The automotive industry often uses high-strength wear-resistant plates to reduce the weight of cars and improve safety, but this will also cause a series of problems such as cracking and unstable welding. Therefore, when using wear-resistant plates, wear-resistant plates with different functions should be used according to the different structures used.
According to international research on ultra-light steel cars, steel plates with a yield strength in the range of 210-550n/mm2 are called high-strength steel plates, and steel plates with a yield strength greater than 550n/mm2 are called ultra-high-strength steel plates. According to different strengthening mechanisms, high-strength steel plates are divided into ordinary high-strength steel plates and advanced high-strength steel plates.
Its Among them, ordinary high-strength steel plates mainly include high-strength IF steel, bake-hardened steel, phosphorus-containing steel, isotropic steel, carbon-manganese steel and high-strength low-alloy steel; advanced high-strength steel plates mainly include dual-phase steel, complex-phase steel, phase-transformation-induced plasticity steel, bainite steel and martensite steel, etc. As the strength of various types of steel increases, the plasticity decreases significantly. Although the plasticity decreases with the increase of strength, the degree of plasticity decrease of various steels is different due to different strengthening mechanisms. Steels strengthened by phase organization have the comprehensive excellent characteristics of high strength and high plasticity, such as TO steel and D0 steel. Since most automobile body parts are formed by stamping, plastic parts are cold-rolled, and the important properties of automobile steel plates are Therefore, steels with excellent comprehensive properties of strength and plasticity have become the development trend of high-strength steel plates.
Research shows that various types of high-strength steel plates have different uses due to their inherent characteristics. For example, bake-hardened steel plates are softer before stamping, have good shape stability, and have high dent resistance after baking. They are particularly suitable for stamping automobile exterior covers. Dual-phase steel and phase-change induced plasticity steel have high strength, high collision absorption energy, and high fatigue resistance, and are suitable for stamping structural parts and safety parts.
The stress conditions of steel used in high-rise buildings are complex, and it is required to have high safety and reliability, long service life, and be able to withstand the damage of a certain earthquake intensity. This determines that the steel plates used in high-rise building structures are required to have certain special properties, mainly the following points:
(1) It must be able to withstand the damage of a certain earthquake force and be earthquake-proof and earthquake-resistant. For this reason, the steel plate must not only have sufficient tensile strength and yield strength, but also have a low yield strength ratio. The low yield strength ratio can make the material have good cold deformation ability and high plastic deformation work, absorb more earthquake energy, and improve the earthquake resistance of the building.
(2) It must have good welding performance, so that no preheating is required before welding and no heat treatment is required after welding, so as to facilitate on-site welding, thereby reducing labor intensity and improving labor efficiency
(3) It must have high plasticity and toughness so that the steel plate has good mechanical properties.
