论文部分内容阅读
国内的汽缸套生产大多采用离心铸造,所得组织,石墨大多属于B型。第二汽车厂东风牌汽车的缸套要求内部组织为A型石墨,我厂以多种工艺进行试验,以一种简单而廉价的方法获得了成功。一、化学成分的选择 所谓共晶团是由片状石墨周围包围着共晶奥氏体而构成的,但石墨片的尖端部分是在与液体保持着接触的情况下长大的。因此要得到A型石墨必须在共晶转变开始时有较多的液态合金。因此,越接近共晶成分,到共晶转变时保持液态部分也就越多,也愈容易获得A型石墨。显然一般生产缸套的化学成分都是可以获得A型石墨的。也就是;C3.1～3.5％,Si2.0～2.4％都可得到A型石墨,而S则越低越好。 从理论上来说,硼缸套比磷缸套更难得到A型石墨,不过我们在试制中,硼缸套同样可获得A型石墨。二、用阻热性能好并能产生还原性气体的涂料 涂料的成分见表。
Most domestic cylinder liner production by centrifugal casting, the resulting organization, most of graphite belongs to the B type. The second automobile plant Dongfeng brand of cylinder liner requires internal organization for the A-type graphite, I plant to test a variety of processes, in a simple and inexpensive way to be successful. First, the choice of chemical composition The so-called eutectic group is surrounded by flake graphite eutectic austenite and constituted, but the tip portion of the graphite sheet is maintained in contact with the liquid grew up. Therefore, to get A type graphite must have more liquid alloy at the beginning of eutectic transformation. Therefore, the closer the eutectic composition is, the more the liquid portion remains until the eutectic transformation, and the more the A-type graphite is obtained. Obviously the chemical composition of the general production of cylinder can get A-type graphite. That is, C3.1 ~ 3.5%, Si2.0 ~ 2.4% are available A-type graphite, and S is as low as possible. In theory, boron cylinder liner is more difficult to obtain type A graphite than phosphorus cylinder liner, but we also get type A graphite in the trial production. Second, with a good thermal performance and can produce a reducing gas paint coating composition shown in the table.