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一前言 随着内燃机朝高速、高压缩比和大功率的强化方向发展,对活塞环的性能要求也相应地提高,这样球墨铸铁、蠕墨铸铁、可锻铸铁等高强度铸铁作为活塞环的材质日趋受到活塞环制造者的重视。 在球墨铸铁活塞环筒体、双环铸造中,其显微组织（铸态）常出现球化良好,环的内外圆部位石墨球细小、且量多,珠光体和铁素体较多;环的中心部位石墨球粗大且量少,沿共晶界呈现针状、块状的渗碳体以及莱氏体混合物。也就是我们常说的反白口。 反白口是球墨铸铁活塞环中常见的一种缺陷。它将大大地影响活塞环的韧性,这样不得不借助于高温正火的热处理方式来消除反白口。如何在铸态消除反白口,恐怕也是我们共同关心的问题。
I. INTRODUCTION With the development of high-speed, high-compression ratio and high-power intensification of internal combustion engines, the performance requirements for piston rings have also been correspondingly raised. As a result, the material of high strength cast iron such as ductile iron, compacted graphite cast iron, Piston ring maker’s attention. In the ductile iron piston ring cylinder, double ring casting, the microstructure (as cast) often appear well, the inner and outer ring parts of the graphite ball is small, and the amount of more pearlite and ferrite more; ring Graphite ball at the center of the coarse and small amount, along the eutectic boundary showed acicular, massive cementite and ledeburite mixture. That is what we often say against the white. Anti-white is a common defect in ductile iron piston rings. It will greatly affect the toughness of the piston ring, so have to resort to high-temperature normalizing heat treatment to eliminate the anti-white. How to eliminate the anti-rhetoric in the as-cast state may also be our common concern.