Ordinary Scrap Steel
Ordinary scrap steel is one of the main sources of metal in converter steelmaking. It reduces the carbon content of molten iron and acts as a coolant. Because the temperature of molten iron is very high during converter steelmaking, adding ordinary scrap steel can regulate the temperature of the molten pool and prevent it from overheating. For example, in smelting ordinary carbon steel, adding an appropriate amount of ordinary scrap steel makes the composition and temperature of the molten steel easier to control, thus producing qualified molten steel.
Alloy Scrap Steel
Alloy scrap steel is a key raw material for alloy steel production. In electric arc furnace steelmaking, it can replenish alloying elements in molten steel. Taking stainless steel production as an example, recycled stainless steel scrap contains alloying elements such as chromium and nickel. During remelting, these elements can be reintegrated into the molten steel, precisely adjusting the composition of the alloy steel, reducing the amount of new alloys added, lowering production costs, and ensuring the special properties of the steel, such as corrosion resistance and high-temperature resistance.
Heavy Scrap Steel
Heavy scrap steel, due to its larger size, melts relatively slowly during the steelmaking process. However, its higher density provides a stable supply of molten metal for the steelmaking process. For example, in electric arc furnace steelmaking, the gradual melting of heavy scrap helps maintain a stable molten steel level in the furnace, making the chemical reactions and energy transfer during the steelmaking process more stable. Moreover, its composition is relatively well-defined, which is beneficial for precise control of the final steel composition.
Medium Scrap
Medium scrap melts at a moderate rate and can be relatively evenly integrated into the molten steel during the steelmaking process. It can fill the gaps between heavy and light scrap, making the furnace charge mix more rational. For example, in the charging process of converter steelmaking, the addition of medium scrap can make the material distribution in the furnace more uniform, improve the efficiency of oxygen blowing, and promote the homogenization of the molten steel composition.
Light Scrap
Light scrap melts quickly due to its small size and thinness. It can quickly form a molten pool at the beginning of steelmaking, helping to increase the furnace temperature. However, because of its large surface area, it is prone to oxidation, so the charging time and method need to be carefully controlled. For example, in induction furnace steelmaking, adding a portion of light scrap steel first can quickly establish the melting environment, and then adding other types of scrap steel together to complete the steelmaking process.
Industrial Scrap Steel
Industrial scrap steel has a relatively stable composition and fewer impurities, making it a high-quality raw material for producing high-quality steel. During the steelmaking process, it can be recycled according to precise formulas and process requirements to produce high-quality steel. For example, industrial scrap steel recycled from auto parts processing plants has a relatively clear material and composition, and after simple processing, it can be used to produce steel of the same type or higher quality requirements.
Social Scrap Steel
Although social scrap steel has a complex composition and more impurities, it can be used as a supplementary raw material for steelmaking after pretreatment. Its utilization contributes to resource recycling and environmental protection. During steelmaking, social scrap steel can be mixed with other scrap steel, and through reasonable batching and smelting processes, impurities can be removed, transforming it into valuable molten steel. For example, social scrap steel such as discarded appliance casings, after pretreatment such as crushing and sorting, can be added to the electric furnace steelmaking process.