Special steel is usually considered an important indicator of whether a country can become a steel powerhouse. It is the main type of steel used in most industries of the national economy, such as machinery, automobiles, military industry, chemical industry, household appliances, ships, transportation, railways, and emerging industries.

1. Definition: Special steel refers to steel products that have special physical, chemical properties or special uses due to their special composition, structure, and production process. It belongs to a branch of the traditional steel industry and corresponds to ordinary steel, but their uses are significantly different. In the downstream demand of ordinary steel, infrastructure construction and real estate account for more than half of the total, while special steel products are mainly used in automobiles, machinery manufacturing, petrochemicals, aerospace and military industries.

2. Classification: According to usage, special steel can be divided into eight categories: high-quality carbon structural steel, alloy structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, bearing steel, spring steel (carbon spring steel and alloy spring steel), and stainless steel (heat and acid resistant). Except for high-quality carbon structural steel, carbon tool steel, and carbon spring steel, all others are alloy steel, with alloy steel accounting for about 70% of special steel.