Steel plate and preparation method thereof

A steel plate and dual-phase steel technology, applied in the field of steel rolling, can solve the problems of high cost of dual-phase steel, achieve the effects of reducing the yield ratio, improving welding performance, and improving the distribution state

Active Publication Date: 2014-07-23
MAGANG (GROUP) HOLDING CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Judging from the patent situation, due to the addition of a large amount of precious metals such as Al and Mo, the cost of the produced dual-phase steel is relatively high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Chemical composition (mass percentage) of steel C: 0.08%, Mn: 1.56%, Si: 0.32%, Cr: 0.36%; the balance is iron and unavoidable impurities.

[0037] Its technological process is: smelting → continuous casting → hot rolling → pickling cold rolling → continuous annealing → finished product.

[0038] Process parameters: continuous annealing temperature is 780°C, slow cooling to 675°C and rapid cooling at a cooling rate of 30°C / s or above, and then overaging treatment at 290°C. The obtained cold-rolled dual-phase steel product has a yield strength of 287MPa, a tensile strength of 632MPa, an elongation of 24%, and an n value of 0.20.

Embodiment 2

[0040] Chemical composition (mass percentage) of steel C: 0.08%, Mn: 1.56%, Si: 0.32%, Cr: 0.36%; the balance is iron and unavoidable impurities.

[0041] Its technological process is: smelting → continuous casting → hot rolling → pickling cold rolling → continuous annealing → finished product.

[0042] Process parameters: continuous annealing temperature is 790°C, slow cooling to 700°C and rapid cooling at a cooling rate of 30°C / s or above, and then overaging treatment at 320°C. The obtained cold-rolled dual-phase steel product has a yield strength of 302MPa, a tensile strength of 620MPa, an elongation of 25%, and an n value of 0.18.

Embodiment 3

[0044] Chemical composition (mass percentage) of steel C: 0.08%, Mn: 1.56%, Si: 0.32%, Cr: 0.36%; the balance is iron and unavoidable impurities.

[0045] Its technological process is: smelting → continuous casting → hot rolling → pickling cold rolling → continuous annealing → finished product.

[0046] Process parameters: continuous annealing temperature is 785°C, slow cooling to 670°C and rapid cooling at a cooling rate of 30°C / s or above, and then overaging treatment at 290°C. The obtained cold-rolled dual-phase steel product has a yield strength of 284MPa, a tensile strength of 624MPa, an elongation of 27%, and an n value of 0.19.

[0047] The high-strength cold-rolled dual-phase steel plate for automobiles produced by adopting the chemical composition, technological process and specific methods and steps of the invention has a yield strength of 280MPa-310MPa, a tensile strength of 620MPa-650MPa, and an elongation of 23%-30%.

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Abstract

The invention relates to a steel plate and a preparation method thereof. The steel plate is a 600MPa grade cold-rolled dual-phase steel plate with low yield ratio and comprises the following components by mass percent: 0.05-0.09% of C, 0.2-0.5% of Si, 1.4-1.8% of Mn, 0.020-0.060% of Als, not more than 0.4% of Cr, not more than 0.02% of P, not more than 0.01% of S and the balance of Fe and inevitable impurities. The method comprises the following steps: smelting; continuous casting; hot rolling; acid pickling and cold rolling; continuous annealing; finished product obtaining. The steel plate has the beneficial effects that on the basis of a C-Mn system, the contents of C and alloying elements are reduced to improve the weldability of the material; the content of Si in the design is lower and meanwhile high hydrogen annealing is adopted in the continuous annealing production process, so that the produced dual-phase steel has better surface quality; on the basis, the distribution state of martensite can be improved by adding proper amount of Cr, thus being beneficial for giving play to the plasticity; meanwhile, the continuous annealing production speed can be properly reduced and then the shape of the steel plate can be improved by reducing the yield ratio of the dual-phase steel.

Description

technical field [0001] The invention belongs to the technical field of steel rolling, and relates to a steel plate and a preparation method thereof, in particular to the manufacture of a high-strength steel for automobile structural parts with excellent formability, in particular to a cold-rolled dual-phase steel plate with a tensile strength of 600MPa and low yield strength ratio and its Production method. Background technique [0002] In recent years, with the energy crisis, rising oil prices and the aggravation of the global warming effect, countries around the world have paid more attention to environmental problems caused by energy and carbon dioxide emissions, and have formulated and adopted various strict measures to control them. In the automotive field, addressing environmental issues and improving crash safety have become the most common keywords. According to statistics, for every 1% reduction in vehicle weight, the fuel can be reduced by 0.6-1.0%. On the other ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/04C22C33/04C21D8/02
Inventor 潘红波刘永刚张建张建平杨兴亮詹华舒宏富汪建威胡学文谷海容徐祥合张翠
Owner MAGANG (GROUP) HOLDING CO LTD
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