【摘要】 通过改变高铬铸铁(Cr15)的含碳量,研究了高铬铸铁凝固过程中初生奥氏体中C、Cr量变化对初生奥氏体稳定性的影响。结果表明,较快的冷速条件下自液体中析出的初生奥氏体固溶的C、Cr量远高于平衡条件;在本试验冷却条件下,随着碳含量的增加,初生奥氏体中固溶的C量增加、Cr量减少,这使C原子的扩散增强,并且奥氏体过饱和程度增大,二次碳化物析出趋势增强;当二次碳化物未析出时,碳量的增加使奥氏体稳定性增加,而一旦二次碳化物析出,碳量的增加使奥氏体的稳定性变差;碳量2.63%为奥氏体能否析出二次碳化物的临界值。更多还原

【Abstract】 The effects of carbon and chromium concentration distribution in primary austenite on its stability during solidification are investigated by changing the carbon content of high chromium cast iron(Cr15).The results show that the rapider freezing rate is,the more carbon and chromium solute in primary austenite;under our experimental conditions,the solubility of carbon increases and that of chromium decreases in primary austenite as carbon content increases,which enhances the diffusion of carbon and makes the supersaturation rise,and secondary carbides are easy to precipitate.The increase of carbon content leads to primary austenite more stable when no secondary carbides precipitating,however,once secondary carbides precipitate,it results in the instability of primary austenite.2.63%C is the critical value whether the austenite precipitates secondary carbides.更多还原