电弧炉系列-废钢要求

Scrap is the main material for EAF steelmaking.Scrap quality has a direct impact on steel quality,cost and furnace productivity.Therefore there are following requirements on scrap quality.

(1)The surface of scrap steel should be clean and less rust,because some sand and other sundries in scrap will reduce the conductivity of the charge,prolong the melting time,but also affect effect of phosphorus removal at the oxidation period,moreover cause erosion of the lining.Heavy rust or oil stains may increase the hydrogen content of steel.

(2)Nonferrous metals such as lead,tin,arsenic,zinc and copper shall not be mixed into scrap.Lead has high density,low melting point and is insoluble in molten steel.Tin,arsenic and copper easily cause hot-brittle steel.

(3)Sealed containers,flammable,explosive and toxic materials shall not be mixed in the scrap to ensure safe production.

(4)The chemical composition of scrap should be clear and the sulfur and phosphorus content should not be too high.

(5)The external dimensions of scrap shall not be too large(not exceed 150mm×150mm,and the maximum length is less than350mm).In EAF steelmaking process,pig iron is generally used to increase the amount of carbon in the charge,which usually does not exceed30%of the charge.

废钢是电弧炉炼钢的主要材料，废钢质量的好坏直接影响钢的质量、成本和电炉生产率，因此，对废钢有如下几点要求：

(1)废钢表面应清洁少锈，因废钢中沾有的泥沙等杂物会降低炉料的导电性能，延长熔化时间，还会影响氧化期去磷效果以及侵蚀炉衬。废钢锈蚀严重或沾有油污时会降低钢和合金元素的收得率，增加钢中的含氢量。

(2)废钢中不得混有铅、锡、砷、锌、铜等有色金属。铅的密度大，熔点低，不溶于钢液，易沉积在炉底缝隙中造成漏钢事故。锡、砷和铜，易引起钢的热脆。

(3)废钢中不得混有密封容器，易燃、易爆物和有毒物，以保证安全生产。

(4)废钢化学成分应明确，硫、磷含量不宜过高。

(5)废钢外形尺寸不能过大(截面积不宜超过150mm×150mm，最大长度不宜超过350mm)。生铁在电弧炉炼钢中，一般被用来提高炉料的配碳量，通常配入量不超过炉料的30%。