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灰铸铁缸套是刹车气泵中的关键零件,要求具有良好的耐磨性及足够的强度,一般要求硬度为HB170～240。我厂生产的缸套常因硬度低而成批报废,给企业造成很大的经济损失。为解决这一问题,我们试验了正火工艺,经生产使用后,效果良好。为增加缸套耐磨性,我们采用在普通灰铸铁中加入一定量铜和锰的合金铸铁,其基体组织为珠光体加片状石墨,这是一种较理想的组织,其性能较好。当浇铸温度较高,冷却缓慢时,由于石墨析出较多,化合碳较少而形成珠光体、铁素体和片状石墨的组织,铁索体硬度为HB80～100,它的出现,降低了铸件硬度,使铸件机械性能变差。为此,对因硬度低而报废的缸套,我们采用正火
Gray cast iron cylinder liner is a key component of the brake pump, requires good wear resistance and sufficient strength, the general requirements for hardness HB170 ~ 240. Our factory production of cylinder often because of low hardness and batch scrap, to the enterprise caused great economic losses. In order to solve this problem, we tested the normalizing process, the result is good after production and use. In order to increase the wear resistance of the cylinder liner, we adopt the alloy cast iron with a certain amount of copper and manganese added to common gray cast iron. The matrix structure is pearlite and flake graphite, which is an ideal structure and has better performance. When the casting temperature is high, the cooling is slow, due to more graphite precipitation, less co-formed carbon and pearlite, ferrite and flake graphite organization, ferrite body hardness HB80 ~ 100, it appears, reducing the casting Hardness, so that poor mechanical properties of castings. To this end, due to low hardness and scrapped cylinder liner, we use normalizing