Effect of welding defects on mechanical properties of welded joints subjected to temperature

Abstract

Welding defects negatively affect the safety of steel structures. In fire, the steel connections with welding defects would fracture prematurely that cause the structure lose their fire resistance. However, the knowledge of effects of welding defects on welding connections at elevated temperature are still limit. This paper conducted steady-state tensile tests on butt welded specimens with artificial defects to investigate the effect of defects on the mechanical properties of butt welding at high temperatures. These effects on the evolution law of stress and strain, fracture strengths and extension abilities were discussed. The results show that the stress concentration caused by the defects in the welding zone reduced the yield strengths of the weldments at high-temperature, and the stress concentration induced brittle fracture occurring at the welding zone at high temperature with low levels and produced different failure modes. The extension abilities of the weldments at different temperatures were influenced by the defect levels significantly.