强流脉冲电子束表面改性 1. 2344 钢的显微组织和性能

目的在1.2344钢表面获得一层硬度较高的强化层。方法利用强流脉冲电子束技术,在相同的加速电压下,采用不同的脉冲次数对1.2344钢表面进行改性处理,研究处理前后样品的表层显微组织和性能变化规律。结果经强流脉冲电子束处理后,试样表面形成了形状各异、大小不一、分布不均的熔坑,并且随着脉冲次数的增加,熔坑数量逐渐减少,熔坑的直径变大。当脉冲次数大于50次时,试样表面出现奥氏体相,表面显微硬度提高了14.5%。结论强流脉冲电子束处理可使试样表层的晶粒变小,晶粒细化和表面宏观残余应力的共同作用促使试样显微硬度增加。

Microstructure and Properties of 1. 2344 Steel Modified by High-current Pulsed Electron Beam

Objective To obtain a strengthened layer with high hardness on the surface of 1. 2344 steel. Methods 1. 2344 steel was irradiated with uniform accelerating voltage and different pulses using high-current pulsed eletron beam. The variation rules of surface microstructure and performance of the sample before and after modification were studied. Results It turned out that the surface of the samples formed some crater-like defects which had different shapes, sizes and nonuniform distruction after irradiation by HCPEB. The number of crater-like defects was decreased and the diameter was increased with the increasing irradiating pulse. Austenite appeared on the surface of the irradiated samples, and the surface microhardness was increased by nearly 14. 5% when the pulse frequency exceeded 50. Conclusion After processing with high-current pulsed electron beam, the size of the grain was reduced in the surface layer of the sample. The microhardness of the specimen was increased due to the grain refinement and the generation of macroscopic residual stress.