Stress Corrosion Cracking of Alloy 182 Weld in H2SO4 Solution

• Main Authors: Chen-Hao Yang, 楊鎮豪
• Other Authors: Wen-Ta Tsai
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/93344959606185250615

碩士 === 國立成功大學 === 材料科學及工程學系碩博士班 === 94 === Abstract The effects of applied potential, strain rate, heat treatments and thioacetamide (CH3CSNH2) on the environmentally-assisted crack (EAC) or stress corrosion cracking (SCC) behavior of Alloy 182 weld in 0.05M sulfuric acid solution were investigated. Slow strain rate tests (SSRTs) were employed to evaluate the SCC resistance. The experimental results showed that Alloy 182 weld, without heat treatment, was most susceptible to EAC in the active-to-passive potential range. The SSRT results also demonstrated that, for the as-weld Alloy 182, the EAC resistance decreased with decreasing strain rate when the specimens were strained at -85mVSCE. Furthermore, in 0.05M H2SO4 solution and at -85mVSCE, the SSRT results showed that stress-relief (SR) heat treatment at 650℃ for 24h would cause an increase in the EAC susceptibility, where solution annealing (SA) at 1100℃ for 0.5h gave rise to an increase in EAC resistance as compared with that of the as-weld Alloy 182. The addition of CH3CSNH2 caused accelerated corrosion of all the Alloy 182 welds in 0.05M H2SO4 solution. Though an enhanced corrosion was observed, SCC was not observed with the addition CH3CSNH2 in the sulfuric acid solution.