用金相及电子探针研究了12Cr1MoV在闪光焊时出现的灰斑缺陷,灰斑中存在弥散分布的氧化物夹杂,主要成份是SiO_2和MnO。认为顶锻时氧化物未排挤干净是形成灰斑的原因。用摸拟试验研究了氧化物与钢在液相反应后氧化物中成份的变化规律。讨论了氧化物的最终成份必然是以SiO_2和MnO为主,以及影响灰斑形成的各种因素。 The metallographic and electronic probes were used to study the gray spot defects of 12Cr1MoV during flash welding. There are diffuse oxide inclusions in gray spots, the main components are SiO_2 and MnO. The reason for the formation of gray spots is that the oxide is not squeezed clean during forging. The variation of the composition of oxides in the liquid phase reaction between oxide and steel was studied by means of a mock experiment. It is discussed that the final composition of oxides must be dominated by SiO 2 and MnO, and various factors that affect the formation of gray spots.