CN112981252A - 1500 MPa-grade steel plate for automobile and production method thereof - Google Patents
1500 MPa-grade steel plate for automobile and production method thereof Download PDFInfo
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- CN112981252A CN112981252A CN202110173933.0A CN202110173933A CN112981252A CN 112981252 A CN112981252 A CN 112981252A CN 202110173933 A CN202110173933 A CN 202110173933A CN 112981252 A CN112981252 A CN 112981252A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0242—Flattening; Dressing; Flexing
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
The invention relates to a 1500 MPa-grade steel plate for an automobile and a production method thereof, wherein the steel plate comprises the following chemical components in percentage by weight: 0.17-0.21% of C; si: 0.15-0.2%; mn: 1.3-1.7%; and Als: 0.03-0.05%; p is less than or equal to 0.03 percent; s is less than or equal to 0.01 percent; less than or equal to 0.005 percent of N, and the balance of Fe and inevitable impurities. The production method comprises the working procedures of hot rolling, cold rolling, annealing, flattening and hot forming. The tensile strength of the steel plate for the automobile obtained by the method is 1500-1600 MPa, the yield strength is 1000-1200 MPa, and the elongation is more than or equal to 5%.
Description
Technical Field
The invention belongs to the technical field of steel plate production, and particularly relates to a 1500 MPa-grade automobile steel plate and a production method thereof.
Background
The automobile industry in China is rapidly developed, the automobile is lightened into a new wind vane, the adoption of the ultrahigh-strength steel plate can effectively reduce the dead weight of the automobile, reduce the oil consumption, reduce the exhaust emission, improve the safety and reduce the environmental pollution, and therefore the development and the application of the ultrahigh-strength steel are concerned.
At present, important safety parts of a vehicle body, such as an A column, a B column and the like, adopt ultrahigh-strength steel with the tensile strength of more than 1500MPa for part of vehicles. Because the intensity is higher, adopt cold forming easily to produce problems such as fracture, precision difference, and easily reduce the life of mould. In order to meet the development requirement of the automobile industry, 1500 MPa-grade hot forming steel can be obtained after a special heat treatment forming process is developed. The hot-formed high-strength steel has the advantages of high strength, high forming precision and small resilience while greatly improving the weight reduction effect and safety of the automobile, and is widely used in the field of automobiles.
The existing 1500 MPa-grade ultrahigh-strength steel meets the high-performance requirement mainly by increasing the content of C, Mn and Cr elements or adding a certain amount of alloy elements, the problem of poor welding performance can be caused by the excessively high content of C, Mn elements, and the production cost can be increased by adding the alloy elements.
Chinese patent publication No. CN104561790B discloses "1500 MPa grade high strength steel and a production method thereof", wherein the steel comprises the following chemical components in percentage by weight: c: 0.20-0.30%; si: 1.50-1.80%; mn: 2.00-2.50%; ti: 0.02-0.06%; b: 0.002-0.005%; al: 0.015-0.06%, and obtaining the high-strength steel with tensile strength of 1500MPa and impact toughness of more than or equal to 50J after steel making, rolling and tempering heat treatment. But the carbon equivalent in the component design is higher, and the welding performance of the product is poorer.
Patent number CN103320700B discloses '1500 MPa grade steel for automobile safety parts and a production method thereof', wherein the steel comprises the following chemical components in percentage by weight: 0.23-0.26% of C, Si: 0.20 to 0.35%, Mn 1.0 to 1.6%, P not more than 0.015%, S not more than 0.008%, ALs 0.015 to 0.060%, Cr 0.20 to 0.50%, B0.0005 to 0.002%, Nb 0.010 to 0.025%, or Ti: 0.010-0.030 percent or Nb and Ti are mixed according to any proportion not more than 0.050 percent, N is less than or equal to 0.005 percent, and O is less than or equal to 0.005 percent; smelting, hot rolling, acid washing, cold rolling, annealing and heating in protective atmosphere; molding; quenching; tempering at low temperature; the product with tensile strength more than or equal to 1500MPa is obtained. But the equivalent of C in the component design is higher, which affects the welding performance of the material; in addition, a certain amount of Nb and Ti alloy elements are added into the components, and low-temperature tempering is carried out after quenching, so that the production cost is obviously increased.
