CN111996459A - CSP (cast steel plate) process-based special high-strength steel plate for automobile with grade of more than 1000Mpa and manufacturing method thereof - Google Patents
CSP (cast steel plate) process-based special high-strength steel plate for automobile with grade of more than 1000Mpa and manufacturing method thereof Download PDFInfo
- Publication number
- CN111996459A CN111996459A CN202010892600.9A CN202010892600A CN111996459A CN 111996459 A CN111996459 A CN 111996459A CN 202010892600 A CN202010892600 A CN 202010892600A CN 111996459 A CN111996459 A CN 111996459A
- Authority
- CN
- China
- Prior art keywords
- steel plate
- strength steel
- strength
- pressure
- csp
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- 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
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- 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
- C21D2211/002—Bainite
-
- 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
- C21D2211/005—Ferrite
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical 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 discloses a special automobile high-strength steel plate based on a CSP (compact strip production) process, which comprises the following chemical components in percentage by mass: 0.20-0.25% of C, 0.25-0.3% of Si, 1.0-1.3% of Mn, 0.2-0.35% of Cr, 0.003-0.005% of B, 0.025-0.030% of Ti, 0.02-0.05% of Als, less than or equal to 0.010% of P, less than or equal to 0.005% of S, less than or equal to 0.005% of N, and the balance of Fe and other inevitable impurities. According to the invention, by combining steel component design and CSP (cast steel plate) process and further optimizing laminar cooling process, high-strength steel with yield strength of 700-970 MPa, tensile strength of 1050-1300 MPa and elongation rate of more than or equal to 6% is obtained; and bainite is further introduced into the dual-phase high-strength steel system to adjust the structure and the performance of the steel, so that the processing performance of the high-strength steel plate is effectively improved.
Description
Technical Field
The invention belongs to the technical field of high-strength steel preparation, and particularly relates to a special automobile high-strength steel plate with the strength of more than 1000MPa based on a CSP (compact strip production) process and a manufacturing method thereof.
Background
As the automotive industry develops, energy conservation, environmental protection, and safety become important factors to be considered in the design and manufacture of automobiles. The development of the industries of not only passenger vehicles but also special vehicles requires the materials for the vehicles to be more and more light and highly strengthened. The adoption of high-strength steel is an economical and practical way, and the weight can be greatly reduced without reducing the safety. At present, the field of special vehicles mainly uses the conventional hot rolling or cold rolling process to prepare high-strength steel.
In recent decades, the technology of continuous casting and rolling of thin slabs has made great progress and is widely popularized and applied. The thin slab continuous casting and rolling process can be used for directly rolling and producing thin steel plates with the thickness of 0.8-2.0 mm, and high-strength steel which can only be produced by using the conventional hot rolling and cold rolling processes is replaced by the thin steel plates directly rolled by the continuous casting and rolling process. Compared with cold rolling and conventional hot rolling, the thin slab continuous casting and rolling process can effectively shorten the process flow and greatly reduce the energy consumption. At present, the thin slab continuous casting and rolling technology which is put into industrial production comprises a CSP technology, a TFSR technology, an ISP technology and the like.
Chinese patent CN107557692B discloses 1000 MPa-grade hot-rolled TRIP steel based on CSP process, which comprises the following chemical element components in percentage by weight: 0.16-0.20% of C, 1.60-1.80% of Si, 1.50-1.60% of Mn, 0.20-0.24% of V, less than or equal to 0.008% of P, less than or equal to 0.005% of S, 0.015-0.060% of Als, 0.015-0.025% of N, and the balance of iron and inevitable impurities; the high-Si design is adopted in the component design, the precipitation of carbide is inhibited, and therefore partial retained austenite is obtained, and the high-Si high-strength steel is mainly suitable for automobile structural parts with high requirements on plasticity. Chinese patent CN107641700B discloses a method for producing thin hot-rolled DP1180 steel based on CSP process, which comprises the following chemical elements in percentage by weight: 0.17-0.20% of C, 0.50-0.70% of Si, 1.30-1.50% of Mn, 0.40-0.70% of Cr, 0.02-0.07% of Als, less than or equal to 0.030% of P, less than or equal to 0.008% of S, and the balance of Fe and inevitable impurities, wherein the structure is martensite and ferrite, the martensite and ferrite have large strength and plasticity difference, and the steel plate has cracking risk when being processed (such as large deformation bending and the like).
Disclosure of Invention
The invention mainly aims to provide a high-strength steel plate with low cost, yield strength of more than 700MPa and tensile strength of more than 1000MPa aiming at the defects in the prior art, and the structure and the performance of the steel plate are adjusted by introducing bainite with strength and plasticity between ferrite and martensite, so that the processing performance of the steel plate is improved; compared with the conventional hot rolling and cold rolling, the adopted CSP process can effectively reduce the production cost.
In order to achieve the purpose, the invention adopts the technical scheme that:
a CSP process-based special automobile high-strength steel plate with the pressure of more than 1000Mpa comprises the following chemical components in percentage by mass: 0.20-0.25% of C, 0.25-0.3% of Si, 1.0-1.3% of Mn, 0.2-0.35% of Cr, 0.003-0.005% of B, 0.025-0.030% of Ti, 0.02-0.05% of Als, less than or equal to 0.010% of P, less than or equal to 0.005% of S, less than or equal to 0.005% of N, and the balance of Fe and other inevitable impurities; is prepared by a CSP process.
In the scheme, the metallographic structure of the special automobile high-strength steel plate comprises ferrite, bainite and martensite; wherein each tissue and the volume percentage thereof comprise: 5-20% of ferrite, 5-20% of bainite and 60-80% of martensite.
