Surface Modification Of T8 Steel By Pulse Detonation-Plasma Technology

Pulse detonation-plasma technology is a relative cheap and easy technique for improving hardness value and tribological property. It was recognized by high energy efficiency, simple treatment without any pretreatment and the different kinds of plasma obtained by adjustment of parameters. Therefore, pulse detonation- plasma technology was considerably scientific and practical.The thesis is mainly on the research that modifies the surface properties of T8 steel by pulse detonation-plasma technology with different capacity, treat times and distance. The surface feature, structure, the micro-hardness, wear and friction properties and the corrosion resistance were detected by metallurgical microscope, X-ray diffraction, SEM, energy disperse spectroscopy, abrasion tester and electrochemical workstation. The results show that:(1)The initial ?-Fe in the surface of T8 steel was changed into ?-Fe, and Fe3 N after pulse detonation-plasma treatment, at the same time, the mechanical grinding crack was melted and the crateriform pit was discovered on the surface of T8 steel.(2)Bistratal modified layer was formed on the surface of T8 steel after pulse detonation-plasma treatment, the bistratal modified layer consisted of columnar zone and fine grain zone. The maximum thickness of modified layer is 68.27 ?m when the parameters was C=1000 ?F,n=2, H=50 mm, the thickness of columnar zone was 26.86 ?m and the thickness of fine grain zone was 41.41 ?m. The average grain size of modified layer was 1/5 of substrate, only1 0.28 ?m.(3)After pulse detonation-plasma treatment(C=1000 ?F,n=2, H=50 mm), microhardness of surface of T8 steel was significantly improved. The maximum hardness of modified layer was up to 909 HV, it was 2.26 times of the hardness of the initial T8 steel.(4)Abrasive resistance of T8 steel was obviously improved by pulse detonation-plasma treatment, the abrasion loss of modified T8 steel was 38.3-84.1% of untreated T8 steel at the same wear conditions.(5)In consideration of surface hardness, abrasive resistance and thickness of modified layer, the optimum technology parameter was C=1000 ?F,n=2, H=50 mm.