Effects Of Microstructure And Properties Of 65Mn Steel Treated By Pulsed-plasma Detonation Technology

65Mn steels have been widely used in mining,agricultural,petroleum and other machinery products due to the advantages of high elastic limit,high hardness,strength and hardenability.However,due to adverse conditions,the artifacts needs to improve its surface life through the surface treatment necessarily.Pulsed-plasma detonation technology is conducted in an atmosphere,to improve the hardness,wear resistance,corrosion resistance and other properties by forming a modified layer on the surface of the material.Modified layer generate after remelting ablation,rapid quenching and ion implantation process by multiple functions of shock wave,pulsed magnetic field,electric field,fast heating and rapid cooling.In this paper,pulsed-plasma detonation technology was introduced to treat the surface of 65 Mn steel.The effects of capacitance,treatment numbers(n),treatment distance(H),on microstructure,phases and performance of the surface modified layer were investigated.A surface modified layer with high hardness and wear resistance was obtained by optimizing the processing parameters of the pulsed-plasma detonation technology.The mechanism of strengthening and toughening of 65 Mn steel surface was also discussed,and which laid a foundation of preparing 65 Mn steel products with high lifespan service life.The results show that:(1)After treated,the modified layer with a thickness of 10~70?m appears on the surface of 65 Mn steel samples.The thickness of the modified layer increased with the increasing of capacitance,treatment numbers and reducing of distance.While the capacitance,treatment numbers and distance were 100%C,2 and 30 mm,the modified layer was thickest,reach to 61.7um.(2)During the process,the diffraction peaks of ?-Fe phase and Fe N phase increase and the ?-Fe phase decrease with increasing treatment energy.The initial ?-Fe in the surface of 65 Mn steel was transformed to ?-Fe,meanwhile,the Fe N and Fe2 N formed attribution to nitriding phenomenon.The mechanical grinding crack was melted and the crateriform pit was discovered on the surface of 65 Mn steel.(3)The microhardness of treated-65 Mn steel has been improved after treated by pulsed-plasma detonation technology.While the capacitance,treatment numbers and distance were 100%C,5 and 50 mm,the maximum hardness of the modified layer was 791.9HV0.01.However,the surface was badly deformed.Relatively better parameters were: capacitance was 100%C,the treatment numbers were 2~5,and the distance were 30~50mm.(4)The friction coefficient,grinding crack width and the wear loss of treated-sample was less than those of the original sample.The wear mechanism was not the result of a single mechanism,but a joint function of abrasive wear,adhesive wear and oxidation wear.The optimum capacitance,treatment numbers and distance are 100%C,2 and 30 mm,respectively,and which leads to the surface roughness and thickness of the surface modified layer are 0.421 ?m,61.7 ?m,respectively.The microhardness is 80% higher than that of the substrate,and the wear loss reduces to half of the substrate.