Light and high-performance twin crystal inducing plasticity steel and preparation method thereof

The invention provides light and high-performance twin crystal inducing plasticity steel, which comprises the following chemical compositions: 0.30 to 0.80 percent of C, less than or equal to 0.4 percent of Si, 15 to 25 percent of Mn, less than or equal to 0.05 percent of Al, 0.04 to 0.16 percent of P, 0.10 to 0.30 percent of Re, 0.01 to 0.02 percent of N and the balance of Fe. A preparation method comprises that: 1) vacuum melting is adopted and the tapping temperature is between 1,450 and 1,550DEG C; 2) a cast ingot is subjected to hot rolling, the initial temperature is between 1,150 and 700DEG C, the finishing temperature is more than or equal to 550 DEG C, and the cold rolled reduction ratio is between 40 and 80 percent; and 3) the annealing is performed at a temperature of between 600 and 1,000DEG C, and the steel is kept at a constant temperature for 0.5 to 20 minutes and then cooled to room temperature in a rate of 5 to 20 DEG C/s. Through composition design, the preparation method controls the casting, directly performs hot rolling and cold rolling for forming, and combines a heat treatment process to prepare the high-performance TWIP steel of which the strength and toughness balance is more than 40,000MPa percent. The light and high-performance twin crystal inducing plasticity steel is not added with silicon, aluminum and precious alloys, has low cost and high purity,and can avoid the defects of hot rolled billets; and the TWIP steel with different strength and plasticity can be prepared through different heat treatment systems, and the effective utilization of energy and resource can be achieved.