Effect of Aluminum on Microstructure and Properties of Martensitic Wear-Resistant and Heat-Resistant Steel

The effect of aluminum on microstructure and properties of martensitic wear-resistant and heat-resistant steels was investigated. The results indicate that as-cast microstructure of the specimens is composed of ferrite, pearlite and carbides. After quenching at 1,000 °C and tempering at 600 °C, the microstructure of the specimens consists of tempered sorbite and Fe–Cr–Al intermetallic compounds which distribute directionally in the matrix and increase with increase in Al content. The additions of Al enhance the ambient tensile strength which reaches the peak at 1,230 MPa when the specimens contain 1.97 % Al. Oxidation notably decreases with the increase of Al and the average oxidation rates reduce to 0.0095 g m−2 h−1 at 650 °C and 0.0285 g m−2 h−1 at 800 °C, respectively. Wear resistance of the specimens containing Al obviously increased when compared to the Al-free specimens.