阿拉尔耕地沙土与65Mn摩擦行为的研究

Friction Behavior between Cultivated Sand and 65Mn in Alaer

目的探究阿拉尔耕地沙土与65Mn的摩擦学行为,为高速犁结构设计、优化和材料选择提供理论基础。方法采用摩擦磨损试验机,选择土壤含水率、平均粒径、载荷、转速和摩擦时间等5个参数进行单因素多水平试验,研究沙土对65Mn的摩擦行为,并对各因素水平下金属磨损形貌进行分析。结果随着含水率的增加,土壤黏附力和润滑水膜的厚度增大,摩擦因数减小,磨损量呈二阶抛物线规律;随着平均粒径的增加,微观接触面积减小,摩擦因数、磨损量与粒径呈负相关;随着载荷的增加,磨料挤压嵌入金属表面,使得微观切削量增加,摩擦因数呈小幅上升趋势,磨损量呈大幅上升趋势;随着转速的增加,摩擦因数、磨损量变化较缓和;随着摩擦时间的增加,因热量的累积,摩擦因数和磨损量呈上升趋势,土壤与金属的摩擦逐渐演变为土壤之间的摩擦。分析磨损形貌发现,65Mn金属磨损表面始终伴随着磨料磨损造成的犁沟、疲劳和剥落,还发现了腐蚀磨损造成的裂纹,表面金属材料被腐蚀成金属盐结晶体,2种形式的磨损交互影响,加剧了65Mn的磨损。结论方差分析表明,与土壤含水率、载荷、转速相比,平均粒径和摩擦时间对沙土与65Mn的摩擦因数的影响较大,平均粒径对65Mn的磨损的影响最大。

The friction behavior between soil and metal widely exists in the work of the soil contact component of agricultural machinery,and the wear of the share parts of the high-speed plow is especially serious in the sandy soil.Because the composition of the soil is complicated,the material and processing technology of plow parts are different,and the working conditions change from time to time in actual farming,the friction behavior between sand and plow parts is very complicated.The work aims to explore the friction behavior of cultivated sand and 65Mn in Alaer,so as to provide a theoretical basis for structural design,optimization and material selection of high-speed plow.Friction and wear testing machine was used in this study.Soil water content(6%,10%,14%,18%,22%),mean particle size(0.1,0.2,0.3,0.4 mm),load(50,100,150,200,250 N),rotational speed(30,60,90,120,150 r/min)and friction duration(10,20,30,40,50 min)were selected to study the friction behavior of sand to 65Mn by single-factor multi-level tests,and the metal wear morphology was analyzed under each factor level.The results showed that with the increase of soil water content,the soil adhesion and lubricating water film increased,the friction coefficient showed an overall downward trend,and the wear amount showed a second-order parabola law.With the increase of average particle size,large-scale abrasive played the role of bearing load,the microscopic contact area decreased,and the friction coefficient and wear amount were negatively correlated.With the increase of load,the micro-cutting or abrasive breaking of the contact surface increased,the friction coefficient increased slightly,and the wear amount increased significantly.With the increase of rotational speed,the friction heat change caused by the speed did not cause the annealing and tempering effect of the metal,and the change of friction coefficient and wear amount was moderate.With the increase of friction time,the friction coefficient and wear amount increased due to the accumulation of heat,and the distribution of water between soils was uneven due to friction heat,so the friction between soil and metal gradually evolved into the friction between soils.At the same time,the wear morphology analysis found that the wear surface of 65Mn metal was always accompanied by furrow,fatigue and spalling caused by abrasive wear.After a long period of friction,it was found that the salt carried in the soil caused corrosion on the metal,the metal surface cracked,and the metal was corroded into metal salt crystals.Abrasive wear and corrosion wear interacted and aggravated the wear of 65Mn.In addition,the friction coefficient and wear amount under each factor level were analyzed by single-factor ANOVA.Compared with soil water content,load and rotational speed,the average particle size and friction time had greater effect on the friction coefficient between sand and 65Mn.The average particle size had the greatest effect on the wear of 65Mn.