Steel with 1,300MPa-level tensile strength for automobile safety piece and production method thereof

Abstract

The invention relates to steel with 1,300MPa-level tensile strength for an automobile safety piece and a production method thereof. The steel comprises the following components in percentage by weight: 0.12 to 0.22 percent of C, 0.10 to 0.40 percent of Si, 1.00 to 1.60 percent of Mn, 0.10 to 0.45 percent of Cr, 0.01 to 0.10 percent of Ti, 0.0005 to 0.005 percent of B, 0.01 to 0.06 percent of Als,less than or equal to 0.025 percent of P, less than or equal to 0.010 percent of S and less than or equal to 0.008 percent of N. The production method comprises the following steps of: smelting by using a converter; alloying; performing vacuum treatment and component fine turning; continuously casting; heating a casting blank to the temperature of between 1,220 and 1,280 DEG C; performing rough rolling; performing fine rolling; performing laminar flow cooling; reeling; performing acid-washing; performing cold rolling; annealing; smoothing; finishing; cutting; heating and austenitizing under the protective atmosphere of nitrogen; forming a mold; quenching; tempering; and taking a member out for later use. The steel has ultrahigh intensity, meets the requirements of an automobile industry on the intensity and the rigidity of the safety piece of a vehicle body, can be complicatedly deformed without resilience, has high dimensional accuracy of parts and can be industrially produced on common large production equipment.

Description

technical field [0001] The invention relates to steel for automobiles and a production method thereof, in particular to steel for automotive safety parts with a tensile strength of 1300 MPa and a production method thereof. Background technique [0002] With the development of the automobile industry towards energy saving, environmental protection and safety, ordinary high-strength steel can no longer fully meet the needs of automobile production. Therefore, the development and application of ultra-high-strength steel has become the focus of attention of the steel industry and the automobile industry in recent years. Tests have proved that the use of ultra-high-strength steel can reduce the weight of the car while reducing friction noise, reducing emissions, and improving the quality of the car body. [0003] However, as the strength of the steel plate continues to increase, its elongation decreases significantly, and the formability also decreases greatly. Cracks and springb...

AI Technical Summary

Problems solved by technology

[0008] However, the existing 1300MPa ultra-high-strength cold-formed martensitic steel has disadvantages: difficult forming, severe springback after forming, poor dimensional accuracy of parts, low pass rate, and cannot meet user requirements; in addition, it is not suitable for industrial production. The requirements for equipment are relatively high, and the existing production equipment cannot complete industrial production. Only professional high-strength steel production lines can be used to complete industrial production, and large-tonnage blanking equipment must be used in the blanking process of automobile factories in the later stage.

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