A kind of cold-rolled steel plate with a yield strength of 500mpa and its preparation method

A technology of yield strength and cold-rolled steel plate, which is applied in the field of cold-rolled steel plate with yield strength of 500MPa and its preparation, can solve the problems of increased movable dislocation density, difficulty in obtaining high yield ratio, and influence on precipitation strengthening effect, etc., to achieve reduction Difficult to control, low cost, guaranteed effect of precipitation strengthening

Active Publication Date: 2018-10-23
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existence of martensite leads to an increase in the density of mobile dislocations, thereby reducing the yield strength; in addition, the coiling temperature of about 600 ° C causes a large amount of microalloying elements to precipitate after hot rolling, which leads to the coarsening of precipitated particles during the subsequent continuous return process. Affect the effect of precipitation strengthening
The above two points cause the yield ratio of low alloy steel in this method to be lower than 0.8, making it difficult to obtain a high yield ratio

Method used

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  • A kind of cold-rolled steel plate with a yield strength of 500mpa and its preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] A cold-rolled steel plate with a yield strength of 500MPa, the composition and mass percentage are: C: 0.07%, Si: 0.03%, Mn: 0.9%, Nb: 0.02%, Ti: 0.04%, and the rest is Fe and unavoidable impurities element; its thickness is 1.5mm.

[0053] The preparation method of above-mentioned yield strength 500MPa grade cold-rolled steel plate, comprises the steps:

[0054] Step 1, smelting and forging:

[0055] According to the chemical composition of the 500MPa yield strength cold-rolled steel plate, the raw materials are selected and mixed, and then smelted into ingots; among them, the yield strength 500MPa grade cold-rolled steel plate has the composition and mass percentage of C: 0.07%, Si: 0.03%, Mn : 0.9%, Nb: 0.02%, Ti: 0.04%, the rest is Fe and unavoidable impurity elements; the ingot is forged into a 40mm thick slab;

[0056] Step 2, hot rolling:

[0057] (1) Heat the forged slab at 1240°C for 2.5 hours;

[0058] (2) Hot-rolling the slab after heat preservation, the ...

Embodiment 2

[0073] A cold-rolled steel plate with a yield strength of 500MPa, the composition and mass percentage are: C: 0.06%, Si: 0.1%, Mn: 0.95%, Nb: 0.03%, Ti: 0.03%, and the rest is Fe and unavoidable impurities element; its thickness is 1.2 mm.

[0074] The preparation method of above-mentioned yield strength 500MPa grade cold-rolled steel plate, comprises the steps:

[0075] Step 1, smelting and forging:

[0076] According to the chemical composition of the 500MPa yield strength cold-rolled steel plate, the raw materials are selected and blended, and then melted into ingots; among them, the yield strength 500MPa grade cold-rolled steel plate, the composition and its mass percentage are: C: 0.06%, Si: 0.1%, Mn: 0.95%, Nb: 0.03%, Ti: 0.03%, the rest is Fe and unavoidable impurity elements; the ingot is forged into a 50mm thick slab;

[0077] Step 2, hot rolling:

[0078] (1) Heat the forged slab at 1250°C for 3 hours;

[0079] (2) Hot-rolling the slab after heat preservation, th...

Embodiment 3

[0094] A cold-rolled steel plate with a yield strength of 500MPa, the composition and mass percentage are: C: 0.09%, Si: 0.03%, Mn: 0.8%, Nb: 0.04%, Ti: 0.02%, and the rest is Fe and unavoidable impurities element; its thickness is 0.5 mm.

[0095] The preparation method of above-mentioned yield strength 500MPa grade cold-rolled steel plate, comprises the steps:

[0096] Step 1, smelting and forging:

[0097] According to the chemical composition of the 500MPa yield strength cold-rolled steel plate, the raw materials are selected and mixed, and then melted into ingots; among them, the yield strength 500MPa grade cold-rolled steel plate, the composition and its mass percentage are: C: 0.09%, Si: 0.03% , Mn: 0.8%, Nb: 0.04%, Ti: 0.02%, the rest is Fe and unavoidable impurity elements; the ingot is forged into a 35mm thick slab;

[0098] Step 2, hot rolling:

[0099] (1) Insulate the forged slab at 1200°C for 3 hours;

[0100] (2) Hot-rolling the slab after heat preservation,...

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Abstract

The invention provides a cold-rolled steel plate with yield strength of 500MPa and a preparation method thereof, and belongs to the technical field of metallurgy. The steel plate components, by mass, are: 0.06-0.09% of C, 0-0.2% of Si, 0.8-1.0% of Mn, 0.03-0.05% of Ti, 0.02-0.04% of Nb, and the balance Fe and inevitable impurity elements. The preparation method comprises the following steps: 1) according to the chemical composition ratio of the cold-rolled steel plate, smelting into a casting billet; 2) performing thermal insulating on the casting billet, performing hot rolling to obtain a hot-rolled plate, cooling the hot-rolled plate to an appropriate temperature at a certain cooling rate and then coiling the hot-rolled plate; 3) after pickling the coiled hot-rolled plate, performing cold rolling to obtain a cold-rolled plate; and 4) performing continuous annealing treatment on the cold-rolled plate with segmented heating and segmented cooling. According to the cold-rolled steel plate, the microstructure mainly includes ferrite, pearlite and cementite, the yield strength is 530-560MPa, the tensile strength is 580-615MPa, elongation rate A80 is 21.3-22.5%, and the yield ratio is greater than or equal to 0.90.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a cold-rolled steel plate with a yield strength of 500 MPa and a preparation method thereof. Background technique [0002] Automobile lightweight is the key technical route of automobile "energy saving and emission reduction": every 10% reduction in vehicle weight can reduce fuel consumption by 6%-8% and reduce carbon dioxide emissions by 13%. The high strength of automobile steel is an important direction to realize the lightweight of automobiles. By increasing the use of high-strength steel plates to strengthen the body structure, its crash safety can be improved. Therefore, the use of high-strength steel plates can take into account both the lightweight of the car body and the need to improve crash safety. [0003] Due to its good strong plasticity, dual-phase steel accounts for a large proportion of automotive steel. However, due to the difference in hardness...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/04C22C38/12C22C38/14C22C38/02C21D8/02
CPCC21D8/0226C21D8/0236C21D8/0273C21D2211/003C21D2211/005C21D2211/009C22C38/02C22C38/04C22C38/12C22C38/14
Inventor 蓝慧芳杜林秀王国栋李建平邱春林李强
Owner NORTHEASTERN UNIV LIAONING
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