零夹杂钢精炼的理论与工艺

Theory and process of refining zero inclusion steel

零夹杂钢即夹杂物高度弥散分、尺寸小于1μm的钢。论文从理论上分析其制备的可能性,展望其性能。具体工艺措施为:经过预脱铝处理的超低S、P工业纯铁,在50kg真空感应炉中依靠碳氧脱氧反应进行初脱氧、深脱氧和合金化处理,炼成42CrMo钢,最后在电子束炉中经过两次重熔,得到全氧量为T.O.=4×10-6的42CrMo锭。精炼钢锻造成材后,非金属夹杂物非常细小用常规金相检验(×100倍)很难定量评级,在扫描电镜检测下发现有少量1～4μm的Al2O3夹杂,其主要来自铁合金原料。疲劳寿命由107转数提高到109转数。

The zero inclusion steel is such a steel of which the inclusions in matrix are highly dispersed with the inclusion size less than 1 micron. The possibility of refining zero inclusion steel is discussed theoretically with its properties expected. A refining process was therefore conducted as follows. The ingot iron containing extra-low sulfur and phospnorus, which has been pretreated with dealuminization, is refined into the steel 42CrMo in a 50 kg vacuum induction furnace by way of primary and secondary deoxidizations using carbon and alloying process. Then, the steel is remelted twice in a vacuum electron-beam melting (EBM) furnace to obtain 42CrMo steel ingots of which the total oxygen content T.O.=4×10^(-6) in wt.%. After forging them up, the size of their non-metallic inclusions are so small that they cannot be graded by conventional metallographic examination with a magnification up to 100. However, by virture of SEM, there are few alumina of 1～4 micron found in these ingots as inclusions mainly from ferroalloy. The fatigue limit of such ingots can thus increase to 10~9 rev. from 10~7 rev.