Weldability and Impact Energy Properties of High-Hardness Armor Steel

In this study, the weldability of high-hardness armor steel by the gas metal arc welding method has been investigated. The study was aimed at determining the weakness points of manual welding compared to automated welding through microhardness testing, the cooling rate, tensile characteristics and nondestructive analysis. Detailed studies were performed for automated welding on the impact energy and microhardness in the fusion line, as the most sensitive zone of the armor steel weld joint. It was demonstrated that the selection of the preheating and interpass temperature is important in terms of the cooling rate and quantity of diffusible and retained hydrogen in the weld joint. The tensile strength was higher than 800 MPa. The width of the heat-affected zone did not exceed 15.9 mm, measured from the weld centerline, while the impact energy results were 74 and 39 J at 20 and – 40 °C, respectively.