Scrap is the main material for EAF steelmaking. Scrap quality has a direct impact on steel quality, cost and furnace productivity. Therefore scrap should meet following requirements before charged.
- The surface of scrap steel should be clean and less rust, sand and other sundries in scrap will reduce the conductivity of the charge, prolong the melting time, but also influences 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.
- 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
- Sealed containers, flammable, explosive and toxic materials shall not be mixed in the scrap toensure safe production.
- The chemical composition of scrap should be clear and the sulfur and phosphorus content should not be too high.
- The external dimensions of scrap shall not be too large ( not exceed 150mm℅150mm, and the maximum length is less than 350mm). In EAF steelmaking process, pig iron is generally used to increase the amount of carbon in the charge, which usually does not exceed 30% of the charge.
