Study on the effect of rotational speed on the polygonisation formation mechanism, microstructure and property evolution of D2 wheel steel

The D2 wheel steel rolling wear experiment was carried out on a double-disc wear test machine. By observing the polygonisation wear of the sample surface, measuring the vibration frequency, and analyzing sample microstructure and properties, the effects of rotational speed on the polygonisation formation mechanism, microstructure and property evolution of a D2 wheel steel were studied within a certain speed range. The results indicated that polygonisation wear was the result of the coupling of vibration and wear. The dominant vibration frequency (f) was constant at the three rotational speeds studied, and was equal to the product of the rotational speed (ω) and polygonisation order (K), that is, f=160Kω. When the number of rolling cycles was the same, the sample surface became subject to more times vibration and impact as the rotational speed decreased. This increased the intensity of the wear, and the polygonisation wear began to occur faster. Conversely, the polygonisation wear caused the vibration and impact load to increase, and the coupling effect of wear and vibration increased, further aggravating the polygonisation wear. After polygonisation wear occurred, the degree of crest oxidation wear was reduced in relation to the decreasing rotational speed. The degree of trough fatigue wear was also aggravated, causing the polygonisation wear gap to become larger, while the mass wearing quantity increased significantly given the same number of rolling cycles. The thickness of the obvious plastic deformation layer, the microstructure refinement, and the change in hardness of the surface layer all increased with the intensification of polygonisation wear. •F is constant at a certain speed range, and is equal to the product of ω and K.•The polygonisation wear appears faster as the rotational speed decreases.•The crest oxidative wear increases gradually, trough fatigue wear decreases.•The polygonisation gap become larger and the mass wearing quantity increases.•Microstructure refinement and hardness change of the surface layer all increase.