Surface Modification Studying Of Gear By High Current Pulses Electron Beam

Gear is a basic component in the mechanical equipment. The force of the gear is quite complex as it works, a variety of failure modes are induced, which requires the gear with high strength, high wear resistance and corrosion resistance, etc. With the rapid development in the field of aviation, aerospace and automobile, especially in recent years, the requirement of the gear tends to be large transmission ratio, high efficiency, low noise, light weight, small size, etc. Improving the surface property of a gear and prolonging its service life has become the vital things in public concern.To prolong a gear's life span, besides optimizing the transmission structure, the basic way is to increase the manufacturing precision and surface finishing degree. The main failure mode is dedendum rupture caused by the surface fatigue crack. There is a large relation between the micro crack and the surface roughness. If the strength and toughness is high enough in the core part of a gear and the surface property is good, the life span will be largely prolonged. With the rapid development of gear surface treatment technology, mass of surface modification techniques have been widely adopted. Including carburizing, nitriding, carbonitriding, surface alloying, laser surface hardening, thermal spraying and surface treatment compound technologies.High-current pulsed electron beams (HCPEB) is a new kind of surface modification technique, which possesses high efficient and high energy density.The surface structure, properties of surface layer of samples can be improved directly and effectively. This article arises a content of the project of National Natural Science Foundation of China,"the study on process and property of surface amorphized gears"(No.50775229). The optimizing process was studied through the treatment of gear material by using HCPEB, in order to obtain the gears with high strength and ductility, improved wear and corrosion resistance and longer life span. The main works of the thesis are as follow: (1) The numerical simulation of the temperature field in the process of material surface modification by HCPEB. The finite element analysis (FFA) software ANSYS was applied to simulate the process of modification and obtained the temperature distribution, the start time of melting, the thickness of the melted layer and the range of the heat-affected zone. (2) The analysis of surface structure and properties of gear material after the treat by HCPEB. Some surface properties, such as surface morphology, microhardness, roughness and corrosion resistance of the surface before and after irradiation was comparative analyzed, and a group of optimized parameters of machining process using pulsed electron beams was given. (3) Surface modification of the gears by electron beams. In order to achieve the goal, a special fixture for gear was designed. Including fatigue strength, some properties of the gears after surface modification by HCPEB were investigated.In this paper, a new method of surface modification of gear was proposed. The properties of the surface on the gear are improved through pulsed electron beams treat. This study provides a theoretical basis and experimental data for high performance gear.