Development of Structural Steel With Superior Resistance Against Fatigue Crack Growth

Abstract

The fatigue crack problems that broke out at the end of the twentieth century were fatigue crack properties in hull structures. This motivated research on a lot of technologies against fatigue fracture. It was clarified that the detection of fatigue crack initiation in complex welded structures like hulls is quite difficult, and that the crack length at recognition is mostly long compared to mechanical parts. From these research results, not only stress reduction at critical areas by improvement in design but also newly developed materials with excellent resistance to fatigue crack growth has been desirable for structural integrity. The newly developed structural steel, in which fatigue crack growth resistance is controlled by microstructures, will be introduced in this report. Various fatigue properties of the base steel plates in air and in synthetic sea water are compared. And the fatigue life extension effects by FCA is observed in fatigue tests of welded joints and welded structural models.

Parametric analysis of the stringer bead reinforcement area and prediction of the number of beads in a single-V butt joint, using the robotic Flux-cored arc welding technique

“…Nevertheless, Q limitations are usually set depending on the material to be welded such as in the case of steels produced by thermomechanical control process technologies (TMCP) which are usually welded with low heat input levels [17,18].…”