The effect of heat treatment on the abrasive and erosive wear behaviour of laser metal deposited Fe–28Cr–2.7C alloy

The abrasive wear behaviour of laser metal deposited Fe–28Cr-2.7C alloy with subsequent heat treatments has been investigated. Two heat treatments were applied: (HT1) 1200 °C for 4 h then air cooled to room temperature, followed by 960 °C for 4 h then air cooled, and (HT2) 960 °C for 4 h then air cooled. The abrasive wear resistance of the HT1 condition was significantly higher than that of the HT2 condition. However, the performance of both was inferior to their cast counterpart, despite having similar alloy composition, phases (eutectic M7C3, martensite, and secondary carbide precipitates), and hardness (719–738 HV). HT1 and HT2 samples consisted of a refined carbide structure due to the increase in nucleation and suppression of carbide growth because of the fast solidification rates during the laser deposition process. It was found that the volume loss increased with decreasing carbide size and mean free path between the M7C3 carbides. This was due to the sub-micron globular shaped carbides produced by the laser deposition process being easily fractured or scooped off during plastic deformation caused by the abrasives.