Study On The Tribological Properties Ofthe Material In Agricultural Mechanical Contact With Ultrasonic Assisted Equal Channel Angular Extrusion

In agricultural machinery,soil wear on earth-contact components causes a lot of economic losses and also affects production efficiency.Wear also causes frequent failure of the earth-moving parts of agricultural machinery and increases operating costs.The wear problem is a technical problem that needs to be solved urgently in the field of agricultural machinery.At present,domestic and foreign methods for improving the wear resistance of earth-machined components of agricultural machinery mainly are by adoptting high-strength and wear-resistant materials or strengthening the surface or heat treatment to improve their wear resistance.These methods have improved agricultural mechanical touch to some extent.The strength and hardness of the earth components improve the wear resistance of the surface,but these surface treatments do not achieve the desired results.Due to the unstable treatment effect,inconsistent surface structure of the surface layer and the matrix material,and poor toughness of the surface material,these will affect the overall performance of the earth-contact components of the agricultural machinery and the service life cannot be improved.Therefore,the strength,toughness,hardness,etc.of the earth-contacting parts of agricultural machinery not only affect the mechanical properties of the materials,but also determine the friction and wear properties of the decisive factors.To solve this problem,ultrasonic-assisted equal channel angular extrusion was carried out.Study on the Abrasion Resistance of Substrate Substrate in Agricultural Machinery.Ultrasonic vibration plastic processing can reduce the friction between the mold and the workpiece and improve the metal processing performance.The iso-channel corner extrusion process achieves ultra-fine grain structure by causing large plastic deformation of the metal material.In this paper,the die of ultrasonic-assisted equal channel angular extrusion was designed by means of ultrasonic technology and equal channel angular extrusion technology.Through this die,the soil contact parts of agricultural machinery were subjected to extrusion treatment to effectively refine the 65 Mn of agricultural machinery contact parts.The microstructure of the steel,in turn,improves the wear resistance of the 65 Mn steel used in agricultural machinery contact parts.The main research contents and conclusions are as follows:(1)The process of ultrasonic-assisted equal channel angular extrusion was used to extrude the substrate of agricultural machinery in contact with earth.The microstructure was observed and analyzed to study ultrasonic vibration,preheating temperature,friction and wear and annealing temperature,and annealing time.The influence of the ultrasonic-assisted equal channel angular extrusion on the substrate processing of agricultural machinery in contact with earth parts was determined,and the ultrasonic-assisted equal channel angular extrusion process was used to refine the contact parts of agricultural machinery.The mechanism of the microstructure of the substrate.The results showed that the ultrasonic-assisted equal channel corner extrusion treatment of agricultural machinery in contact with the base material at 950 °C high temperature heat treatment,the smooth implementation of the extrusion process,agricultural machinery in contact with the substrate grain is significantly refined,grain The size is significantly reduced.(2)Analyze systematically the changes in the hardness and mechanical properties of the substrate of agricultural machinery in contact with agricultural machinery after ultrasonic-assisted equal channel angular extrusion,and clarify the impact of ultrasonic-assisted equal channel angular extrusion on the mechanical properties of the ground-contact parts of agricultural machinery.The mechanism of performance.The experimental results show that due to grain refinement,the hardness of the substrate of the earth-contact parts of agricultural machinery increases;when the annealing temperature is 774°C,the hardness increases;due to the application of ultrasonic vibration,the ultrasonic-assisted equal channel angular pressing load of the 65 Mn steel is significant.decline.Ultrasound-assisted equal channel angular pressing has significantly improved the mechanical properties of earth-contact components in agricultural machinery.(3)From the perspective of microstructure,the impact of ultrasonic-assisted equal channel angular extrusion compression on the second phase of soil contact parts in agricultural machinery was discussed.The results showed that the two-phase structure in the substrate of agricultural machinery contact parts was significantly refined by ultrasonic-assisted equal channel angular extrusion pressing.The strong plastic deformation caused a large number of dislocations in the microstructure of the 65 Mn steel.With the annealing temperature,ultrasonic The vibration applied,the precipitated second phase is dispersed in the matrix,which helps to refine the microstructure of the matrix material and plays a role of dispersion strengthening on the matrix material.The diffusion distribution of the second phase particles also contributes to improve the mechanical properties of the 65 Mn steel.(4)systematically studied the tribological properties and wear patterns of the substrate of the agricultural machinery in contact with the agricultural machinery under dry friction conditions after ultrasonic assisted equal channel angular extrusion.The results showed that the ultrasonic-assisted equal channel angular extrusion process significantly improved the tribological performance of the substrate of agricultural machinery in contact with soil.Under dry friction conditions,the tribological performance of the agricultural machinery contact parts subjected to ultrasonic-assisted equal channel angular extrusion was improved.Both are significantly superior to the tribological performance of agricultural machinery in contact with untreated and single-pass channel corner extrusions.Under the conditions of dry friction and certain loads,the wear forms of 65 Mn steel specimens without ECAE treatment,ECAE treatment,and ultrasound-assisted ECAE treatment are mainly abrasive wear.The former two abrasive wear are relatively serious and occur at different levels.Adhesive wear was observed,but the wear of the 65 Mn steel sample treated with ultrasound-assisted ECAE was slight.(5)The mechanism of the influence of ultrasonic assisted equal channel angular extrusion process on the friction and wear properties of 65 Mn steel specimen was discussed.The technology of ultrasonic assisted equal channel angular extrusioncan significantly refine the apparent microstructure of 65 Mn steel specimens.The diffusion distribution of second-phase particles plays an important role in strengthening the 65 Mn steel,weakening the degree of adhesive wear,and reducing the wear of 65 Mn steel specimens;the microstructure of the treated 65 Mn steel with ultrasonic assisted ECAE was significantly refined,and the microhardness was improved.It improved the resistance of the 65 Mn steel to plastic deformation and reduced the abrasive wear,and improved the friction and wear properties of the 65 Mn steel.