Disclosure of Invention
The invention aims to solve the technical problem of providing a 1500 MPa-grade automobile steel plate and a preparation method thereof, wherein the 1500 MPa-grade automobile steel plate is obtained at low cost by adopting a low alloy component system and through process control.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: the 1500 MPa-grade steel plate for the automobile is characterized by comprising the following chemical components in percentage by weight: 0.17-0.21% of C; si: 0.15-0.2%; mn: 1.3-1.7%; and Als: 0.03-0.05%; p is less than or equal to 0.03 percent; s is less than or equal to 0.01 percent; less than or equal to 0.005 percent of N, and the balance of Fe and inevitable impurities.
The proportion and the effect of each element in the steel are as follows:
the effects of the elements disclosed by the invention are as follows:
c: carbon is an effective strengthening element and can greatly improve the strength of steel, but the welding performance is influenced by the excessively high content of carbon, so that the content of C in the invention is designed to be 0.17-0.21 wt%.
Si: silicon can promote ferrite precipitation, but the surface quality is reduced due to the excessively high content of silicon, and the plasticity and the welding performance are influenced, so that the Si content is designed to be 0.15-0.2 wt%.
Mn: manganese is an austenite stabilizing element, has an obvious inhibiting effect on an austenite recrystallization process, and can play a role in solid solution strengthening and grain refinement, so that the Mn content of the invention is designed to be 1.3-1.7 wt%.
And Als: the alloy plays roles of deoxidizing and refining grains in steel, so that the content of Als is designed to be 0.03-0.05 wt%.
P, S, N element is an impurity element in steel, the lower the content, the better, considering the production cost, the P content is designed to be less than or equal to 0.03wt%, the S content is designed to be less than or equal to 0.01wt%, and the N content is designed to be less than or equal to 0.005 wt%.
The production method of the 1500 MPa-grade automobile steel plate comprises the working procedures of hot rolling, cold rolling, annealing, leveling and hot forming and is characterized in that the hot forming working procedure is to perform machining forming after heating and heat preservation of the steel plate, the heating and heat preservation process is performed under the protective atmosphere, the protective atmosphere is nitrogen, the heating temperature is 900-960 ℃, the heat preservation time is 3-6 minutes, the forming temperature is 850-880 ℃, rapid cooling is performed after forming, and the critical cooling speed is more than or equal to 80 ℃/s.
Further, the molded product is rapidly cooled, and the cooling medium is water.
Hot forming is carried out on the steel plate after smelting, continuous casting, hot rolling, cold rolling, annealing and flattening. A thermal forming procedure, namely heating the steel plate to 900-960 ℃ under a protective atmosphere, and preserving heat for 3-6 minutes to ensure that the internal tissue of the plate is completely austenitized; the sheet material after heating and heat preservation is processed and formed, and the austenite structure has good plasticity and low strength, so the sheet material is very suitable for processing. The hot forming temperature is kept at 850-880 ℃; the final organization structure of the plate can be influenced by the cooling rate, and the hardenability of the plate can be ensured by the higher cooling rate. And (3) rapidly cooling the formed part by using a water cooling system to ensure that the metallographic structure of the plate is completely changed into a martensite structure, wherein the critical cooling rate is more than or equal to 80 ℃/s, and finally obtaining the ultra-high strength steel product with the tensile strength reaching 1500 MPa.
Further, the annealing process is continuous annealing, the steel plate is heated to 750-800 ℃ at a heating rate of 1-3 ℃/s, is subjected to heat preservation for 120-150 s, is slowly cooled to 650-700 ℃, and is rapidly cooled to 350-400 ℃ at a cooling speed of 10-20 ℃/s.
Further, the slow cooling is carried out by adopting hydrogen gas for air cooling.
Further, after the steel plate is cooled to 350-400 ℃, overaging treatment is carried out for 250-400 s.
Further, in the leveling process, the leveling elongation is 0.4-0.7%.
Further, in the hot rolling process, the plate blank is heated to 1230-1270 ℃, the finishing temperature is controlled to 880-920 ℃, the plate blank is cooled to 630-670 ℃ through a laminar cooling system after rolling, and then coiling is carried out, namely the coiling temperature is 630-670 ℃.
