Abstract: In this paper,the high temperature friction and wear characteristics of 23-8N valve steel after full aging and solid solution aging are investigated,and the microstructure and phase composition of the valve steel are also analyzed.The results show that (1) the friction coefficients and wear loss of two different heat treatment specimens both tend to decrease first and then increase with the rising of temperature; (2) at the room temperature,the full aging specimen has better anti-wear performance,and the surfaces of the two different heat treatment specimens are distributed with grooves and adhesive traces,indicating that the prevailed wear mechanism is abrasive wear and ad- hesive wear; (3) at a high temperature,the solution and aging specimen has better wear resistance due to its thic- ker oxide film; (4) at 400℃,the two specimens are covered with dense oxide films,so the wear loss of the speci- mens is the lowest and the main wear mechanism is mild oxidation wear; and (5) as the temperature rises from 500℃ to 650℃,the wear loss gradually increases,and the predominant wear mechanism transforms from mild oxi- dation wear into severe abrasive wear,adhesive wear and the fatigue delamination of oxide films.

Key words: heat treatment, 23-8N engine valve steel, high temperature friction and wear, wear mechanisms