A kind of high plasticity high tenacity super high strength steel plate and its production method

Abstract

The invention discloses a high-plasticity, high-toughness, ultra-high-strength steel plate and a manufacturing method thereof. The chemical composition of the high-strength steel plate is calculated by weight percentage, C: 0.14-0.18%, Si: 0.10-0.30%, Mn: 0.80-1.30%, P : ≤0.015%, S: ≤0.005%, Nb: 0.010~0.050%, Ti: 0.006~0.020%, V: 0.020~0.060%, Cr: 0.30~0.60%, Mo: 0.20~0.80%, the balance is Fe and unavoidable impurities. Manufacturing method: Smelting in a converter. Through the TMCP process, followed by quenching and tempering treatment. The microstructure of the high ductility, high toughness and ultra-high strength steel plate obtained is tempered sorbite, the lamellar spacing is fine, and the original austenite grains are uniform and fine. It has the characteristics of stable production process, strong operability, low cost and high performance.

Description

technical field [0001] The invention relates to a high-strength steel plate, in particular to a high-plasticity high-toughness ultra-high-strength steel plate and a production method thereof. Background technique [0002] With the rapid development of the equipment manufacturing industry, the market demand for construction machinery steel is increasing, and the development prospect is broad. Low-alloy high-plasticity high-toughness ultra-high-strength steel can be widely used in equipment manufacturing industries such as cranes, motor vehicle chassis, and bulldozer accessories due to its advantages such as ultra-high strength, good processing and forming, high impact toughness, and good weldability. High strength, good manufacturability components, and can reduce cost, reduce mass and increase payload. It is generally believed internationally that structural steel with a yield strength ≥ 840MPa can be called ultra-high-strength structural steel. Because this type of steel ...

AI Technical Summary

Problems solved by technology

[0008] manufacturing method, the production method is also to heat the steel billet, roll in the austenite recrystallization zone and non-recrystallization zone, and cool at a rate greater than 5°C / s Cooled below the Ms point, the yield strength is 960MPa, but its -20°C V-type impact absorption energy is only 35-55J

It can be seen that due to the high-strength steel obtained by direct TMCP rolling, the strength and toughness of the steel have not reached a good match

[0009] Chinese patent 200810080072.6 discloses a high-plasticity and high-toughness ultra-high-strength steel plate. The elements are complex, and there are many precious alloys, which require thermal straightening, and the straightening temperature is relatively high, between 500-600°C

It shows that although after quenching and tempering treatment, the residual stress in the steel plate is relatively large, which leads to the problem of plate shape, and also increases the process and cost

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