Multipurpose all-austenite low-density steel and preparation method thereof

Abstract

The invention relates to a multipurpose all-austenite low-density steel and a preparation method thereof, and belongs to the technical field of metal materials and preparation thereof. The steel comprises the following chemical components of, by weight, 0.40%-0.90% of C, 15.0%-25.0% of Mn, 3.0%-6.0% of Al, 0.3%-0.80% of Mo, 0.3%-0.90% of V, 0.01%-0.04% of Ti, 0.02%-0.10% of Nb, less than or equalto 0.3% of Si, less than or equal to 0.03% of P, less than or equal to 0.002% of S, less than or equal to 0.006% N (60 ppm), and the balance Fe and inevitable impurities; the density is 7.0-7.4 g / cm<3>, and the structure type is a total austenite + nano-scale VC and an MoC precipitation phase; and the composition system is characterized in that uniform and stable all-austenite steady-state structure can be obtained through casting and controlled rolling and controlled cooling technologies. The steel and the method are suitable for various fields of automobiles, buildings, mechanical structuresand the like.

Description

technical field [0001] The invention belongs to the technical field of metal materials and their preparation, in particular to a multi-purpose fully austenitic low-density steel and a preparation method thereof. Background technique [0002] Reducing energy consumption, reducing environmental pollution and saving limited resources is a very important and urgent problem that people are facing today. Reducing the weight of automobiles is one of the important measures to improve the fuel economy and save energy consumption of automobiles. At present, domestic and foreign development and research on automobile lightweight projects are mostly developing high-strength or ultra-high-strength steel plates, and reducing the weight of automobiles by reducing the thickness of steel plates used. The application of high-strength steel and advanced high-strength steel to replace traditional low-strength grade steel can improve the specific strength (ratio of strength to density) of steel ...

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Problems solved by technology

CN104928569A and CN106011652B disclose a kind of 800MPa level high ductility light steel and preparation method thereof, this material is the low-density steel of medium carbon, medium manganese, its strength only has 800MPa, and the production procedure of this method is comparatively complicated

CN106399858A discloses a high-strength Fe-Mn-Al-C low-density cast steel and its preparation method. Although the tensile strength reaches 1400MPa level, its plasticity is poor. Due to the addition of a large amount of Mn, Ti, Al, Cr, Too high cost is not suitable for industrial production and popularization and application

CN108642403A discloses a kind of low-density steel of 780MPa grade, because C content is too high and there is certain problem in the ratio design of alloy composition, makes intensity low, and can't obtain full austenite structure

CN104674109A and CN103667883B disclose a low-density steel with ultra-high Al, whose density can be reduced to 6.65-6.80g / cm 3 , although the strong plastic product can reach about 40GPa·%, but the strength can only reach 900MPa level, and it is still α+γ duplex structure

CN102690938B discloses an Al-containing steel with ultra-low C and ultra-high Mn. Through the manufacturing method of intermediate frequency induction furnace and electroslag remelting, a fully austenitic low-density steel is obtained, although the strong plastic product can reach 52.8GPa·% , but since the Al content is only 1.85%, the predicted density of the steel reaches 7.5 g / cm 3 , and the strength is only 700MPa, so it is basically impossible to reduce the weight of existing vehicles, construction and engineering machinery related load-bearing structures

[0007] It can be seen that the main composition system currently used is Fe-Mn-Al-C system, the tensile strength of the material can only reach 1200MPa, and the density is 7.0g / cm 3 , but the strong plasticity is not enough, it is difficult to reach more than 35GPa·%

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