Load‐carrying capacity of MAG butt and fillet welded joints on high‐strength structural steels of grade S960QL and S960MC

Abstract

The use of high-strength structural steels brings great advantages in constructions regarding material requirements, weight reduction and productivity. Different steel grades within the S960 range are commercially available but not yet represented in Eurocode 3. The weldability of these steels is limited to smaller process windows to ensure the high material properties. In contrast to steels with moderate strength, there is a considerable risk of softening in the heat-affected zone causing a strength reduction of the connection. By now, the current EN 1993-1-12 only extends the design rules to cover steel grades up to S700. Therefore, the potential of these high-strength steels cannot be used to its full extent in structural engineering. This study, made within a steel application research project (FOSTA P 1507), deals with the weldability and load-carrying capacity of butt and fillet welded joints of S960QL and S960MC produced by gas-shielded metal arc welding. The influence of different bevel geometry, filler metal, and plate thicknesses was investigated. To extend the design rules up to S960, a need of an amendment was found for some combinations.