Crl8W2白口铸铁耐酸蚀性能初探

采用两种不同含碳量的铸态和正火＋回火处理的Crl8W2白口铸铁在相同条件下进行酸蚀试验。试验结果表明：在pH=1的H2S04溶液中经过200h的酸蚀，含碳量为2．5％的Crl8W2白口铁的酸蚀量大于含碳量为3．3％的Crl8W2白口铁；在pH=l的H2S04溶液中经过200h的酸蚀，含碳量为2．5％和3．3％的Crl8W2白口铁酸蚀量分别趋向4．2-4．6和3．6-3．9μg／（mm2·h）的一个稳定数值范围；Crl8W2白口铸铁的酸蚀机理属于不均匀腐蚀和组织选择性腐蚀，酸蚀主要在相对不耐蚀相马氏体或莱氏体中进行，酸蚀暴露出的碳化物具有良好的抗酸蚀性能。

Preliminary Study of Anti-acid Etching Properties of White Cast Iron Cr18W2

Two kinds of Cr18W2 white cast iron with different carbon content of as-cast and the normalizing ~ tempering were used to do acid etching test. The results suggested that, the acid etching mass-loss value of Cr18W2 with 2. 5%wtC was bigger than that of Cr18W2 with 3.3% after 200 hours eroding in the H2SO4 solution with pH= 1. After 200 hours ero- ding in the H2 SO4 solution with pH= 1, the acid etching mass-loss values of CrlSW2 with 2.5 ~ and 3.3wtC tend to stable values from 4.2-4.6 and 3.6-3.9βg / （mm2.h） respectively. The etching mechanism of Cr18W2 white cast iron be- longs to non-uniform and structure selective corrosion, mainly takes place in the martensite or ledeburite which are easy to be corroded. The acid etched exposed carbides have good anti-etching properties.