Evaluation of the physical and mechanical properties in the surfacing zones of L53 and quenched-and-tempered 65G steels

Abstract

This paper presents an experimental evaluation of the mechanical properties in the surfacing zones of hot-rolled L53 steel and quenched-and-tempered 65G steel. Hardness was measured across the surfacing bead, the near-weld zone (NWZ), the heat-affected zone (HAZ), and the base metal. The results show that thermal exposure during surfacing produces a pronounced heterogeneity of mechanical properties, most notably in the NWZ. For both steels, the hardness in the NWZ increases by up to 7 HRC relative to the initial value. In L53 steel, the HAZ segment (about 5.5 mm in length) that follows the NWZ exhibits only a minor hardness increase of up to 2 HRC, whereas the hardness in the corresponding HAZ segment (about 6.5 mm in length) of 65G steel decreases by up to 6.5 HRC relative to the initial value. The greatest scatter of hardness values is observed in the NWZ, where heat strongly affects the local mechanical properties. Overall, the hardness distributions in pre-hardened 65G steel are broadly similar to those in L53 steel, but with more pronounced changes in the HAZ. These findings should be taken into account when optimizing repair and hardfacing technologies for soil-engaging parts of tillage equipment.