By the end of June 2019, the total number of motor vehicles in China had reached 357 million. With the increasing number of automobile consumers, the quality problem of automobile products has become more and more prominent. Auto parts are a very important part of the automobile system. Due to the characteristics of the automobile system, the quality of auto parts directly affects the safety of automobile driving. Therefore, the product quality of auto parts has become an important factor for consumers to refer to when buying a car.
1) For the machining process of raw materials, we must consider drilling first and then carburizing. In this way, the residual compressive stress is generated on the inner surface of the piston pin through quenching, which greatly improves the fatigue life of the piston pin.
2) By shortening the carburizing time, prolonging the diffusion time and reducing the carbon concentration on the surface of parts, the depth of massive carbide can be effectively controlled and the stress concentration and embrittlement of carburized layer can be reduced.
The automobile piston pin is an important part connecting the automobile piston and connecting rod. In the process of use, it is equivalent to a two-point support beam and bears asymmetric alternating load. Its surface works under friction conditions for a long time. The main form of piston pin damage is surface wear, but sometimes there are fracture and cracking. According to the damage form of piston pin, reasonable heat treatment process can be adopted to reduce the damage of piston pin in use, so as to improve the quality and service life of piston pin.