Study On Wear Resistance Of Deep-shovel With Plasma Spraying Nickel-based Coating

With the promotion of protective cultivation technologies, the replacement of plowing with deep scarification has been widely applied along with the increasing use of Deep-shovels year by year. The tip of Deep-shovels may suffer strong wear from the soil layer in operation to lead to serious wear and short lifetime, thus severely affecting the production efficiency and causing many unnecessary losses and energy wastes. Therefore, the study and analysis of the failure mechanism of deep scarificationshovel tips as well as the improvement and optimization of Deep-shovels according to the failure causes are of great significance. Currently, 65 Mn is a most extensively applied agricultural machinery cutter material in China. The abrasion resistance and service life of the cutter is hard to meet the long-term intensive operation requirements of agricultural implements. Failure of the cutter occurs frequently along with high price of the tool, which has become one of the major problems affecting the agricultural production. Therefore, using the surface project rationally to prepare obdurability coatings on the surface of ordinary steel which is with wide use and low cost is of great realistic significance, so as to improve the service life of the tool.This paper mainly adopts the plasma cladding technique to prepare nickel based composite coatings on the surface of deep scarification shovel tips(Ni60+50%WC). Through the orthogonal test, multi-factor analysis of variance and wear test, the optimal technical parameters to prepare(Ni60+50%WC) nickel based composite coatings are obtained: the working current is 130 A, the powder feed rate is 40g/min, the scanning line speed is 130mm/min, the ion gas flow is 0.8m3/h, and the distance between the nozzle and the surface of the work piece is 10 mm.KYKY-2800 scanning electron microscope, optical microscope, HSR-2M reciprocating wear tester, micro hardness tester and electrochemical reaction cell are utilized to test the microstructure, microhardness, wear resistance and corrosion resistance of the cladding layer, results of which show that:(1) The cladding layer treated by the plasma cladding technique and the matrix are with metallurgical bonding which hassatisfactory bonding strength.(2) The maximum microhardness near the cladding layer after plasma cladding technique treatment is HV0.51321. Its microhardness is about four times that of the matrix microhardness.The friction coefficient of the cladding layer is about 1/2 that of the matrix. The cladding layer treated by the plasma cladding technique shows excellent wear resistance property.(3) According to the result of the potentiodynamic electrochemical corrosion test,the corrosion rate of WC nickel based composite coating in 3.5% Nacl solution is 0.04979g·m-2·h-1, which is approximately 1/4 of the corrosion rate of the matrix. Compared to the matrix, it has better corrosion resistance property.Plasma cladding treatment is conducted for the original deep scarification shovel with the optimal technical parameters. The actual field trial is carried out, and a comparison is made to the deep scarification shovel with traditional welding rod technical treatment. The result suggests that the wear resistance property of the deep scarification shovel after optimal technical treatment is about twice that before treatment. The service life has been improved significantly. Although the preparation cost is a quarter more expensive than that with traditional techniques, this technique can be applied to the wear resistance and strengthening treatment on the surface of Deep-shovels considering the comprehensive economic benefits.