Although the characteristics of the grinding fluid are still unclear, it should be recognized that under the combined effect of the above-mentioned various characteristics, its effect can be enhanced. In the course of use, it is not advisable to consider only a certain characteristic. The main feature of oil-based grinding fluid is lubricity, while the main feature of water-based grinding fluid is cooling. Due to its lubricating properties, oil-based grinding fluids can prevent abrasive cutting edges from abrasion and can maintain grinding for a long time. Therefore, it has excellent effects on the amount of workpiece removal, grinding wheel wear, grinding force, machined surface roughness, and surface state of the workpiece (burns, cracks, residual stress), etc. For water-based grinding fluids, although they are not as effective as oil-based grinding fluids in improving the grinding performance, in water-based grinding fluids, soluble grinding fluids with a certain degree of lubricity and superior penetrating cleaning effect are still Have relatively excellent performance. The reason is that the soluble grinding fluid has a certain degree of lubricity, which can prevent the abrasive grains from becoming dull to a certain extent. At the same time, the grinding fluid that penetrates into the pores of the grinding wheel or the cracks of the abrasive particles has a good effect in preventing the clogging of the grinding wheel.
1. The influence of grinding fluid on surface roughness Oil-based grinding fluids with better lubricating properties have better grinding effects, and the surface roughness of the machined surface is better than that of water-based grinding fluids. In the water-based grinding fluid, the effect of the emulsion and the solubility are roughly equivalent, and a smaller surface roughness can be obtained. It can be seen that as the grinding depth increases, the surface roughness deteriorates. 2. The influence of grinding fluid on the microhardness of the machined surface and the depth of the hardened layer When using WA46LV grinding wheel to grind T7A carbon steel, the effect of different grinding fluids on the surface microhardness and hardened layer depth of parts. The surface microhardness of the parts that are ground with different grinding fluids is not much different, but the depth of the hardened layer is quite different. The grinding fluid with the smallest hardening depth is the aqueous solution, the emulsion is the second, and the dry grinding is the deepest. . When grinding W18Cr4V high-speed steel with WA60KV grinding wheel, the effect of grinding fluid on the surface microhardness and hardened layer depth is different from that of normalized carbon tool steel. Due to the secondary quenching, the hardness increases about 2 μm from the machined surface. When dry grinding is used, due to the low cooling rate, annealing occurs on the surface layer, resulting in lower hardness. 3. The influence of grinding fluid on residual stress In the grinding process, the thermal stress generated by the grinding heat is the main part of the part to participate in the profit, so the surface temperature of the part is very important. The figure shows the influence of different grinding fluids on the surface temperature and participating stress of the parts. The oily grinding fluid with extreme pressure additives has the lowest surface temperature and lower residual surface stress. But the experiment when grinding bearing steel shows that not all grinding situations have the law shown in the figure. For grinding bearing steel (59HRC), when the grinding depth is ap=0.025μm, oil-based Grinding fluid can get a good grinding effect, and the surface is under pressure. Under the condition of large grinding depth ap=0.05μm, oily grinding fluid is not good, the reason is that the grinding heat is high at large grinding depth , The oil-based lubricating fluid has poor cooling performance, and the grinding surface not only has a high temperature, but also participates in the profitability mostly in a state of tensile stress. 4. The influence of grinding fluid on the ground surface The influence of different grinding fluids on the number of times the workpiece can be ground before burns when grinding bearing steel. When grinding with dry grinding, water and emulsion, the extreme depth of burns is different: dry grinding produces the lowest extreme grinding depth of burns, and when grinding with emulsion, the extreme grinding depth of burns is the largest, while water is in the middle . At the same time, it can be seen that the ultimate grinding depth during wet grinding is almost doubled. Under the three grinding conditions, the emulsion has the best grinding effect. Among the grinding fluids, the oil-based grinding fluid has the most grind times, and the dissolving fluid has the least grind times. At the same time, in the solution, the addition of extreme pressure additives is more beneficial than the unadded grinding fluid to reduce grinding burns. Among the grinding fluids, model grinding fluids containing extreme pressure additives such as sulfur showed the most superior effect. According to analysis, this is mainly due to the reaction of the chalcogenide extreme pressure additive and the workpiece material, forming an iron sulfide film with lower shear strength, thereby reducing the wear of the abrasive cutting edge tip and maintaining normal grinding. 5. The influence of grinding fluid on grinding cracks The tempering temperature has a significant influence on the grinding cracks. When the workpiece is tempered below 100℃, the limit grinding depth of the crack is about 0.005mm, and when the tempering temperature is 300℃, the limit grinding of the crack will occur. The depth is 0.035mm, so the heat treatment state of the workpiece before grinding has a vital influence on the grinding cracks. In comparison, the type of water-based grinding fluid has an insignificant effect on grinding cracks. According to reports, oil-based grinding fluids are effective in preventing grinding cracks. Influence of Grinding Fluid on Grinding Performance of Grinding Wheel 1. The influence of grinding fluid on the amount of workpiece removal, grinding wheel loss, and grinding ratio Oil-based grinding fluids are the most effective for the amount of workpiece removal, grinding wheel wear, and grinding ratio, while water and grinding fluids are less effective. When comparing water-based grinding fluids with each other, the effects can be ranked as soluble, emulsified, and dissolving fluids, among which the soluble effect is the most significant. 2. The influence of grinding fluid on grinding force The effect of different types of grinding fluids on the grinding force is that the oil-based grinding fluid with good lubrication performance has the smallest grinding force. Between water and grinding fluid, the solution and the lubricating fluid are roughly equivalent, and the lubricating performance is poor. The grinding force of the dissolving liquid is large.
