Ultrahigh-strength cold-rolled steel plate and manufacturing method thereof

Abstract

The invention discloses an ultrahigh-strength cold-rolled steel plate and a manufacturing method thereof. The steel plate comprises the following components in percentage by mass: 0.05 to 0.08 percent of C, 0.10 to 0.40 percent of Si, 0.50 to 1.0 percent of Mn, 0.008 to 0.030 percent of P, less than or equal to 0.006 percent of S, 0.08 to 0.20 percent of Ni, 0.20 to 0.55 percent of Cu, 0.30 to 0.60 percent of Cr, 0.015 to 0.045 percent of Al, 0.06 to 0.13 percent of Ti and the balance of Fe and inevitable impurities. The manufacturing method comprises the following steps of: smelting, casting to form a plate blank, hot rolling, heating the plate blank at the temperature of more than 1,250 DEG C, performing finish rolling, starting rolling at the temperature of between 980 and 1,100 DEG C, stopping rolling at the temperature of between 880 and 950 DEG C, and coiling at the temperature of between 580 and 690 DEG C; and cold rolling in the screw-down rate of between 50 and 70 percent, and annealing at the temperature of between 690 and 800 DEG C in a continuous annealing machine set after cold rolling.

Description

technical field [0001] The invention belongs to the technical field of high-strength steel production, and in particular relates to an ultra-high-strength cold-rolled steel plate and a manufacturing method thereof. Background technique [0002] High-strength steel plates have attracted widespread attention in the industry because they can effectively reduce their own weight while ensuring strength. This type of steel is mainly used in the manufacture of high-speed train carriages, special containers, and automobiles, and plays an important role in increasing speed, increasing loading capacity, prolonging the service life of equipment, and reducing energy consumption costs. In the process of reducing the weight of the structure, designers are most worried about the decrease of stiffness. For ordinary high-strength steel, this problem is very prominent, because the steel plate with many rolling defects is easy to fail under the fatigue stress below the yield limit during the ...

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Problems solved by technology

[0004] Patent Publication No. CN 1386139A "Ultra-high-strength cold-rolled steel plate and its manufacturing method" patent, although the yield strength reaches more than 800MPa, but it needs to adopt rapid cooling continuous annealing equipment in the subsequent annealing process, which increases the manufacturing cost. cost

[0005] In the patent "TRIP steel plate for high-strength cold-rolled continuous annealing and its preparation method" (patent publication number CN 101363102A) published in 2009, although the yield strength is above 600MPa and has good elongation, it cannot meet Lightweight requirements of container, automobile and other industries

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