Study on mechanical properties of high-strength steel butt-welded joints

In this research, using the notched tensile specimens, the material properties of hardened heat-affected zone (HHAZ), softened heat-affected zone (SHAZ), welding material zone (WM), and base metal zone (BM) in the butt-welded joints made of Q550 and Q690 steels respectively and their strength-matching welding materials were first experimentally studied. The obtained material properties of each zone in the steel butt-welded joints were used to numerically determine the strength of high-strength steel buttwelded joints and were further validated by the experiment results. According to this research, for a given heat input energy and geometry, the strength of SHAZ in high-strength steel butt-welded joint were deteriorated, compared with that of base metal. Due to the constraining effects from WM and HHAZ, the strength of the high-strength butt-welded joint was lower than that of the base metal but higher than that of SHAZ.)