ. The CGHAZ has the highest positive current density in the welded joints as measured by the scanning vibrating electrode technique. The two-parameter Weibull distribution function, which is represented by the Weibull modulus and characteristic strength, is used to analyze the distribution of the depth of pits at different immersion times. Both the Weibull modulus and characteristic strength are calculated, and found to be dependent on the applied tensile stress. The values of the characteristic pit depth and the average pit depth reveal that there are two mechanisms controlling the corrosion of the NiCrMoV steel welded joints; one is galvanic corrosion, and the other is stress-assisted corrosion.