Further, in the cold rolling step, the cold rolling reduction is controlled to be 50-60%.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in:
the tensile strength of the steel plate for the automobile obtained by the method is 1500-1600 MPa, the yield strength is 1000-1200 MPa, and the elongation is more than or equal to 5%.
Detailed Description
The invention relates to a production method of 1500 MPa-grade steel plates for automobiles, which comprises the working procedures of hot rolling, cold rolling, annealing, flattening and hot forming,
a hot rolling procedure, namely heating the plate blank to 1230-1270 ℃, controlling the final rolling temperature to 880-920 ℃, cooling to 630-670 ℃ through a laminar cooling system after rolling, and then coiling;
a cold rolling process, wherein the cold rolling reduction is controlled to be 50-60%;
the annealing process is continuous annealing, the steel plate is heated to the temperature of 750-800 ℃ at the T1 temperature at the heating rate HR1 of 1-3 ℃/s, the steel plate is slowly cooled to the temperature of 650-700 ℃ at the T2 temperature after being kept for 120-150 s, hydrogen is adopted for air cooling in the slow cooling process, then the steel plate is quickly cooled to the temperature of 350-400 ℃ at the T3 temperature at the cooling rate CR1 of 10-20 ℃/s, and overaging treatment is carried out for 250-400 s;
and (5) a leveling process, wherein the leveling elongation is 0.4-0.7%.
And a thermal forming process, namely heating and insulating the steel plate in a protective atmosphere, then processing and forming the steel plate, wherein the protective atmosphere is nitrogen, the heating temperature is 900-960 ℃, the insulating time is 3-6 minutes, the forming temperature is 850-880 ℃, and the steel plate is rapidly cooled after forming, the cooling medium is water, and the critical cooling speed is more than or equal to 80 ℃/s.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Examples 1 to 10
The chemical compositions and weight percentages of the steel plates of examples 1-10 are shown in Table 1, the technological parameters of the hot rolling process and the cold rolling process are shown in Table 2, the technological parameters of the annealing process are shown in Table 3, and the technological parameters of the leveling process and the hot forming process are shown in Table 4.
TABLE 1
TABLE 2
TABLE 3
TABLE 4
The mechanical properties of the steel plates of the finished products of the examples 1 to 10 are detected, and the detection results are shown in Table 5.
TABLE 5
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (9)
1. The 1500 MPa-grade steel plate for the automobile is characterized by comprising the following chemical components in percentage by weight: 0.17-0.21% of C; si: 0.15-0.2%; mn: 1.3-1.7%; and Als: 0.03-0.05%; p is less than or equal to 0.03 percent; s is less than or equal to 0.01 percent; less than or equal to 0.005 percent of N, and the balance of Fe and inevitable impurities.
2. The production method of the 1500 MPa-grade steel plate for the automobile according to claim 1, which comprises the working procedures of hot rolling, cold rolling, annealing, flattening and hot forming, and is characterized in that the hot forming working procedure is to perform machining and forming after heating and heat preservation of the steel plate, the heating and heat preservation processes are performed under a protective atmosphere, the protective atmosphere is nitrogen, the heating temperature is 900-960 ℃, the heat preservation time is 3-6 minutes, the forming temperature is 850-880 ℃, rapid cooling is performed after forming, and the critical cooling speed is not less than 80 ℃/s.
3. The production method of the 1500 MPa-grade steel plate for the automobile according to claim 2, characterized in that the rapid cooling is performed after the forming, and the cooling medium is water.
4. The production method of the 1500 MPa-grade steel plate for the automobile according to claim 2, wherein the annealing process is continuous annealing, the steel plate is heated to 750-800 ℃ at a heating rate of 1-3 ℃/s, is subjected to heat preservation for 120-150 s, is slowly cooled to 650-700 ℃, and is then rapidly cooled to 350-400 ℃ at a cooling rate of 10-20 ℃/s.
5. The production method of the 1500 MPa-grade steel plate for the automobile according to claim 4, wherein the slow cooling is carried out by using hydrogen gas for air cooling.
6. The production method of the 1500 MPa-grade steel plate for the automobile according to claim 4, wherein the steel plate is cooled to 350-400 ℃, and then is subjected to overaging treatment for 250-400 s.
7. The production method of the 1500 MPa-grade steel plate for the automobile as claimed in claim 2, wherein in the flattening process, the flattening elongation is 0.4-0.7%.
