| High Strength Steel are widely used in military and civil fields due to the excellent comprehensive mechanical properties. Along with the tendency of complexity, diversification and harshness of the service condition, higher requirements have been putting forward on the performance of the materials. At present, traditional chemical heat treatment method shave many disadvantages, such as low energy utilization rate, low production efficiency, large deformation of workpiece and environmental pollution, while surface coating technology has poor adhesion. As a new type of surface modification technology with high energy and high efficiency, High Current Pulsed Electron Beam(HCPEB) can improve the surface strength, wear resistance and corrosion resistance of parts, which overcomes the defects of traditional surface modification with its own unique advantages.Based on high-strength steel of 50 BA and 30SiMn2 MoV substrate respectively, this paper took use of HCPEB device to remelt the surface of the samples with different number of pulses. Surface and section microscopic morphology, microstructure, wear resistance and corrosion resistance of the samples before and after HCPEB were mainly studied. The results showed that:(1) After HCPEB treatment, craters formed on the surface of samples due to the melt eruption. Craters on the surface of 50 BA high strength steel are scattered, while net-like structure on the 30SiMn2 MoVA samples. With the increasing of pulse number, the number of craters gradually reduced, and the surface micro area became smoother. The size of craters increased and then decreased on the surface of 50 BA samples while decreased on the 30SiMn2 MoVA samples, the net-like structure gradually disappeared and the craters presented state of independent distribution.(2) Phase change had taken place on both the surface of 50 BA and 30SiMn2 MoVA samples so that the martensite and retained austenite appeared. With the increase of pulses, the martensite content reduced, but the content of residual austenite increased. Rapid heating and solidification caused grain refinement, smaller size of the second phase particle and more uniform distribution in the surface layer of the samples.(3) After HCPEB treatment, the surface hardness of all the samples had improved, 50 BA samples had maximum surface hardness,with 50 pulses treatment, increased by 20.9% compared with the original sample; while the maximum surface hardness of 30SiMn2 MoVA samples, increased by 39.6% with 30 pulses treatment. The surface organization consisted of martensite and retained austenite. Both the existence of this hard and soft compound phase and grain refinement could help to improve the surface wear resistance of the samples. Wearing capacity decreased with the increasing of pulses, and the relative wear resistance at least doubled. After 30 and 50 pulses treatment, the relative wear resistance of samples increased 2 times compared with the initial samples. In terms of corrosion resistance, with the increasing of pulse times, corrosion rate and corrosion tendency were reduced due to the reducing of corrosion current density and the increasing of corrosion potential. After 50 pulses treatment, the samples’ surface of 50 BA had the best corrosion resistant performance and the corrosion current density reduced by 43.5%, while after 30 pulses treatment, the samples’ surface of 30SiMn2 Mo VA had the best corrosion resistant performance and its corrosion current density reduced by 48.8%. |
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