Experimental Study on the Wear Properties of 42CrMo Steel with Different Microstructures and T15 Laser Cladding

The surface properties of transmission parts are dependent on the composition of the alloying elements and microstructures. The hardness and wear resistance can be partly improved by a heat treatment process. In a few high strength materials, the surface performance can be greatly enhanced by a laser cladding process. In this paper, three kinds of heat treatment and T15 laser cladding processes were applied to 42CrMo to obtain the working surfaces with different microstructures. Tribological performances were tested in wear test machine, and the surface microstructures were observed by SEM/EDS. The average friction coefficients were 0.517, 0.591, 0.531 and 1.057 for the normalized, quenched, quenched and tempered and laser cladding layer, respectively. At a load of 70 N, the average wear rate was 0.58 × 10−6 mm3 N−1 m−1 for T15 layer and 1.90 × 10−6 mm3·N−1·m−1 for the quenched sample. The wear rate of the quenched sample was more than 3 times that of the T15 cladding layer. The T15 cladding layer has the best wear resistance. Plastic smearing exists on the worn surface for normalized and tempered surface. Abrasive wear was observed for both the quenched sample and the T15 layer, and fatigue cracks and spalling were observed for the T15 layer.