INFLUENCE OF THE MODE OF THERMAL TREATMENT AND LOAD RATIO ON THE CYCLIC CRACK-GROWTH RESISTANCE OF WHEEL STEELS

摘要

We study the microstructure, mechanical properties, and micromechanism of fatigue fracture of high-strength railway-wheel steel (0.63 percent C and 0.1 percent V). The necessity of elevation of the cy-clic fracture toughness of this type of steel by isothermal hardening and tempering at 500 deg C is substantiated. It is shown that the cyclic crack-growth resistance of steel decreases for high load-ing amplitudes as the load ratio (simulating the influence of residual thermomechanical stresses) increases.