High-impact-toughness automotive frame steel belt and production method thereof

Abstract

The invention relates to a high-impact-toughness automotive frame steel strip and a production method thereof. The high-impact-toughness automotive frame steel strip comprises the following chemical components in percentage by weight of 0.03%-0.08% of C, 0.10%-0.20% of Si, 1.50%-1.80% of Mn, less than or equal to 0.017% of P, less than or equal to 0.005% of S, 0.010%-0.050% of Als, 0.020%-0.040% of Ti, 0.020%-0.050% of Nb, 0.30%-0.60% of Cr, less than or equal to 0.0055% of N, and the balance Fe and other ineveitable residual elements. A sectional cooling process is selected in cooling after rolling in a rolling process, and a uniform and fine ferrite and bainite double-phase structure is obtained by accurately controlling the temperature, the cooling speed and the air cooling time, so that steel has good low-temperature impact toughness while having high strength.

Description

technical field [0001] The invention belongs to the technical field of steel strips, and in particular relates to a high-impact-toughness automobile beam steel strip and a production method thereof. Background technique [0002] Automobile frame steel is mainly used for load-bearing components such as longitudinal beams, beams, lining beams and connecting plates of light trucks, heavy truck tractors, trailers, and dump trucks. The impact of complex stress under various working conditions such as braking, driving on potholes and bumpy roads, puts forward higher requirements on the low-temperature impact performance and fatigue resistance of girder steel. At present, under the background of increasingly strict national environmental protection policies, the lightweight design of automobiles has gradually become the mainstream. The advantages of high-strength beam steels above 900 MPa in weight reduction and energy saving The design of adding expensive alloys such as Mo and V ...

AI Technical Summary

Problems solved by technology

The patent adopts conventional technology to produce girder steel, which has good plasticity and extensibility. The disadvantage is that the tensile strength of the material is only 610-710MPa, which is not suitable for making large-load heavy truck load-bearing beams, and the product application range is limited.

The design cost of the alloy of this invention is low, and it can be rolled and produced on a low-end double-stand reversing steckel rolling mill. The disadvantage is that the content of C and Si is relatively high, and the welding performance and surface quality of the material are affected. The uniformity of structure and performance is not easy to guarantee. The strength of the girder steel produced according to this invention is about 510MPa, which is only suitable for use on light trucks with small tonnage. The limited strength cannot meet the current design requirements for lightweight and weight reduction of automobiles

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