| China as a large agricultural country agricultural modernization level urgently needs to be improved,agricultural modernization must rely on agricultural mechanization.Complex agricultural working conditions can make mechanical equipment in the work of a series of problems such as wear and tear,not only there is a certain safety risks,while limiting the service life of agricultural machinery.In order to further enhance the use of agricultural machinery efficiency and service life,to solve the damaged as agricultural machinery parts of the 316 L austenitic stainless steel surface repair problem,proposed the use of electro-spark deposition technology to repair 316 L austenitic stainless steel surface defects.As a surface treatment technology with its unique advantages,electro-spark deposition technology is widely used in the preparation of mechanical equipment substrate surface coating and defect repair,which can enhance the substrate surface wear resistance,surface corrosion resistance,surface oxidation resistance,improve the surface hardness and a series of physical and chemical properties.In this paper,austenitic stainless steel coatings were prepared on the surface of 316 L austenitic stainless steel using electro-spark deposition technology and surface defects of austenitic stainless steel were repaired.The main research contents and results are as follows:(1)Through the L16(43)ESD deposition orthogonal test,and the quality of the prepared coating is rated to conclude that the best process parameters for the preparation of 316 L austenitic stainless steel coating are: capacitance 3000 μF,voltage 20 V,deposition time 90 s;the influence of the three parameters on the preparation of austenitic stainless steel coating is mainly: voltage > capacitance > deposition time.According to the orthogonal test,the optimum parameters are: the weight and thickness of the coating increases with the increase in capacitance and then decreases,and increases with the increase in voltage and deposition time.The hardness of the coating decreases linearly with increasing capacitance,increases linearly with increasing voltage,and increases and then decreases with increasing deposition time.(2)Based on orthogonal tests to investigate the effect of atmospheric protection(Ar)on the preparation of coatings,it was concluded that the use of Ar protection for deposition of coatings can reduce oxidation,reduce the burn damage to the substrate,make the deposited coating uniform and dense,and reduce the presence of cracks and holes in the coating.The weight of the coating deposited with Ar protection was 46 mg,the thickness of the coating was approximately 50 μm and the average hardness reached352.1 HV.XRD,electro-spark deposition surface and line sweeps of the coating and substrate showed that the austenitic phase of the coating material was not altered by the ESD technique.(3)Eight sets of defect repair experiments with 3 factors and 2 levels and a quality rating of the repaired layer showed that the best process parameters for repairing defects were: voltage 20 V,capacitance 3000 μF,vibration and Ar protection,with a microhardness of 311.4 HV.The repaired layer showed a strong metallurgical bond with the substrate and a high bond strength.The repair layer is basically free of defects.The electro-spark deposition technique is therefore suitable for the repair of surface defects in 316 L austenitic stainless steel.(4)Through the optimal process parameters deposited austenitic stainless steel coating and the substrate 316 L austenitic stainless steel plate wear weight loss,friction coefficient,wear surface microscopic morphology analysis: the wear weight loss of the coating is 1.3 mg lower than the substrate 1.5 mg;coating the average friction coefficient of 0.434,also lower than the substrate 316 L austenitic stainless steel plate0.513;coating and The surface morphology of the coating and substrate abrasion marks can visually show that the wear resistance of the coating is better than that of the substrate;therefore the wear resistance of the austenitic stainless steel coating prepared by electro-spark deposition technology is slightly better than that of the substrate 316 L austenitic stainless steel plate. |
PDF Full Text Request