8. The production method of the 1500 MPa-grade steel plate for the automobile according to claim 2, characterized in that in the hot rolling process, the plate blank is heated to 1230-1270 ℃, the final rolling temperature is controlled to 880-920 ℃, and the plate blank is cooled to 630-670 ℃ through a laminar cooling system after rolling and then coiled.
9. The method for producing a 1500MPa grade steel sheet for automobiles according to claim 2, wherein the cold rolling step is performed with a cold rolling reduction ratio controlled to 50 to 60%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110173933.0A CN112981252A (en) | 2021-02-06 | 2021-02-06 | 1500 MPa-grade steel plate for automobile and production method thereof |
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| CN202110173933.0A CN112981252A (en) | 2021-02-06 | 2021-02-06 | 1500 MPa-grade steel plate for automobile and production method thereof |
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| CN112981252A true CN112981252A (en) | 2021-06-18 |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101301876A (en) * | 2008-04-28 | 2008-11-12 | 长安福特马自达汽车有限公司 | Low-alloy high-strength steel automobile rear bumper beam and manufacturing method thereof |
| JP2010242164A (en) * | 2009-04-06 | 2010-10-28 | Jfe Steel Corp | Method for manufacturing high strength welded steel tube for automobile structural member |
| CN106086348A (en) * | 2016-07-27 | 2016-11-09 | 唐山钢铁集团有限责任公司 | A kind of cold rolling bailing band of high-strength high-elongation ratio and manufacture method thereof |
| CN106947919A (en) * | 2017-03-21 | 2017-07-14 | 马钢(集团)控股有限公司 | A kind of high-toughness hot forming steel and its production method |
| CN109628846A (en) * | 2018-12-20 | 2019-04-16 | 唐山钢铁集团有限责任公司 | 1300MPa grades of automobile super high tensile cold-rolled steel plates and its production method |
| CN110592471A (en) * | 2019-08-26 | 2019-12-20 | 邯郸钢铁集团有限责任公司 | 1200 MPa-grade cold-rolled martensite steel plate and preparation method thereof |
| CN111321341A (en) * | 2019-12-03 | 2020-06-23 | 马鞍山钢铁股份有限公司 | 1500 MPa-grade non-coating hot forming steel with low high-temperature friction coefficient and preparation method thereof |
| CN111748736A (en) * | 2020-06-24 | 2020-10-09 | 武汉钢铁有限公司 | 1800 MPa-grade low-hydrogen delayed cracking sensitive hot forming steel and production method thereof |
-
2021
- 2021-02-06 CN CN202110173933.0A patent/CN112981252A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101301876A (en) * | 2008-04-28 | 2008-11-12 | 长安福特马自达汽车有限公司 | Low-alloy high-strength steel automobile rear bumper beam and manufacturing method thereof |
| JP2010242164A (en) * | 2009-04-06 | 2010-10-28 | Jfe Steel Corp | Method for manufacturing high strength welded steel tube for automobile structural member |
| CN106086348A (en) * | 2016-07-27 | 2016-11-09 | 唐山钢铁集团有限责任公司 | A kind of cold rolling bailing band of high-strength high-elongation ratio and manufacture method thereof |
| CN106947919A (en) * | 2017-03-21 | 2017-07-14 | 马钢(集团)控股有限公司 | A kind of high-toughness hot forming steel and its production method |
| CN109628846A (en) * | 2018-12-20 | 2019-04-16 | 唐山钢铁集团有限责任公司 | 1300MPa grades of automobile super high tensile cold-rolled steel plates and its production method |
| CN110592471A (en) * | 2019-08-26 | 2019-12-20 | 邯郸钢铁集团有限责任公司 | 1200 MPa-grade cold-rolled martensite steel plate and preparation method thereof |
| CN111321341A (en) * | 2019-12-03 | 2020-06-23 | 马鞍山钢铁股份有限公司 | 1500 MPa-grade non-coating hot forming steel with low high-temperature friction coefficient and preparation method thereof |
| CN111748736A (en) * | 2020-06-24 | 2020-10-09 | 武汉钢铁有限公司 | 1800 MPa-grade low-hydrogen delayed cracking sensitive hot forming steel and production method thereof |
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Application publication date: 20210618 |
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