Scrap steel refers to the steel waste generated during the production process of steel mills, such as trimmings, offcuts, and discarded equipment or components containing steel. Scrap steel refers to materials that contain steel, while scrap iron refers to materials that contain pig iron. Together, they are commonly referred to as scrap steel.
The annual global production of scrap steel is approximately 300-400 million tons, accounting for about 45-50% of the total steel production. Around 85-90% of scrap steel is used as raw material in steelmaking, while 10-15% is utilized in casting, iron refining, and the production of recycled steel materials.
The scrap steel generated during the production process of steel mills is referred to as “home scrap,” “in-house scrap,” or “recycled scrap.” It typically has a carbon content of less than 2.0% and sulfur and phosphorus content not exceeding 0.05%. Scrap steel comes in various shapes depending on its origin, and its properties are generally similar to the base material from which it was produced. However, factors such as aging effectiveness and fatigue can affect its performance, leading to some reduction in properties. Home scrap from regular steel mills accounts for approximately 15-25% of the steel production, while special steel mills may reach 30-50%.
Scrap steel is primarily generated in steelmaking workshops, steel casting workshops, and cold and hot processing workshops. With advancements in steel production technology, the yield of steel products has increased, leading to a downward trend in the proportion of in-house scrap to steel production. Scrap steel generated from steel products and manufacturing processes accounts for around 20-25% of the total scrap steel volume and mainly includes cut-offs, trimmings, chips, and corner materials. Various types of discarded equipment, steel structural components, decommissioned locomotives, vehicles, rails, automobiles, ships, tools, and appliances also contribute to a significant portion of “depreciation scrap.” In developed industrial countries, it accounts for approximately 25-30% of the total scrap steel volume and represents 1-1.5% of the total steel material input. Currently, China generates around 3 million tons of depreciation scrap steel per year. Scrap steel from household items like cans, furniture, and utensils is referred to as “social scrap” or “garbage scrap” and can sometimes amount to 1% of the steel material input. Additionally, there are sources of scrap steel, such as recovered steel from slag, accumulated scrap steel pieces, and salvaged sunken ships, making the origins of scrap steel quite complex.