Tensile and fatigue properties of large structural members by a newly developed welding system

Abstract

In the civil engineering and architecture fields, welding of large sectional members, such as I section and H section steels, are usually required. A flash welding system, by which large I section steel or H section steel can be welded for a short time, was newly developed to shorten the joining time of large sectional members. The joining time of rolled SS400 H section steel (300 x 300 x 10 x 12 ((mm)) was about 5 min (Joining time was 1/10 compared with that of arc welding). From the results of tensile tests, the joint efficiency of welded joints by the newly developed flash welding system was 100 percent for the specimens with reinforcements and 93 percent without reinforcements. In fatigue tests, the fatigue strength of welded joints with reinforcements was about 50 percent of that of the base metal. By removing the reinforcement naturally generated by flash welding, the fatigue strength of flash welded joints became 75 percent of that of the base metal. In fatigue design, flash welded joints with reinforcement had the same grade of fatigue strength as the non-load-carrying fillet joints by arc welding.