Statistical analysis of residual stresses in austenitic pipe girth welds

Abstract

Residual stresses created from welding have a direct influence on fracture mechanisms of cracks and flaws in and around welded regions. Excessive residual stress can lead to unexpected failures and an important property in fitness-for-service calculations. In this work, an experimental database of the residual stress of low heat input austenitic girth welds is analysed for statistical correlation. The combined measurement profiles indicate normality throughout the weld thickness. Two-sample tests of grouped datasets were additionally carried out to examine potential relationships within the data. Presented measurements were characterised by location from weld centre, and similarly, by pipe aspect ratio. Results indicate a moderate influence of dimension ratio on residual stress in piping components suggesting potential for additional consideration in fitness-for-service procedures.

The Different Welding Layers and Heat Source Energy on Residual Stresses in Swing Arc Narrow Gap MAG Welding

“…These large enough mismatch strains lead to plastic deformation of the part, which greatly affects residual stress during processing [4,5]. In addition, during hightemperature melting and cooling solidification, the intermediate zone is constrained by the surrounding environment, generating tremendous tensile residual stresses altering the mechanical properties of the workpiece connection, and the structure is deformed, cracked, creep damage and other adverse effects, affecting the working life of the workpiece [6][7][8][9][10]. Therefore, the inevitable welding residual stress plays an essential role in the connection and pressure bearing of the equipment; effective control and study of the residual stress distribution can ensure the integrity of the pressure equipment…”