低温纳米流体的润滑性能和磨削加工性能试验研究

发布时间：2018-04-01 17:10

本文选题：低温冷风纳米粒子射流微量润滑　切入点：低温纳米流体　出处：《湘潭大学》2017年硕士论文

【摘要】：磨削加工能获得较好的表面精度,提高表面质量,是不可或缺的精加工工艺。但由于砂轮表面磨粒与工件接触时,通常是负前角切削,因此磨削加工中的磨削温度和磨削力都大于其他加工形式。面对磨削加工中的磨削热和磨削力,现在广泛的应用浇注式润滑冷却方式,但是由于浇注式润滑冷却方式,在高速高载加工中的冷却润滑性能并不突出,且磨削液的大量使用会造成环境的污染和加工成本的提高,所以提出了绿色磨削加工方式。干磨削和低温冷风微量润滑技术虽然可以满足环保的要求,但是其润滑冷却效果不理想,难以获得较好的工件表面质量。提出了低温冷风纳米粒子射流微量润滑技术,综合了低温冷风和纳米粒子射流润滑技术的优点,通过在低温磨削液中添加纳米颗粒,不仅提高了磨削液的换热性能,降低磨削区的磨削温度,同时由于纳米颗粒的自身物理特性和磨削温度的下降,进一步增强了磨削液的润滑性能。本文的主要工作包括如下几个方面:1、运用了“二步法”,将纳米二硫化钼颗粒添加到植物性的低温磨削液中,制备了不同质量分数的低温纳米流体,通过静置一段时间后,测量流体顶部的渐变层高度来评估不同纳米粒子质量分数下的低温纳米流体的悬浮稳定性。2、对制备的8中不同质量分数的低温纳米流体进行了基于淬硬轴承钢GCr15材料的湿式往复摩擦磨损实验,通过测量摩擦磨损过程中的摩擦系数,磨损后的沟槽形貌和对磨钢球的磨斑大小来表征不同质量分数的低温纳米流体的润滑性能,得出了其中润滑性能最优的一个质量分数。3、基于干磨削、浇注式磨削、低温冷风微量润滑磨削和低温冷风纳米粒子射流微量润滑磨削四种不同的磨削工况对淬硬轴承钢材料进行了磨削加工实验,通过衡量不同磨削参数下的法向磨削力、比磨削能和磨削温度,来评估不同的润滑冷却方式在不同的磨削参数下的适应性,针对低温冷风纳米粒子射流微量润滑技术,得到一个较优的磨削参数。摩擦磨损实验结果表明,低温纳米流体能有效的降低摩擦系数,减小工件和和钢球的磨损;对淬硬轴承钢的磨削试验结果来看,低温纳米粒子射流微量润滑技术可以有效的降低磨削过程中的磨削力和磨削温度,提高表面质量,尤其是在高速重载的条件下,其优越的冷却润滑性能更加突出。
[Abstract]:Grinding can obtain better surface precision and improve surface quality, which is an indispensable finishing process. However, when grinding wheel surface abrasive particles are in contact with workpiece, it is usually cutting at negative front angle. Therefore, the grinding temperature and force in grinding process are higher than other machining forms. Facing the grinding heat and force in grinding machining, it is widely used in pouring lubricating cooling mode, but because of pouring lubricating cooling mode, The cooling and lubricating performance in high speed and high load machining is not outstanding, and the extensive use of grinding fluid will cause environmental pollution and increase the processing cost. Therefore, the green grinding processing method is put forward. Although dry grinding and low temperature cold air micro lubrication technology can meet the requirements of environmental protection, its lubricating and cooling effect is not ideal. It is difficult to obtain good surface quality of workpiece. This paper puts forward the micro lubrication technology of low temperature cold air nanoparticle jet, which synthesizes the advantages of low temperature cold air and nano particle jet lubrication technology, by adding nanometer particles to the low temperature grinding fluid. It not only improves the heat transfer performance of the grinding fluid and reduces the grinding temperature in the grinding area, but also reduces the physical properties of the nanoparticles and the grinding temperature. The lubricity of grinding fluid is further enhanced. The main work of this paper includes the following aspects: 1. By using "two-step method", the nano-molybdenum disulfide particles are added to the low temperature grinding fluid of plant properties. Low temperature nanofluids with different mass fractions were prepared. The gradient layer height at the top of the fluid was measured to evaluate the suspension stability of low-temperature nano-fluids with different mass fraction of nano-particles. 8 low-temperature nano-fluids with different mass fractions were prepared based on hardened bearing steel GCr15. Wet reciprocating friction and Wear experiment of Materials, The lubrication properties of low temperature nanofluids with different mass fractions were characterized by measuring friction coefficient, groove morphology and wear spot size of steel ball during friction and wear. A mass fraction of which has the best lubricity. 3, which is based on dry grinding, pouring grinding, Four different grinding conditions, low temperature cold air micro lubrication grinding and low temperature cold air nano particle jet micro lubrication grinding, are carried out on grinding of hardened bearing steel material. The normal grinding force under different grinding parameters is measured. Specific grinding energy and grinding temperature are used to evaluate the adaptability of different lubricating cooling methods under different grinding parameters. A better grinding parameter is obtained. The results of friction and wear experiments show that the low temperature nano-fluid can effectively reduce the friction coefficient and the wear of workpiece and ball. Low-temperature nano-particle jet micro-lubrication technology can effectively reduce the grinding force and grinding temperature, improve the surface quality, especially under the condition of high speed and heavy load, its superior cooling lubrication performance is more outstanding.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG580.15

【参考文献】