Austenitic Stainless Steel and Martensitic Transformation in Welded High-Hardness Armor Steel

Abstract

An austenitic filler material is traditionally used for welding armor steels, thus avoiding the negative effect of hydrogen content due to slow diffusion towards the sensitive fusion line. For heavy structural engineering such as armored military vehicles, which are frequently affected by impact and dynamic load, it is crucial to know the dynamic properties of the most sensitive area of welded joints, the weld metal zone. Due to a significant interest in quantifying material resistance to crack initiation and propagation, the fatigue crack growth rate was measured in the welded metal zone, while the resistance to crack growth in the weld metal was tested by the amount of austenite transformed into martensite. Accordingly, the threshold stress concentration factor was 10 MPa m1/2. XRD spectral analysis revealed a direct transformation of γ – austenite into α’ – martensite.