The effect of PWHT on the mechanical properties of HHA 500 armor steel welds

Armor steels are produced to protect against any explosions and armed attacks. In addition, high hardness armor (HHA) steels have excellent ballistic properties due to their hardness and strength. Choosing the correct welding method and providing optimum heat input when joining armor steels is very important in order to obtain the desired properties. Additionally, unwanted residual stresses occur after welding. It can be relieved by post-weld heat treatments (PWHT). This research aims to investigate the effect of PWHT on the mechanical properties and microstructure of Bisalloy HHA500 armor steel welded with gas metal arc welding (GMAW). The Bisalloy HHA500 series armor steels were joined with the automated GMAW method at optimized welding parameters through preliminary experimental tests. After welding processes, PWHT was applied at 650°C for 1 hour. In order to determine the mechanical properties of both as-welded and PWHT joints, tensile, bending, and Charpy-notch impact tests were performed. The microstructure investigation and hardness measurements were carried out. As a result of PWHT, an increase in the Charpy-notch impact strength by 16% was detected.