Welding residual stresses in thick steel plates—MAG-welded at low ambient temperature

Abstract

In this work, some results from experimental and numerical investigations on construction site welds under low ambient temperatures down to −10 °C are shown. These temperatures have been simulated inside a climatic chamber. The aim of these investigations is to show the influence of low ambient temperature on resulting welding-induced residual stresses. Residual stresses may vary depending on different ambient temperatures resulting in different cooling rates. Higher cooling rates are known to influence phase transformations, hardness distributions, and eventually residual stresses. To represent site conditions as close as possible to reality, large-scale components have been investigated. Wall thicknesses of the investigated specimens have been up to 30 mm. The specimens of general fine-grained construction steel have been metal active gas (MAG)-welded. The main focus of this work has been on welding residual stresses. These residual stresses have been measured using X-ray diffraction. In addition to the experimental work, numerical welding simulations have been carried out. The calculated and experimentally obtained data have been compared. The obtained results do not show significant influence of ambient temperature regarding welding residual stresses when welding is done in accordance with technical standards. Especially when preheating and inter-pass, temperatures are monitored and meet the standards.