Ultrahigh strength TRIP steel with pressure intensity being 1.5GPa or higher and preparation method thereof

Abstract

The invention discloses ultrahigh strength TRIP steel with the pressure intensity being 1.5GPa or higher and a preparation method thereof, and belongs to the technical field of hot-rolled steel plates with the high product of strength and ductility. The ultrahigh strength TRIP steel comprises the chemical components of 0.1-0.25wt.% of C, 5-10% wt.% of Mn, 1-3wt.% of Si, 0-0.2wt.% of P, 0-0.005wt.% of S, and the balance Fe and inevitable impurities. The preparation method comprises the steps of smelting, casting, forging, rolling and annealing; in the rolling process, quenching is conducted after multiple passes of hot rolling; the rolling starting temperature is 1100-1250 DEG C; the finish rolling temperature is 850-950 DEG C; a TMCP technology is applied to quenching; and in the annealing process, the temperature is increased to 600-750 DEG C in the two-phase region, heat preservation is carried out for 2-5 h, and air cooling is conducted till the temperature is equal to the room temperature. A prepared ultrahigh strength TRIP steel plate has the ultrahigh strength mechanical property characteristic, the tensile strength is higher than or equal to 1500MPa, the yield strength is higher than or equal to 800MPa, the percentage elongation is larger than or equal to 20%, and the product of strength and ductility is higher than or equal to 30GPa.%.

Description

technical field [0001] In particular, the invention belongs to the technical field of ultra-high-strength and high-plasticity steel, and in particular relates to an ultra-high-strength TRIP steel above 1.5 GPa level and a preparation method thereof. Background technique [0002] For automobile manufacturing, among many measures to reduce fuel consumption, energy saving and emission reduction, reducing body weight and improving safety are the most important development directions. Studies have shown that every 10% reduction in body weight can save fuel by 3% to 7%. Therefore, the application of automobile lightweight technology has become one of the key technologies for major automobile manufacturers to improve their competitiveness. In order to achieve the goals of energy saving, emission reduction and safety improvement, the concept of advanced high strength steel (AHSS) came into being. After years of research and development, advanced high strength steel has developed to...

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Problems solved by technology

[0007] Chinese invention patent application publication specification CN102912219A The invention discloses a high-strength plastic product TRIP steel plate, C: 0.08%-0.5%, Si: 0.4%-2.0%, Mn: 3%-8%, P: ≤0.10%, S: ≤0.02%, Al: 0.02%~4%, N: ≤0.01%, Nb: 0~0.5%, V: 0~0.5%, Ti: 0~0.5%, Cr: 0~2%, Mo: 0~ 1%, and the rest is composed of Fe and unavoidable impurities; the process annealing takes a long time, increases production costs, wastes energy, and has low strength

[0008] The disadvantage of the TRIP steel in the prior art is that it has low strength-plastic product and low tensile strength, which cannot meet the demand of the modern automobile industry for higher strength of automobile steel, and the addition of a large amount of alloying elements increases the cost. (such as Ni, Nb, Ti, etc.) also increases the difficulty of manufacturing

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