通过LOM、XRD、SEM和EDS等手段分析了汽车排气歧管材料的组织构成。高温工作后两种材料尺寸的变化随工作温度的升高逐渐增大,但高硅钼球墨铸铁的尺寸增幅明显大于高镍球墨铸铁的增幅。由于镍和锰能有效提高球墨铸铁的抗氧化性和相变温度,所以高镍球墨铸铁的抗生长性优于高硅钼球墨铸铁的抗生长性。 The composition of automobile exhaust manifold materials was analyzed by means of LOM, XRD, SEM and EDS. After working at high temperature, the change of the size of the two materials increases with the increase of working temperature, but the size increase of high silicon molybdenum nodular cast iron is obviously larger than the increase of high nickel nodular cast iron. Because nickel and manganese can effectively improve ductile iron oxidation resistance and phase transition temperature, the anti-growth of high-nickel ductile iron is better than that of high-silicon molybdenum ductile iron.