The Effect of Welding Residual Stress for Making Artificial Stress Corrosion Crack in the STS 304 Pipe

Abstract

The stress corrosion crack is one of the fracture phenomena for the major structure components in nuclear power plant. During the operation of a power plant, stress corrosion cracks are initiated and grown especially in dissimilar weldment of primary loop components. In particular, stress corrosion crack usually occurs when the following three factors exist at the same time: susceptible material, corrosive environment, and tensile stress (residual stress included). Thus, residual stress becomes a critical factor for stress corrosion crack when it is difficult to improve the material corrosivity of the components and their environment under operating conditions. In this study, stress corrosion cracks were artificially produced on STS 304 pipe itself by control of welding residual stress. We used the instrumented indentation technique and 3D FEM analysis (using ANSYS 12) to evaluate the residual stress values in the GTAW area. We used the custom-made device for fabricating the stress corrosion crack in the inner STS 304 pipe wall. As the result of both FEM analysis and experiment, the stress corrosion crack was quickly generated and could be reproduced, and it could be controlled by welding residual stress.

Stress Corrosion Cracking Threshold for Dissimilar Capacitive Discharge Welding Joint with Varied Surface Geometry

“…It is found that the high hydrostatic pressure, low hydrogen, and temperature trigger localized corrosion induced SCC [4,5]. Various efforts have been conducted to understand and mitigate the SCC in stainless steels and their welding joints; however, these studies mostly focus on the welding joints of similar metals while the real challenge in dissimilar metal welds is still overlooked [6][7][8]. Dissimilar welding promotes a strenuous task due to the melting point difference [9].…”

Characterization of Crack Tip Mechanical Field of Inhomogeneous Materials in Welded Joints by USDFLD Subroutine

“…Besides, the fusion line is located between the weld zone and the heat-affected zone, and the heterogeneity of material microstructure and mechanical properties is significant. ere is a high probability of brittle fracture and initiation of welding cracks in the area around the fusion line, which is usually the weak link of welded joints [26,27]. For example, Figure 1(b) shows the fracture of the cutting pick base of the coal mine tunnel boring machine.…”

Optimum power for ER-70S-2 and SS400 dissimilar CDW joint

“…Thus, two of the SCC's three components already exist in the weld joints, and when the weld joints are exposed to a corrosive environment, SCC can occur. The SCC behavior of fusion welding has been investigated using both experimental and numerical approaches via quantitative and qualitative methods [11][12][13][14][15][16][17]. Kim et al [11] studied the effect of residual stress on the SCC growth in GTAW joints.…”