Determination of fatigue behavior of welded armor steel madeof tempered martensitic steel

Armor steels utilized in military vehicles serve the critical purpose of safeguarding personnel. The welding process is one of the most important joining methods. Although the welding process provides many advantages in terms of joining technique, a decrease in strength in the welded area may be inevitable. This study aimed to ascertain the fatigue strength of welded samples composed of tempered martensitic steel. Cruciform welded samples with different penetrations were first subjected to non-destructive tests and then to destructive tests. Detailed measurements of weld penetration and weld toe radius were performed. A novel evaluation method was introduced for assessing weld penetration. Weld toe radius values were determined by the curvature method based on the point cloud data obtained using a three-dimensional scanner. Notably, among non-welded samples, those cut by the water jet method with anti-buckling restraints exhibited the highest fatigue resistance. It was observed that as welding parameters increased, weld penetration also increased, leading to a decrease in fatigue strength. Welded sample number 1, with the lowest weld penetration, demonstrated the highest fatigue strength.