Microstructural Analysis on Ballistic Tested Armour Steel Joints Fabricated Using Low Hydrogen Ferritic Consumables for Capping Pass

Abstract

Post impact microstructural characteristics of 7.62 armour pearcing incendiary bullet was studied on AISI 4340 multilayerd welded joints. The potential application of AISI 4340 steel is found in the construction of combat vehicles using welding process. The welded joints are expected to offer better ballistic resistance like unwelded parent metals in combat vehicles. The traditionally used austenitic stainless steel welding consumables and the transformation effects of the welding process result in inferior ballistic performance of AISI 4340 steel welded joints. Published information revealed that a few attempts were made to successfully resist the bullets at multi layered weld metals by depositing a hard-facing interlayer between traditionally used austenitic stainless steel filler metals and a austenitic stainless steel buttering layer in between the parent metal and the hard – facing interlayer. This paper reports the pre-impact and post-impact microstructural characteristics of multi layered sandwiched joints made of a austenitic stainless steel root, a chromium carbide hard – facing middle layer and a low hydrogen ferritic capping front layer. The effect of the low hydrogen ferritic front layer on the ballistic performance after impact is studied in detail.