生物润滑剂微量润滑磨削GH4169镍基合金性能实验评价

Experimental Evaluation of Minimum Quantity Lubrication of Biological Lubricant on Grinding Properties of GH4169 Nickel-base Alloy

目的改善蓖麻油的综合润滑性能,尝试与黏度较小、流动性好的其他植物油混合,探究混合植物油同纯蓖麻油磨削GH4169镍基合金时的润滑性能差异。方法先进行1︰1混合植物油的探索性实验,以比磨削能、比磨削力、表面粗糙度、磨削温度为筛选参数,对筛选出的3个较优组同纯蓖麻油做对比,得出最优组,从脂肪酸角度分析润滑性能改善原因,并测量油膜接触角,进行验证。由于脂肪酸种类及含量的差异造成了润滑性能的不同,通过调节最优组的不同体积配比,改变其油液的脂肪酸含量占比,对相同的评价参数做进一步实验探究,分析脂肪酸含量占比变化对润滑性能的影响程度,最后根据表面微观形貌进行验证性分析。结果探索性实验得到的3个较优组分别为棕榈油、大豆油、玉米油同蓖麻油的混合组,发现随着这3组的不饱和脂肪酸含量依次提高,微液滴的接触角逐步减小。蓖麻油/大豆油在3组中的磨削温度最低,为100.7℃;表面微观形貌最优;接触角最合适,为70°;不饱和脂肪酸含量占比(质量分数)最合适,为66.5%。经过不同体积配比,进一步发现,随着不饱和脂肪酸占比逐步增大,润滑性能的评价参数在整体趋势上均阶段性地先减小、后增大,但在相邻的每种配比之间,各参数并不随不饱和脂肪酸占比的逐步增大而出现明显规律性。结论油液中的脂肪酸种类、含量占比对润滑性能的改善起着不可或缺的作用。硬脂酸促进皂化反应,提高成膜能力,不饱和脂肪酸C=C双键结构能够降低油膜密度,提高油液流动性。蓖麻油同其他植物油混合后,均不同程度地提高了不饱和脂肪酸比例,提高了油膜流动性,因此合适的不饱和脂肪酸占比可以兼顾液滴成膜能力和流动性。通过调小不饱和脂肪酸含量占比的变化幅度,发现不饱和脂肪酸占比可以阶段性对润滑性能的改善程度进行调控,但对润滑性能的精确调控还受到其他多种因素的制约。

Castor oil has excellent film-forming ability,but due to its high viscosity and poor fluidity,which limits its application in the field of machining lubrication.In order to improve the comprehensive lubrication performance of castor oil,try to mix it with other vegetable oils with low viscosity and good fluidity,and explore the difference of lubrication performance between mixed vegetable oil and pure castor oil in grinding GH4169 nickel-base alloy.First,the exploratory experiment of 1︰1 mixed vegetable oil was carried out.Taking the specific grinding energy,specific grinding force,surface roughness and grinding temperature as the screening parameters,the three optimized groups are compared with pure castor oil to obtain the optimal group.The reasons for the improvement of lubricating performance are analyzed from the perspective of fatty acid,and the oil film contact angle was measured for verification;Due to the difference of fatty acid type and content,the lubrication performance is different.By adjusting the different volume ratio of the optimal group,change the fatty acid content proportion of the oil,make further experimental exploration on the same evaluation parameters,analyze the impact of the change of fatty acid content proportion on the lubrication performance,and finally carry out confirmatory analysis according to the surface micro morphology.The three optimal groups obtained from the exploratory experiment are the mixed group of palm oil,soybean oil,corn oil and castor oil.It is found that the contact angle of micro droplets gradually decreased with the increase of the content of unsaturated fatty acids in the three groups.The grinding temperature of castor oil/soybean oil was the lowest in the three groups,which is 100.7 ℃;The surface micro morphology is the best;The most suitable contact angle is 70°;The proportion of unsaturated fatty acids is the most appropriate,66.5%.After different volume ratios,it is further found that with the gradual increase of the proportion of unsaturated fatty acids,the evaluation parameters of lubrication performance decrease first and then increase in the overall trend,but between each adjacent ratio,the parameters do not show obvious regularity with the gradual increase of the proportion of unsaturated fatty acids.The type,content and proportion of fatty acids in oil play an indispensable role in improving lubrication performance.Saponification reaction and improve film-forming ability can be promoted by stearic acid.Unsaturated fatty acid C=C double bond structure can reduce oil film density and improve oil fluidity.After mixing castor oil with other vegetable oils,the proportion of unsaturated fatty acids and oil film fluidity are increased in varying degrees.Therefore,the appropriate proportion of unsaturated fatty acids can take into account the film-forming ability and fluidity of droplets.By reducing the change range of the proportion of unsaturated fatty acids,it is found that the proportion of unsaturated fatty acids can regulate the improvement of lubrication performance in stages,but the accurate regulation of lubrication performance is also restricted by many other factors.