Ultimate limit load in welded joints and in net sections of high strength steels with yield stress 960 MPa

摘要

Ultra-high strength steels are becoming more common, particularly in lifting machinery and mobile equipment. However, elongation is a problem in ultra-high strength steels, which has been reported to be low in traditional material tests. Although in these tests, ultra-high strength steels have exhibited good local strain properties, which suggests that traditional material test procedures are inappropriate. In this paper, notched specimens were used to develop material models and to define failure criteria. The results were verified using welded components and tensile tests. The failure point and capacity levels were determined in welded and net section tests. We conclude that the strain properties of ultra-high strength steels are good, where the full capacity of the net section stress was reached in the tensile tests. The results also indicate that the current elongation requirements in different codes require adjustments or a new formulation.