ABRASION WEAR RESISTANCE Of WELDED JOINTS BETWEENHARDOX STEEL 400 AND GRADE A SHIP STEEL

This paper presents the technological and microstructural aspects of the formation and heat treatment of awelded joint between two types of steel having significantly different chemical and mechanical properties, i.e.between low-alloy high-strength, abrasion wear resistant Hardox 400 steel and grade A marine constructionsteel. The test results indicate that connecting the two types of steel by welding leads to the formation of aheat-affected zone in the entire welded joint area with hardness levels reduced to approximately 170-180HV. This zone shows various microstructural changes which prevent a reliable evaluation of the abrasionwear resistance of the welded joint. Therefore, the article proposes an optimal technology of welding thetwo steel types, and welding technological parameters of the thermal post-treatment that allow the formationof microstructures having an increased–in comparison to the pre-welding condition–resistance to abrasionwear processes, as measured with the electro corundum #90 abrasive particles. Heat treatment optimized themicrostructure, improving the abrasion wear resistance by 16% compared to the as-welded condition.