The steel industry is one of the important strategic industries of a country. The steel industry is mainly an industrial sector engaged in industrial production activities such as the mining and selection of ferrous metal minerals and the smelting and processing of ferrous metals. Specifically, it can be divided into metal mineral mining and selection, ironmaking, steelmaking, steel rolling, processing of steel products, and ferroalloy smelting, etc. According to the standard of "National Economic Industry Classification" (GB/T4754-2011), the steel industry belongs to the secondary industry, including the mining and selection of ferrous metals and other ferrous metal mining and selection industries. The ferrous metal smelting and rolling processing industry mainly includes ironmaking, steelmaking, ferrous metal casting, steel rolling processing and ferroalloy smelting.
According to the relevant provisions of the "Statistical Index System for China's Steel Industry Production" (2003), the main products of the steel industry are mainly classified into four categories: pig iron, crude steel, steel products and ferroalloys. Among them, pig iron refers to crude iron directly produced in blast furnaces. The carbon content of industrial pig iron is generally between 2.11% and 4.3%, and it also contains elements such as C, Si, Mn, S, and P. Crude steel refers to steel that has completed the smelting process but has not undergone plastic processing. According to the smelting method, it can be classified into three major categories: electric furnace steel, converter steel, and other steel. Steel mainly refers to the final steel that the national steel industry can provide to society, which is divided into carbon structural steel, alloy structural steel, stainless steel, etc. The definition of the steel industry in this article is based on the definition of the steel industry by the National Development and Reform Commission of The State Council: The scope of the steel industry includes the mining and selection of iron ore, manganese ore and chromium ore, sintering, smelting, ferroalloys, carbon products, refractory materials, ironmaking, steelmaking, steel rolling, metal products and other related processes.
The steel industry is a typical midstream industry. Its upstream involves raw materials and auxiliary materials, including iron ore raw materials, coking coal, raw coal, etc., as well as recycled scrap steel. Its downstream mainly serves industries such as construction, machinery, and real estate. The steel industry is a demand-oriented industry. The transmission effect of the entire industrial chain is bottom-up, that is, the downstream demand affects the steel output and then affects the raw material demand of the upstream.