材料期刊网

以U75V高速重轨为例，对冶炼过程的全氧含量和夹杂物的形貌、尺寸及成分进行了系统分析，对重轨钢精炼过程的脱氧与夹杂物控制进行了探讨。结果表明，炉渣碱度高有利于Si的脱氧， LF精炼后可将钢中全氧含量降至15ppm以下，但高碱度会导致钢中脆性夹杂物增多；高真空虽然对碳脱氧有利，但易引起钢中Al含量升高，不利于夹杂物的形态控制。RH与LF相比，排除小颗粒夹杂的能力更强，RH精炼后，钢中的夹杂物已经非常细小，保护浇注的力度和中间包去夹杂能力是最终决定钢中是否存在大型夹杂物的关键。高速重轨钢的冶炼可以在LF精炼过程中采用较高的炉渣碱度，而在RH精炼过程中，应适当降低炉渣碱度和减少精炼时间。

The total oxygen and the image、the size and composition of the inclusion was studied systematically from an example U75V of high rate heavy rail steel during the smelting process, deoxidization and inclusion control was discussed in the course of heavy rail steel refining. The results show that high basicity slag is propitious to deoxidization by Si that the total oxygen is under 15ppm in steel after LF refine, but high basicity also induce to increase the fragile inclusion in steel; although high vacuum is propitious to deoxidization by carbon, it can also cause the aluminum content increased in steel and is harmful to control inclusion morphology. In the ability of removal of fine inclusion RH refining is better than LF refining and the inclusion is very small after RH refining, the strength of protecting cast and the ability of removal of inclusion in tundish is a key that decides if the large inclusion exists in final steel. During the high rate heavy rail steel smelting, the upper basicity slag can be used during the LF refining, but it reduces suitable basicity of slag and refining time during the RH refining.