Characterization of Armour Steel Welds Using Austenitic and Ferritic Filler Metals

In this study, fillet welding processes were performed on high strength Miilux Protection 500 (MIL-A-46100) steel, which is used as armour material in defence industry, using GMAW method with austenitic ER307 and ferritic ER110S-G filler metals. The characterization of welded structure was carried out by performing elemental mapping processes as well as microstructural examination and microhardness tests. Results showed that hardness of weld metal was found to be 46% and 78% of the base metal hardness for austenic and ferritic filler metal, respectively. The fine-grained heat-affected zone was found to be the highest hardness while intercrital heat-affected zone was found to be lowest hardness through heat-affected zone. The smoother decrease was obtained in the softening zone with austenitic filler metal due to lower thermal conductivity. Consequently, the hardness values at a distance of 6 mm from the plate edge for both filler metals reached the hardness of base metal and both welded structures met the minimum requirements of the military standards.