Residual stress testing of weld specimens

Abstract

Residual stress caused by welding is invisible to the eye and usually requires special tools and technique to detect their presence. The techniques are often destructive in nature and the experiment may be costly, or even very complicated to perform, especially with large scale specimens. This project is about exploring the possibility of detecting residual stress on weld specimen by the use of ultrasound methods. The specimen used in this testing is a mild carbon steel specimen fabricated by butt-welding two identical pieces of mild carbon steel plates together at its centre. Data are collected near the weld joint and distance away from it. The purpose is to determine, if ultrasound technique is able to identify residual stress and if it is possible to automate the testing process.