Improvement In Fatigue Properties Of Welded Joints Using Crack Initiation Resistant Steel Part 1: Fatigue Strength Of Weld Heat Affected Zone And Cruciform Fillet Welded Joints

This study investigated whether the newly developed 490 MPa strength class steel, enhanced with solid solution elements, demonstrates superior fatigue properties in welded joints. The fatigue resistance of the Heat Affected Zone (HAZ) was assessed using simulated heat cycle tests. Subsequently, the evaluation was conducted using cruciform welded joints. The results showed that the fatigue strength of the developed steel exceeded that of conventional steel even within the HAZ microstructure. Additionally, it exhibited high fatigue strength in the welded joints as well. Overall, the developed steel offers superior fatigue strength in the HAZ, attributed to solid solution strengthening, and holds potential for improved fatigue properties in welded joints.