Dynamic Fracture Toughness of Armour Grade Quenched and Tempered Steel Joints Fabricated Using Low Hydrogen Ferritic Fillers

The armour grade quenched and tempered steel joints fabricated using low hydrogen ferritic steel (LHF) filler exhibited superior joint efficiency owing to preferential ferrite microstructure in the welds and also they offered required resistance to HIC. However, the combat vehicles used in military operations will be required to operate under a wide range of road conditions ranging from first class to cross country. Structural components in combat vehicles are subjected to dynamic loading with high strain rates during operation. Stress loadings within the vehicle hull of these vehicles are expected to fluctuate considerably and structural cracking especially in welds during the service life of these vehicles can lead to catastrophic failures. Under these conditions, fracture behaviour of high strain rate sensitive structural steels can be better understood by dynamic fracture toughness (K1d). Hence, an attempt was made to study dynamic fracture toughness of the armour grade quenched and tempered steel and their welds fabricated using LHF consumables. The experimental results indicate that the K1d values of the joints fabricated by shielded metal arc welding (SMAW) are higher than those of the joints fabricated using flux cored arc welding (FCAW) process