(1) The surface of scrap steel should be clean and less rusty, because the debris such as sand and sand in the scrap steel will reduce the conductivity of the furnace charge, extend the melting time, and affect the dephosphorization effect during the oxidation period and erode the lining. When the scrap steel is severely corroded or stained with oil, it will reduce the yield of steel and alloy elements and increase the hydrogen content in the steel.

(2) Lead, tin, arsenic, zinc, copper and other non-ferrous metals shall not be mixed in scrap steel. Lead has a high density, a low melting point, is insoluble in molten steel, and is easy to deposit in the gap at the bottom of the furnace, causing a steel leakage accident. Tin, arsenic and copper can cause hot brittleness of steel.

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

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

(5) The overall dimensions of the scrap steel should not be too large (the cross-sectional area should not exceed 150mm × 150mm, and the maximum length should not exceed 350mm). Pig iron is generally used in electric arc furnace steelmaking to increase the amount of carbon in the charge, and usually the amount does not exceed 30% of the charge.

Preparation work before smelting

The batching is an indispensable part of the graphite electrode steelmaking process. Whether the batching is reasonable is related to whether the steelmaker can normally perform the smelting operation according to the process requirements. Proper ingredients can shorten the smelting time. Attention should be paid to the batching: First, the batching calculation must be performed correctly and the charging amount of the furnace charge must be accurately weighed. The second is that the size of the charge should be matched in proportion to achieve the purpose of good installation and quickening. The third is that various types of furnace charge should be used in accordance with the quality requirements of the steel and smelting methods. Fourth, the ingredients must meet the process requirements.