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Cold-rolled steel sheet with 420 MPa grade yield strength and preparation method of steel sheet

A technology of yield strength and cold-rolled steel plate, which is applied in the field of cold-rolled steel plate with a yield strength of 420MPa and its preparation, can solve the problems of increasing difficulty in controlling the surface quality of the strip steel, improving the diffusion ability, and affecting the surface quality of the strip steel, achieving a reduction in Difficulty in controlling the surface quality of strip steel, the reduction in the growth rate of precipitated particles, and the effect of good precipitation strengthening effect

Active Publication Date: 2017-05-10
NORTHEASTERN UNIV LIAONING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the Nb content in this method is 0.04% to 0.05%, and the cost is relatively high
[0008] All adopted high-temperature soaking in the above-mentioned method, this will bring the following problems: (1) under high temperature, hearth roll nodulation very easily takes place, thus easily causes scratch to strip steel in operation process, affects strip surface quality (2) Under high temperature soaking conditions, the precipitated particles are prone to coarsening, and at the same time, the ferrite grains are easy to grow, resulting in a decrease in strength; (3) Under high temperature, the diffusion ability of Si and Mn elements is improved, and the selective oxidation is intensified , it is more difficult to control the surface quality of strip steel; (4) The energy consumption increases at high temperature, and the heating cost is higher

Method used

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  • Cold-rolled steel sheet with 420 MPa grade yield strength and preparation method of steel sheet

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] A cold-rolled steel plate with a yield strength of 420MPa, the composition and mass percentage are: C: 0.06%, Si: 0.04%, Mn: 0.8%, Nb: 0.025%, and the rest is Fe and unavoidable impurity elements; its thickness is 1mm.

[0053] The preparation method of the above-mentioned yield strength 420MPa grade cold-rolled steel plate comprises the steps:

[0054] Step 1, smelting and forging:

[0055] According to the chemical composition of the 420MPa yield strength cold-rolled steel plate, the raw materials are selected and blended, and then melted into ingots; among them, the yield strength 420MPa grade cold-rolled steel plate, the composition and its mass percentage are: C: 0.06%, Si: 0.04%, Mn: 0.8%, Nb: 0.025%, the rest is Fe and unavoidable impurity elements; the ingot is forged into a 40mm thick slab;

[0056] Step 2, hot rolling:

[0057] (1) Insulate the forged slab at 1220°C for 2 hours;

[0058] (2) hot-rolling the slab after heat preservation, the rolling start t...

Embodiment 2

[0073] A cold-rolled steel plate with a yield strength of 420MPa, the composition and mass percentage are: C: 0.07%, Si: 0.1%, Mn: 0.9%, Nb: 0.025%, and the rest is Fe and unavoidable impurity elements; its thickness is 1.8mm.

[0074] The preparation method of the above-mentioned yield strength 420MPa grade cold-rolled steel plate comprises the steps:

[0075] Step 1, smelting and forging:

[0076] According to the chemical composition of the 420MPa yield strength cold-rolled steel plate, the raw materials are selected and mixed, and then smelted into ingots; among them, the yield strength 420MPa grade cold-rolled steel plate, the composition and its mass percentage are: C: 0.07%, Si: 0.1%, Mn: 0.9%, Nb: 0.025%, the rest is Fe and unavoidable impurity elements; the ingot is forged into a 50mm thick slab;

[0077] Step 2, hot rolling:

[0078] (1) Insulate the forged slab at 1220°C for 2 hours;

[0079] (2) hot-rolling the slab after heat preservation, the starting rolling...

Embodiment 3

[0094] A cold-rolled steel plate with a yield strength of 420MPa, the composition and mass percentage of which are C: 0.06%, Si: 0.04%, Mn: 1.0%, Nb: 0.02%, and the rest is Fe and unavoidable impurity elements; its thickness is 1.2 mm.

[0095] The preparation method of the above-mentioned yield strength 420MPa grade cold-rolled steel plate comprises the steps:

[0096] Step 1, smelting and forging:

[0097] According to the chemical composition of the 420MPa yield strength cold-rolled steel plate, the raw materials are selected and mixed, and then smelted into ingots; among them, the yield strength 420MPa grade cold-rolled steel plate, the composition and its mass percentage are C: 0.06%, Si: 0.04%, Mn : 1.0%, Nb: 0.02%, the rest is Fe and unavoidable impurity elements; the ingot is forged into a 50mm thick slab;

[0098] Step 2, hot rolling:

[0099] (1) Heat the forged slab at 1230°C for 2.5 hours;

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

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Abstract

The invention discloses a cold-rolled steel sheet with the 420 MPa grade yield strength and a preparation method of the steel sheet and belongs to the technical field of metallurgy. The steel sheet is prepared from components in percentage by mass as follows: 0.06%-0.09% of C, 0-0.2% of Si, 0.8%-1.0% of Mn, 0-0.02% of Ti, 0.01%-0.025% of Nb and the balance of Fe and inevitable impurity elements. The preparation method comprises steps as follows: (1) according to the ratio of the chemical components of the cold-rolled steel sheet, a steel ingot is obtained through smelting and is forged to form a slab; (2) heat preservation is performed on the slab, hot rolling is performed, and a hot-rolled sheet is prepared and is cooled to the proper temperature at a certain cooling rate for coiling; (3) the coiled hot-rolled sheet is pickled and then cold-rolled, and the cold-rolled sheet is prepared; (4) the cold-rolled sheet is subjected to continuous annealing treatment of low-temperature soaking and step cooling. According to the cold-rolled steel sheet, the microstructure mainly comprises ferrite, pearlite and cementite, the yield strength of the steel sheet ranges from 435 MPa to 450 MPa, the tensile strength ranges from 518 MPa to 548 MPa, and the ductility A80 ranges from 25.0% to 26.3%.

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 420 MPa and a preparation method thereof. Background technique [0002] Lightweight automobile body can reduce energy consumption and CO 2 emissions purposes. Lightweight has been proved to be 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%. China is the world's largest producer and consumer of automobiles, and lightweight has become an important issue for the sustainable development of the automobile industry. The high strength of automobile steel is an effective way to realize the lightweight of automobiles, and the high strength of automobile steel has become an inevitable trend. By strengthening the body structure by increasing the use of high-strength steel plat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/14C22C38/12C21D8/02C21D1/26
CPCC21D1/26C21D8/0226C21D8/0236C21D8/0273C21D2211/003C21D2211/005C21D2211/009C22C38/02C22C38/04C22C38/12C22C38/14
Inventor 蓝慧芳杜林秀王国栋李建平李强邱春林
Owner NORTHEASTERN UNIV LIAONING
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