齿轮钢表面激光毛化工艺对微织构 ① 成形质量的影响

Existing research on microtextures predominantly concentrates on their wear-reducing effects on working surfaces and the associated influencing factors. However, comprehensively understanding of microtexture wear-reduction mechanisms remains elusive. Moreover, the effects of heat input and arrangement spacing on the formation quality of microtextures remains relatively shallow. This knowledge gaps hinder effective implementation of microtextures for wear reduction in practical applications, highlighting the need for further research. This study addresses the issue of excessive wear in the side-by-side gear assemblies of vehicle power systems. A novel wear-reduction strategy was developed that involves the use of laser technology to create microtextures on the end faces of a 38CrSi gear steel to enhance the load-carrying capacity of the lubricating oil, and thus mitigate gear wear. Initially, a mathematical lubrication model was constructed based on the Reynolds equation. This model analyzes the influence of the microtexture arrangement spacing on the pressure distribution of the lubricating oil film. Through meticulous calculations of the oil-film pressure distribution under various arrangement spacings, a significant finding emerged: reducing the microtexture arrangement spacing can effectively improve the load-carrying capacity of the oil film. Specifically, when designing wide-spaced microtextures, the optimal spacing should be below 0.30 mm, and for narrow-spaced ones, it should not exceed 0.15 mm. This discovery provides crucial theoretical guidance for optimizing the layout of microtextures. Subsequently, a series of process experiments were conducted by varying the microtexture arrangement spacing and scanning speed. The experimental results revealed that when the arrangement spacing was narrow, a large heat input caused mutual thermal interference owing to the overlap of the heat-affected zones. This interference disrupts the stability of the microtexture-forming process and prevents the formation of high-quality microtextures. However, a small heat input fails to meet the requirements for the depth and size of the microtextures, which are essential for their proper functioning. Laser scanning speed is crucial in microtexture preparation. A lower scanning speed led to significant remelting and backfilling of the metal deposition layer. This phenomenon affects the depth and shape of the microtextures, resulting in an irregular and less effective structure. Conversely, a higher scanning speed may cause insufficient heat input, leading to poor forming quality, such as incomplete microtexture formation or weak bonding with the substrate. Finally, an optimized microtexture preparation process is proposed. After thorough experimentation and analysis, the optimal laser texturing process parameters were determined. These parameters included a laser power of 160 W, a scanning speed of 10 mm/s, a pulse frequency of 95 kHz, 10 processing cycles, and an arrangement spacing of 0.3 mm. This optimized process effectively enhanced the lubrication performance of the surface of the gear steel, significantly reducing wear. It also demonstrates good adaptability in industrial applications and offers a practical solution for improving the durability of mechanical components. Additionally, this study provides a valuable reference for preparing microtextures on similar metal surfaces. This promotes the broader application and development of microtexture technology in diverse industries such as machinery manufacturing, where reducing friction and wear is crucial for improving the efficiency and lifespan of equipment, and aerospace, where component reliability under extreme conditions is crucial.