Effect of Local Fluid Disturbance Induced by Weld Reinforcement Height on the Corrosion of a Low Alloy Steel Weld

Abstract

Weld corrosion exists widely in the petrochemical industry and attracts great attention. Most research proves that weld corrosion originates from the material factors introduced during the welding process. However, it is noted that local fluid turbulence due to the weld reinforcement height (WRH) plays an important role in the non-uniform corrosion of welds in flowing media. Accordingly, the individual effect of the local flow on the weld corrosion of low alloy steel was analyzed by experiments and simulation in this study. Electrochemical measurements and morphology observation were conducted, combined with flow field analyses. The results showed that local fluid turbulence due to WRH affected the non-uniform corrosion of low alloy steel welds. The upstream surface and the backflow surface had the highest and lowest corrosion rates, respectively. Interestingly, the high flow velocity surface region did not have a high-corrosion rate. This is due to the combined effects of mass transfer, charge transfer, and wall shear stress. The pitting corrosion was also discussed in view of the aspects above.

Keywords

• low alloy steel
• fluid simulation
• flow corrosion
• local corrosion pits
• weld reinforcement height
• electrochemical measurements