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.

Effect of Surface Roughness on the Corrosion of HP-13Cr Stainless Steel in the Dynamic Aggressive Oilfield Environment

“…Various studies have been conducted in the past decades to understand the mechanism of the FAC of steel [20][21][22][23]. Initially, it was found that a higher flow velocity could enhance the mass transfer process at the interface, thereby accelerating the corrosion [24][25][26]. More recent studies have shown that, in addition to the flow velocity, different fluid regimes, such as bubbly flow, plug flow, stratified flow, wavy flow, and slug flow, play an important role in determining the FAC behavior [27,28].…”