On-Site Welding Research for High-Strength S690 Steel

High-strength S690 steel is becoming increasingly popular in Hong Kong because of its numerous advantages in terms of mechanical properties and cost-effectiveness. Compared to normal-strength steel, the welding parameters such as preheat temperature, inter-pass temperature, and heat input energy of high-strength S690 steel should be controlled more strictly; additional post-weld heat treatment should be carried out for hydrogen diffusion in some situations. These strict requirements pose challenges to welding operations at construction sites. In Hong Kong, all field connections of high-strength S690 steel components are made using bolted connections, and there are currently no precedents for welded connections on site. To verify the reliability of on-site welding and optimize the welding process to facilitate operation, on-site welding tests of high-strength S690 steel with various welding procedures were conducted. These welding tests were first performed on the steel plates, followed by tests on the H-section steel components, to examine the mechanical reliability of the welding connections under tension and compression. The effects of heat input energy, welding joints, post-weld heat treatment, and wind blocking measures on welding quality and welding efficiency were studied.