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碳钢及合金钢经过渗铬后,表面可获得一层结合牢固的铁、铬、碳的合金层(即复合碳化物型的渗铬层),该渗铬层不仅硬度高(HV1400～1800)、耐磨性好,而且还具有良好的抗腐蚀性能、抗高温氧化性能和热疲劳性能,它兼有渗碳、氮化和渗铝的优点,因此,渗铬工艺已成为当今一项重要的表面化学热处理方法,在生产中正在逐步推广应用。一、渗铬工艺方法渗铬方法有气体法、半气体法、液体法和固体法。气体法不仅设备复杂,而且所用的载气给工艺操作带来一些问题(如氯气有毒、氢气易爆炸、氯化氢有腐蚀性),因此在生产中很少采用。目前常用的渗铬工艺有以下三种:1.液体渗铬早期,采用以卤化盐为基的盐浴渗铬法,即在BaCl_2、
After the carbon steel and the alloy steel are infiltrated by chromium, the surface can be obtained with an alloy layer of iron, chromium and carbon (ie, a composite carbides type chromizing layer) which is not only high hardness (HV1400 ~ 1800) , Good wear resistance, but also has good corrosion resistance, high temperature oxidation resistance and thermal fatigue properties, which combines the advantages of carburizing, nitriding and aluminizing, therefore, chromizing process has become an important today Surface chemical heat treatment methods, is being gradually applied in production. First, chromizing process chromizing methods gas method, semi-gas method, liquid method and solid method. The gas method not only has complicated equipment, but also the carrier gas used brings some problems to the process operation (such as poisonous chlorine, explosive hydrogen and corrosiveness of hydrogen chloride), so it is seldom used in production. At present, the commonly used chromizing process has the following three kinds: 1. In the early stage of chromizing liquid, the salt bath chromizing method based on halide salt is adopted, that is,