High-strength plastic accumulation TRIP (Transformation-Induced Plasticity) steel plate and preparation method thereof

Abstract

The invention discloses a high-strength plastic accumulation TRIP (Transformation-Induced Plasticity) steel plate and a preparation method thereof, wherein the high-strength plastic accumulation TRIP steel plate consists of the following elements: 0.08%-0.5% of C, 0.4%-2.0% of Si, 3%-8% of Mn, smaller than or equal to 0.10% of P, smaller than or equal to 0.02% of S, 0.02%-4% of Al, smaller than or equal to 0.01% of N, 0-0.5% of Nb, 0-0.5% of V, 0-0.5% of Ti, 0-2% of Cr, 0-1% of Mo, and the balance of Fe and unavoidable impurities. In a microstructure, martensites account for 30%-90% by area occupation ratio, austenites account for 5%-30% by volume fraction, and the remaining is few ferrites and cementites. The hot rolling heating-up temperature is 1100-1250 DEG C, the holding time is more than or equal to 2 hours, the initial rolling temperature is higher than or equal to 1100 DEG C, the final rolling temperature is 850-950 DEG C, and the coiling temperature is lower than 720 DEG C; a hot rolled plate is 2-4mm in thickness; and the cover annealing is furnace heating for heat preservation at 550-750 DEG C for 1-20 hours and then furnace cooling.

Description

technical field [0001] The invention belongs to the field of steel manufacturing for automobiles, and relates to a high-strength plastic TRIP steel plate with a strong plastic product ≥ 30 GPa% and a preparation method thereof. Background technique [0002] With the continuous improvement of people's requirements for automobile environmental protection, safety and energy saving, the automobile industry has put forward higher requirements for automobile steel, which not only requires high strength of automobile steel, but also requires good elongation of automobile steel to meet Stamping requirements for auto parts. In order to meet the requirements of the rapid development of the automobile industry, major steel companies in the world have successively developed the first-generation advanced high-strength steel represented by DP and TRIP steel, the second-generation advanced high-strength steel represented by TWIP steel, and QP steel and high-strength steel. The third gener...

AI Technical Summary

Problems solved by technology

The disadvantage is that the strength and plasticity of DP steel and TRIP steel are about 20GPa%, which is difficult to meet the ever-increasing energy-saving, safety and environmental protection standards of the automobile industry.

The disadvantage is that the manganese content is high, between 15 and 24%, the cost is high, and the price is expensive

[0006] As one of the third-generation advanced high-strength steels, QP steel has good strength and plasticity. The disadvantage is that the process is complex and requires a special continuous annealing line to achieve its process requirements, so the cost is high and the performance stability is poor.

The disadvantages are (1) the Al content in the steel is high, within the range of 1-8%, continuous casting is difficult; (2) the annealing time of the steel plate is between 2-20 minutes, the annealing time is short, it is difficult to make Mn rich purpose of set

[0009] Patent CN 102321854A provides a low-carbon high-manganese TRIP steel and its production method. Its advantage is that the tensile strength reaches 1000~1500MPa. The disadvantage is that a large amount of alloy is added to the steel, resulting in high cost

At the same time, the hot-rolling coiling temperature is 580 degrees, and the coiling temperature is low, which makes cold rolling difficult

Images