Stress Corrosion Behavior of 316L Stainless Steel Hydraulic Control Pipeline in Heavy Oil Thermal Recovery Service Environment

Thermal stress distribution of 316L stainless steel hydraulic control pipeline at 200-350 ℃ was simulated by finite element analysis software Ansys Workbench. And then combining with the results of high temperature corrosion simulation test, the stress corrosion behavior of the hydraulic control pipeline was studied in heavy oil thermal recovery service environment. The results show that the maximum thermal stress of the hydraulic control pipeline in the temperature range of 200-350 ℃ appeared in the area close to the tubing coupling side, and its value increased with increasing temperature. Several radial cracks existed in the tensile area of the hydraulic control pipeline under stress loading condition, and some pittings were observed in the local area under non-stress loading condition. The failure mechanism of hydraulic control pipeline in the heavy oil thermal recovery service environment was that anodic dissolution occurred at pittings and then stress corrosion cracks were initiated under combination of thermal stresses and corrosive mediums.