Research On Surface Alloying Of9310Carburizing Bearing Steel By High Current Pulsed Electron Beam

In order to decrease the cracks occurred in the surface of carburized steel duringgrinding, high current pulsed electron beam (HCPEB)、magnetron sputter method andmulti-arc ion plating technology were employed to alloying Ti、TiWTaNb and Zr on thesurface of9310carburized steel. The microstructure of the allying layer wascharacterized using scanning electron microscopy(SEM)、X-ray diffraction(XRD), themechanical performance and corrosion behaviors were measured by friction machineand electrochemical experiments, respectively.The irradiation energy and times have evident influence on the surface morphology.Crater-like defects appeared on the surface of allying layer. The density of the defectsdecreased rapidly along with the irradiation energy or times increase, but did notdisappear. Under the irradiation energy of3J/cm~2, Ti melt down barely; the allyingcomes while the irradiation energy rose to6J/cm~2; when the irradiation energy comes to9J/cm~2, alloying element were vaporized and very little left. The thickness of alloyinglayer depends on the energy of irradiation instead of irradiation numbers.The results of XRD show that austenite formed while martensite transformation isdepressed. Because of the eruption or dissolution of carbides, the alloying layer mainlymade up by solid solution of Fe.Under dry sliding contact conditions, the samples performed differently. Thefriction coefficient of untreated sample is about0.8, but the Ti alloying samples cankeep a low coefficient of0.2by1000~5000rounds, while the TiWTaNb alloyingsamples keep in0.2by15000rounds. The wear coefficient of alloying samplesdecreases by2/3compared with untreated samples. The main wear mechanisms areoxidation wear.The corrosion resistance promoted except that samples with defects under lowirradiation times. The Corrosion resistance of the alloying layer increased with theirradiation times. Under the same irradiation times, the irradiation energy of3~6J/cm~2was the best, corrosion potential rose by50mV, corrosion current density declined oneorder of magnitude.Tempering treatment could assist the decomposition of the retained austenite underthe temperature of575to600℃, carbides precipitated at600℃, the surface hardness reached the highest.