对球墨铸铁表面进行超声加工处理，通过白光共焦三维显微镜、扫描电子显微镜、光学显微镜和维氏硬度计等研究了加工区和未加工区的三维形貌、表面粗糙度、显微组织等。结果表明：超声加工对试样的尺寸影响很小，可实现连续抛光；加工区与未加工区的交界处有高约30 μm的蝶形凸起；超声加工能显著降低试样的表面粗糙度，轮廓算术平均偏差由加工前的1.465 μm减小到0.948 μm，降低了35.29%；超声加工后，试样表层晶粒明显细化，表面硬度提高，超声加工对试样硬度的影响深度为0.6 mm左右。

The surface of ductile cast iron was treated by ultrasonic machining. The three-dimensional morphology, surface roughness and microstructure of the surface of non-machining area and machining area were studied by using white light confocal microscope, scanning electron microscope, optical microscope and Vickers hardness tester. The results show that the ultrasonic machining had little effect on the size of the sample, and the continuous polishing was achieved. The transition zone between non-machining area and machining area had a butterfly shaped protrusion with height of about 30 μm. The surface roughness of the sample was reduced by ultrasonic machining significantly. The arithmetical mean deviation of the profile changed from 1.465 μm before machining to 0.948 μm, being reduced by 35.29%. The grains in the surface layer of the sample were refined obviously after ultrasonic machining; the surface hardness of the sample increased. The effect depth of ultrasonic machining on the hardness of the sample was about 0.6 mm.