Weldability of High Hardness Armor Steel

Abstract

High hardness armor steel (HHA) is developed for construction of military vehicle. HHA steel is complicated to weld as a result of its higher carbon content. Temporary researches give us insufficient recommendation how to optimize welding technology to get weld joint without cracks and flaws. The favorable mechanical properties and compromise between toughness and hardness can be obtained with optimal technology, appropriate heat input and the cooling rate in the temperature range from 600° C to 200° C. Present research through the automation process, carefully selection consumable and controlling cooling rate in the temperature range from 600° C to 200° C gave the welded joint without cracks and pores. Welded joint without flaws has also encouraged tensile strength value. The width of the HAZ was within the range of accepted in the standard MIL-STAN-1185 (max. 15.9 mm from the centerline of the joint). The micro-hardness throw the base metal is between 378 and 521 HV.