Abstract
Quenched and tempered (Q&T) steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking in the heat affected zone (HAZ) after welding and HAZ softening. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only remedy because of higher solubility for hydrogen in austenitic phase. Recent studies proved that high nickel steel (HNS) and low hydrogen ferritic (LHF) steel consumables can be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the effect of welding consumables on tensile and impact properties of high strength, Q&T steel joints. Three different consumables, namely ASS, LHF steel and HNS have been used to fabricate the joints by shielded metal arc welding (SMAW) process. The joints fabricated using LHF steel electrodes showed superior transverse tensile properties than other joints. The joints fabricated using HNS electrodes exhibited better impact properties than other joints. The joints fabricated by LHF steel electrodes exhibited lesser degree of HAZ softening, while HNS joints exhibited the maximum HAZ softening due to the difference in weld thermal cycle.
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