700 MPa level automobile beam steel belt and preparation method thereof

Abstract

The invention provides a 700 MPa level automobile beam steel belt and a preparation method thereof. The beam steel belt comprises the following chemical components in percentages by weight: 0.06% to 0.08% of C, 0.10% to 0.20% of Si, 1.60% to 1.80% of Mn, 0 to 0.017% of P, 0 to 0.002% of S, 0.020% to 0.050% of Alt, 0.065% to 0.085% of Ti, 0.045% to 0.055% of Nb and the balance of Fe and unavoidableimpurities. The 700 MPa level automobile beam steel belt provided by the invention has an excellent mechanical property, particularly low-temperature toughness, simultaneously has good welding performance, and can be used for automobile structural parts such as automobile cross beams and longitudinal beams with good forming processability and high strength requirement.

Description

technical field [0001] The invention relates to the technical field of high-strength steel production, especially with high strength, excellent plasticity and welding performance, and good low-temperature impact performance, and is mainly used for automobile structures such as automobile beams and longitudinal beams that require good forming and processing performance and high strength requirements. pieces. Background technique [0002] Due to environmental pressure and shortage of resources, lightweight has become an important issue for the sustainable development of the automobile industry, and lightweight has been proven to be the key technical route of "energy saving and emission reduction" for automobiles. The lightweight of the car is to reduce the equipment quality of the car as much as possible under the premise of ensuring the strength and safety performance of the car, so as to improve the power of the car, reduce fuel consumption, and reduce exhaust pollution. Ex...

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Problems solved by technology

[0004] Tang Jiayue et al. (Tang Jiayue et al., Trial production of 700MPa-grade high-strength automobile side beam steel, Hebei Metallurgy, No. 9, 2016) adopted the Nb, V, Ti composite microalloying process, through molten iron desulfurization, converter vanadium extraction, converter smelting, LF furnace refining, slab protection casting and other processes, the 700MPa grade automobile frame steel produced can meet the requirements of users, but the chemical composition contains a lot of alloys, adding alloy element V, the production cost is high, and the benefit per ton of steel is reduced.

Zhao Peilin et al. (Zhao Peilin et al., Research and Development of 700MPa High-strength Automobile Beam Steel, Laigang Science and Technology, No. 3, June 2010) added microalloying elements Nb and Ti to the 1500mm hot rolling production line to promote carbonitride Precipitation increases the effect of precipitation strengthening and improves the strength of the material. However, the tensile strength of the steel plates produced in the design and trial production is less than 750MPa. Due to the low strength, the thickness reduction of the designed girder is limited.

Wang Qi et al. (Wang Qi et al., Development of C700L high-strength automobile beam steel, Hebei Metallurgy, No. 8, 2014) adopted the Nb, V, Ti composite microalloying process, and passed the controlled rolling and controlled cooling process in the 1780mm hot rolling production line. , so that the various properties of the material can meet the user's requirements, but the -20°C low temperature impact toughness of the designed and trial-produced steel plate is low

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