Microstructural Understanding of Flow Accelerated Corrosion of SA106B Carbon Steel in High-Temperature Water with Different Flow Velocities

Abstract

All light or heavy water reactors fabricated with carbon steels suffer from flow-accelerated corrosion (FAC). The FAC degradation of SA106B with different flow velocities was investigated in terms of microstructure. As flow velocity increased, the major corrosion type changed from general corrosion to localized corrosion. Severe localized corrosion occurred in the pearlite zone, which can be the prior location for generating pits. After normalizing, the improvement in microstructure homogeneity reduced the oxidation kinetics and lowered cracking sensitivity, causing a decrease in FAC rates of 33.28%, 22.47%, 22.15%, and 17.53% at flow velocity of 0 m/s, 1.63 m/s, 2.99 m/s, and 4.34 m/s, respectively. Additionally, localized corrosion tendency was decreased by reducing the micro-galvanic effect and tensile stresses in oxide film. The maximum localized corrosion rate decreased by 21.7%, 13.5%, 13.8%, and 25.4% at flow velocity of 0 m/s, 1.63 m/s, 2.99 m/s, and 4.34 m/s, respectively.

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

“…Among the factors mentioned above, the flow velocity is the predominant factor influencing the corrosion of the steel [13][14][15][16][17]. Moreover, it is usually referred to as flowaccelerated corrosion (FAC) [18,19]. Various studies have been conducted in the past decades to understand the mechanism of the FAC of steel [20][21][22][23].…”

Particle Properties of Air Nanobubbles and Their Inhibition Mechanism on Brass Corrosion in Recirculating Cooling Water: Effects of Concentration Ratio and Flow Velocity

“…Additionally, an increase in flow velocity accelerated the erosion‐corrosion process on metal surfaces. [ 22 ] Therefore, the changes in particle properties of A‐NBs and corrosion conditions under different flow velocities are significant factors to be considered in the development of the A‐NBs corrosion inhibition technique.…”

Flow-Assisted Corrosion of Carbon Steel in Simulated Nuclear Plant Steam Generator Conditions

“…The dissolution rate is, in fact, equal to the sum of the current densities of the dissolution of the oxide and transfer of iron ions from the metal through the oxide layer, which emphasizes its role as one of the controlling factors of FAC [10,11]. Several works [13][14][15][16][17] have been devoted to the characterization of the thin iron oxide layers formed on the carbon steel components under the chemical and hydrodynamical conditions prevailing within the secondary circuit of PWR plants (de-aerated and alkaline turbulent water or wet steam). However, the mechanism of the process has not been studied in detail with electrochemical methods.…”