EA4T车轴钢的超声冲击表面强化

Surface Strengthening Study of EA4T Axle Steel by Ultrasonic Impact Treatment( UIT)

利用超声冲击设备对EA4T车轴钢进行了表面强化处理.采利用金相显微镜和透射电镜表征了车轴钢表面结构的变化,并对超声冲击处理前后试样表面粗糙度和显微硬度进行了分析.结果表明:经超声冲击处理后,试样表面发生了剧烈的塑性变形,晶粒明显细化,显微硬度呈梯度化.随着超声冲击功率的增加,变形层厚度增加,粗糙度减小,表面硬度增大;与未经超声冲击处理的试样相比,在超声冲击功率180瓦作用下,表面粗糙度降低了6.5倍,试样的表面硬度提高了25%,变形层厚度大约为80μm.

The surface strengthening of EA4 T axle steel was processed by ultrasonic impact treatment（ UIT）.Optical microscope and transmission electron microscope were used to characterize the changes of the surface structure,and the surface roughness and micro-hardness of the sample were analyzed before and after UIT.The surface layers of the samples are severely deformed after UIT,the grain size is getting obviously smaller,the surface micro-hardness is decreased gradually,and a gradient structure is formed. With increasing impact power,the depth of plastic deformation layer is increased,the roughness is decreased,and the surface microhardness is increased. Compared to the sample without UIT,the roughness is reduced by 6. 5 times,the surface micro-hardness is raised by 25%,and the depth of plastic deformation layer is about 80μm when the power is 180 w.