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目的研究强流脉冲电子束(HCPEB)对50BA钢表层组织和表面耐腐蚀性能的影响。方法对50BA钢进行不同脉冲次数的表面处理,用扫描电镜观察组织变化,并在NaCl和去离子水配成的3.5%NaCl腐蚀溶液中(室温)进行动电位极化曲线测试。结果经HCPEB处理后,50BA钢试样表层晶粒细化且产生了细小均匀分布的针状马氏体,随着脉冲次数的增加,表面趋于光滑。试样表面的自腐蚀电位从-0.660 V提高到-0.629 V,腐蚀电流从1.48×10~(-6) A降低到8.36×10~(-7) A。随着脉冲次数的增加,试样表面的腐蚀电流降低,腐蚀电位升高,腐蚀速率降低,腐蚀倾向性减小,其中50次脉冲处理后试样表面的耐蚀性能最好。结论经HCPEB处理后,表层组织发生相转变,表面趋于光滑和获得的均匀细小针状马氏体从理论上解释了50BA钢耐腐蚀性能的提高。为了提高50BA钢的耐腐蚀性,应将脉冲次数控制在30次以上,且越高越好。
Objective To study the effect of high current pulsed electron beam (HCPEB) on the microstructure and surface corrosion resistance of 50BA steel. Methods The surface of 50BA steel was treated with different pulse times. The changes of microstructure were observed by scanning electron microscopy. The potentiodynamic polarization curve of 50BA steel was tested in 3.5% NaCl solution (NaCl) mixed with deionized water. Results After HCPEB treatment, the grain size of the 50BA steel sample was refined and the fine and uniform needle-like martensite was produced. As the pulse times increased, the surface became smooth. The corrosion potential of the sample surface increased from -0.660 V to -0.629 V, and the corrosion current decreased from 1.48 × 10 -6 A to 8.36 × 10 -7 A. With the increase of the number of pulses, the corrosion current on the sample surface decreases, the corrosion potential increases, the corrosion rate decreases, and the corrosion tendency decreases. The corrosion resistance of the sample surface after 50 pulses treatment is the best. Conclusions After HCPEB treatment, the phase transformation of the surface tissue and the smooth surface and uniform fine acicular martensite obtained theoretically explain the improvement of corrosion resistance of 50BA steel. In order to improve the corrosion resistance of 50BA steel, the number of pulses should be controlled more than 30 times, and the higher the better.