汽车半轴用合金结构钢的开发

针对汽车半轴用合金结构钢质量要求高的特点，电炉冶炼采用全程造泡沫渣及留钢、留渣操作，控制终点碳；LF炉喂CaSi线复合脱氧，吹氩处理；连铸过程采用低过热度、全程保护浇注；大压缩比轧制。质量检验表明，开发的40CrH钢化学成分均匀，力学性能、淬透性能良好，且波动范围窄；晶粒度7级以上，非金属夹杂物含量低，平均氧含量18.3×10^-6。产品质量完全满足用户使用要求。

Development of the Alloy Structural Steel for the Automobile Semi-axis

Aiming at the high quality requirement of the alloy structural steel for automobile semi-axis, a series of quality control measures were took in developing course, such as, adopting foaming slag in the whole process and remaining steel and slag operation in electric furnace smelting; composite deoxidation by feeding CaSi wire and blowing argon treatment in ladle furnace process, using low degree of superheat and overall-protective casting in continuous casting process and adopting a large compression ratio in rolling process. The quality inspection showed that the developed 40CrH steel had even chemical composition, good mechanical properties and hardenability, and narrow fluctuated range; The grain size was 7 grade or more, non-metallic inclusions content was low and the average oxygen content was 18.3 × 10^-6; The product quality met user requirements completely.