TIG-dressing of High Strength Steel Butt Welded Connections – Part 1: Weld Toe Geometry and Local Hardness☆

This paper presents the results of extensive measurements on weld toe geometry of as-welded and TIG-dressed butt welded connections in high strength steels S460, S690 and very high strength steels S890 and S1100. Descriptions of the measurement techniques and data analysis are presented. Four weld toe parameters have been formulated to characterize the weld toe: weld toe radius, weld toe angle, weld height and undercut. From the data can be concluded that TIG-dressing, on average, has a beneficial effect on the geometry of the weld toe. However, TIG-dressed weld toes have different appearances and as a result, weld toe parameters show more variation after TIG-dressing. An improvement of the weakest link is therefore not guaranteed. The reheating of weld material and surrounding parent material results in a new fusion zone (FZ) and heat affected zone (HAZ). Hardness measurements have been performed in all different zones and show an increase of hardness as a result of TIG-dressing, with an occasional exception in the very high strength steels.