780MPa-level ultrahigh-strength Fe-Mn-Al-C lightweight cast steel and preparation method thereof

Abstract

The invention provides 780MPa-level ultrahigh-strength Fe-Mn-Al-C lightweight cast steel and a preparation method thereof. The low-density cast steel comprises, by mass, 0.80-1.30% of C, 15.00-20.00%of Mn, 3.50-8.00% of Al, 0.05-0.25% of Si, 0.5-1.5% of Cr, 0.01-0.06% of Cu, 0.30-0.80% of Mo, 0.05-0.20% of V, 0.01-0.10% of Nb, 0.005-0.025% of Ce, less than or equal to 0.01% of P, less than or equal to 0.01% of S, less than or equal to 0.01% of N, and the balance Fe and unavoidable impurities. Meanwhile, the weight percentage ratio of Mn to Al is no less than 2.5% and no more than 3.0%, and the sum of the weight percentages of Nb and V is no less than 0.10% and no more than 0.20%. The preparation process is simple and free of rolling, and the method can be used for manufacturing automobilestructure castings with complex shapes.

Description

technical field [0001] The invention relates to a Fe-Mn-Al-C low-density cast steel with a tensile strength of 780MPa and a preparation method thereof, belonging to the field of metal materials and metallurgy. Background technique [0002] With the current increasingly stringent emission regulations and the mandatory demand for fuel economy, lightweight itself is an inevitable trend in the history of the development of the automobile industry. The lightweight of the car is to reduce the curb weight 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. For every reduction of 100 kg in vehicle curb weight, fuel consumption per 100 kilometers can be reduced by 0.3-0.6 liters. Due to the needs of environmental protection and energy saving, the lightweight of automobiles has become the trend of the development of automobiles in the ...

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Problems solved by technology

[0004] In the existing production technology, CN104928569A discloses a 800MPa grade high ductility light steel and its preparation method. The production process of the method includes multiple processes such as melting, hot rolling, pickling, cold rolling, continuous annealing, etc. The process is complex, the equipment is expensive, and its products cannot be used to produce auto parts with complex shapes or complex inner cavities, so it is not suitable for its promotion and application

CN106399858A discloses a high-strength Fe-Mn-Al-C series low-density cast steel and its preparation method. It has high Mn and Ti content and high tensile strength, but its plasticity is poor and it is prone to brittle fracture , and add a lot of precious elements, the cost is high and it is not suitable for large-scale promotion and application, and the scope of application is limited

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