Abstract: Influence of destabilization heat treatment on hardness, microstructure and erosion resistance of 27 wt.% Cr irons have been investigated. The specimens were heattreated by destabilization at 950 and 1100°C for 3 h and then air cooled followed by tempering in 400°C for 1 h then air cooling. The microstructure was analyzed by X-ray diffraction, scanning electron microscopy andlight microscopy. The results show that the microstructure in 27 wt.% Cr after destabilization and tempering, consists of secondary carbides in a tempered martensitic matrix. It was found that erosion resistance of the irons was improved after destabilization and tempering heat treatment at 1100°C more than at 950°C destabilizing temperature.