Low-density ultrahigh-strength steel and preparation method thereof

Abstract

The invention relates to low-density ultrahigh-strength steel and a preparation method thereof, and belongs to the field of metal materials. The steel comprises the following chemical components in percentage by mass: 0.6 to 1.6 percent of C, 5 to 10 percent of Al, 15 to 30 percent of Mn, 0.01 to 0.2 percent of Nb, 0.1 to 3 percent of Mo, less than or equal to 5 percent of Cr, less than or equal to 0.5 percent of Ti, less than or equal to 2 percent of Si, less than or equal to 0.6 percent of B, and the balance of Fe and unavoidable impurity elements. According to the low-density ultrahigh-strength steel and the preparation method thereof, a NbMoC phase which is finely dispersed precipitates by compounding and adding the Nb and the Mo; precipitation is strengthened by cooperating with a kappa-carbide; the tensile strength reaches over 1,350 MPa, the elongation reaches over 10 percent and the density is 6.8 to 7.0 g / cm<3>; the low-density ultrahigh-strength steel is low in cost, is suitable for light weight of traffic transportation tools, such as vehicles and airplanes, and meets the development concept of energy conservation and emission reduction.

Description

technical field [0001] The invention relates to a low-density ultra-high-strength steel and a preparation method thereof, belonging to the field of metal materials. Background technique [0002] In order to save energy, improve fuel economy and reduce CO 2 Lightweight has become an important development trend of various means of transportation. One way of thinking is to reduce the amount of steel required by improving the mechanical properties of steel such as strength and plasticity, so as to achieve the purpose of weight reduction. Another way of thinking is to reduce the density of steel by adding alloy elements such as Al, and at the same time ensure the mechanical properties of steel by optimizing the composition and controlling the treatment process, so as to obtain steel with both low density and high strength. Studies have shown that for every 1% Al added, the density of steel decreases by 0.101g / cm 3 , can reduce weight by about 1.3%; for every 1% of C added, the...

AI Technical Summary

Problems solved by technology

A low-density, high-plasticity NiAl-enhanced ultra-high-strength steel has been reported, mainly relying on the addition of Ni to form NiAl to increase the tensile strength of the steel. Ni element, resulting in greatly increased cost