摘要
铸态屈氏体高铬铸铁用于水泥磨球已经问世。本文对 Cr13白口铸铁如何得到屈氏体基体组织进行了试验研究。在 Cr 含量一定时,随着 Cr/C 减小,砂型浇注时,过冷奥氏体铸态转变为屈氏体量逐渐增加,金属型浇注时则不易转变。当 Cr/C≤4时,砂型和金属型试样铸态均能得到全部的屈氏体基体。金属型开型后铸件置于550℃炉内保温一定时间随炉冷却,高的 Cr/C 材质亦能得到屈氏体基体组织,但增加了生产工序。加入微量铝可使含碳量在2.6～3.0%的中碳材质砂型和金属型铸件铸态得到屈氏体基体,并有较好的综合性能。
With the coming out of the as-cast high chromium white cast iron with troostite matrix used for grinding cement balls,an experimental investigtion into the ways of obtaining troostite matrix in Cr13 white cast iron has been carried out and is introduced,with Cr concentration being fixed,when metal is poured into a sand mold,the amount of troostite transferred from undercooling austenite gradually increases as the Cr/Cr atio decreases.However,the transformation is not likely to take place in a metal mold.When Cr/C ratios are equal to or less than 4,the matrix of as—casl samples both from sand molds and from metal molds can completely be transferred into troostite.The materials with high Cr/C ratios can also have troostite matrix if the samples from metal molds are kept in the furnace at 550℃ for a certain length of time and then cooled with it.But this requires some further processes.The addition of traces of Al can help the materials containing Cranged from 2.6% to 3.0% obtain troostite matrix both in sand molds and in metal molds.And the materials possess quite satisfactory synthetic properties.
