Bending strength of rolled H section steel welds jointed by newly developed flash welding system

Abstract

For joining large sectional members, such as I section or H section steels, on site, a flash welding system was newly developed. When H section steel (600 x 300 (mm)) was joined by using the newly developed flash welding system, the joining time was 1/10 compared with conventional arc welding. There is also an advantage that when this system is used, members are employed directly from gas cutting without groove preparation. If flash welding is performed, weld reinforcements (called reinforcements hereinafter) are inevitably generated at the joints. Reinforcements are generally removed because they become the source of stress concentration and they may possibly have a bad influence on the mechanical properties of the joints. Therefore, bending tests were carried out on small specimens cut from the flanges of H section steels and on the welded member itself to evaluate bending strength of the joints as the structural members. No cracks occurred in the welds of the small specimens in bending test at - 40 C, - 20 C and at room temperature. Therefore, it was concluded that the un-welded zone on the upset metal did not lower the bending strength of the joints. The welded members had sufficient bending strength without fracture in the full plastic moment.