High-strength steel is a new type of structural material compared to traditional low-alloy structural steel. Its main characteristics are high strength, toughness, wear resistance, and corrosion resistance. The use of high-strength steel can reduce structural weight, increase structural stiffness and strength, and enhance safety and reliability. The material composition and related standards of high-strength steel vary, but generally require low carbon content, high alloy element content, and high hardness after quenching. High-strength steel is commonly used in bridges, automobiles, aerospace, forging machinery, and other fields.
High-strength steel refers to steel with a tensile strength above 860 megapascals (MPa) and a yield strength of approximately 480 MPa. To achieve high strength, the carbon content must be low, generally below 0.2%, sometimes as low as 0.1%.
Top 7 Main Requirements High-Strength Automotive Steel
High-strength steel has excellent comprehensive mechanical properties and is mainly used to manufacture automotive parts that require high strength and good impact resistance, such as gearbox housings, axles, and engine crankshafts. The main requirements for high-strength automotive steel are:
- High strength: Yield strength ≥ 700 MPa, tensile strength ≥ 900 MPa.
- Good toughness: Low-temperature impact toughness should be ≥ 15J/cm^2.
- Good weldability: Good welding performance, with maximum welding stress not less than 70% of the yield point.
- Good formability: Good forming performance, with elongation at fracture greater than 20%.
- Good carburizing performance: The carbon content of the surface layer should reach 0.8%~1.2%, and the carburizing layer depth should be greater than 2mm.
- Good machinability: Good machinability, with cutting speed not less than 80m/min.
- Good corrosion resistance.
Ultra-high-strength steel is a type of high-strength steel with strength far exceeding that of traditional structural steel and high-strength steel, and it has super strong plasticity and toughness, capable of withstanding large tensile, bending, and compressive stresses. Ultra-high-strength steel is generally divided into four types: high hardness, high plasticity, high wear resistance, and high alloy. Its main application fields are aerospace, energy, petroleum, chemical, and shipbuilding industries.
Ultra-high-strength steel refers to steel with a yield strength and tensile strength exceeding 1200 megapascals (MPa) and 1400 megapascals (MPa), respectively. It is mainly used to manufacture structural components subjected to high stress, generally with sufficient toughness, high specific strength and yield strength ratio, as well as good weldability and formability.
Hot-formed steel is a type of steel that changes the structure and properties of steel through heating and deformation during steel processing. It is achieved by plastic deformation of steel at high temperatures to change its shape and structure, thereby obtaining the desired mechanical properties. Hot-formed steel is usually processed at high temperatures, generally above the recrystallization temperature of the steel. During hot processing, the grains of the steel will rearrange, and the internal structure and grain boundaries will be improved, thereby improving the comprehensive performance of the steel. Hot-formed steel usually has high strength, toughness, and wear resistance advantages, and its cost is relatively low. The manufacturing process of hot-formed steel is relatively simple, without multiple heat treatments, and can produce large quantities of high-strength tough steel. Hot-formed steel is mainly used in automotive, machinery, and engineering machinery fields.
In summary, although high-strength steel, ultra-high-strength steel, and hot-formed steel all have the characteristics of high strength, they differ in terms of material composition, processing technology, and application scope. When selecting materials, suitable types of steel should be chosen according to actual requirements.