In the scheme, the martensite lath is fine and has the size of 8-12 mu m.
In the scheme, the yield strength of the special automobile high-strength steel plate is 700-970 MPa, the tensile strength is 1050-1300 MPa, and the elongation is more than or equal to 6%.
The preparation method of the special automobile high-strength steel plate with the pressure of more than 1000Mpa based on the CSP process mainly comprises the steps of smelting, refining, thin slab continuous casting, casting blank soaking, rolling, laminar cooling, reeling and leveling;
wherein the charging temperature of the casting blank is 850-950 ℃, and the discharging temperature is 1190-1210 ℃;
the rolling pass reduction distribution is as follows: 50-60% of the first pass, 50-60% of the second pass and 10-16% of the last pass; controlling the rolling speed to be 8-12 m/s; the finishing temperature is 850-890 ℃.
In the scheme, the smelting step is smelting in an electric furnace or a converter.
In the scheme, in the thin slab continuous casting step, the superheat degree of the tundish molten steel is 15-30 ℃.
In the scheme, the thickness of a casting blank for continuous casting of the thin slab is 52-55 mm, and the drawing speed is 3.7-4.5 m/s.
In the scheme, the continuous casting blank of the sheet billet is descaled before entering the furnace, and the descaling pressure is 300-400 bar.
In the scheme, the soaking pit furnace adopts a weak oxidation atmosphere, and the residual oxygen in the furnace is 0.5-3.0%.
In the scheme, the descaling process in the rolling process is to remove scale by adopting high-pressure water before entering a rolling mill, and the pressure (high pressure) of the descaling water is 280-420 bar; and (3) removing scale by medium-pressure water between the F1 rolling mill and the F2 rolling mill, wherein the pressure (medium pressure) of the scale removing water is 200-280 bar.
In the scheme, in the laminar cooling process, the temperature is quickly cooled to 700-550 ℃ at the cooling rate of 80-120 ℃/s; air cooling for 3-8 s; then rapidly cooling to 230-280 ℃ at a cooling rate of 100-150 ℃/s.
In the scheme, the coiling temperature is 230-280 ℃; and flattening the steel coil after the temperature of the steel coil is reduced to below 50 ℃.
In the scheme, the thickness of the obtained strip steel finished product is 0.8-2.0 mm.
The principle of the invention is as follows:
1) the invention adopts low-alloy and low-cost design according to the principle of component design, and the content of main alloy elements is controlled as follows:
c: carbon is the most basic strengthening element in steel; the higher the carbon content is, the higher the yield strength and tensile strength of the steel are, but the plasticity and toughness are reduced, and the higher the carbon content is, the welding performance of the steel is reduced; the invention controls the carbon content in the range of 0.20-0.25%.
Si: silicon is a commonly used deoxidizer in steel making; silicon does not generate carbide in steel, exists in ferrite or austenite in the form of solid solution, and improves the strength of the solid solution; silicon can improve the hardenability of steel, can play a role in reducing the volume change when the austenite is transformed into martensite, and effectively controls the generation of quenching cracks; during low-temperature tempering, silicon can reduce the diffusion rate of carbon and increase the tempering stability and strength of steel; too high a silicon content will significantly reduce the plasticity, toughness and weldability of the steel; the invention controls the silicon content in the range of 0.25-0.30%.
Mn: manganese is an excellent deoxidizer and desulfurizer in steel making; manganese and sulfur form high-melting-point MnS, so that the hot brittleness phenomenon caused by FeS is prevented; manganese can not only improve the strength of steel, but also obviously improve the hardenability of the steel and ensure that martensite is obtained at a proper cooling speed; however, too high manganese increases the grain coarsening tendency and the temper brittleness sensitivity; the invention controls the manganese content in the range of 1.0-1.3%.
Cr: chromium can improve the hardenability of steel, can strengthen a matrix in a solid solution way, and improves the tempering stability of the steel; the invention controls the chromium content within the range of 0.20-0.35%.
B: boron is an element which strongly improves hardenability; trace boron can block ferrite nucleation on a grain boundary, prolong the incubation period of austenite and improve the hardenability of steel; the invention controls the boron content within the range of 0.003-0.005%.
Ti: titanium is a strong C, N-forming element, and can fix the N element in steel; the solid solution strengthening effect of the solid solution titanium is extremely strong, and the hardenability of the steel can be obviously improved by the titanium dissolved in austenite; however, excessive Ti compounds promote the decomposition of austenite and reduce the hardenability of steel; the invention controls the titanium content in the range of 0.025-0.030%.
2) The principle of the process improvement is that,
the laminar cooling process is crucial to the structure and performance of the steel plate; unlike conventional dual-phase steel formed by ferrite and martensite, the invention is based on the above composition design requirements and further adjusts the steel properties by introducing bainite with strength and plasticity between those of ferrite and martensite, and the specific control steps are as follows:
water cooling in the first stage: and (3) rapidly cooling the steel plate from the finishing temperature of 850-890 ℃ to 700-550 ℃, wherein the cooling rate is 80-120 ℃/s in a ferrite or bainite generation area.
Air cooling: air cooling for 3-8 s to generate partial ferrite or partial bainite or partial ferrite and bainite; wherein the generation of ferrite is helpful to improve the plasticity of the material, and the strength of bainite is higher than that of ferrite; the amounts of ferrite, bainite and unconverted austenite are adjusted by adjusting the water cooling end point temperature and the air cooling time of the first stage, so that the relative contents of a soft phase (ferrite) and a hard phase (martensite and bainite) in the final multi-phase structure are controlled, and the material performance is adjusted; a higher first stage water cooling end point temperature contributes to the increase of the ferrite content, and a lower first stage water cooling end point temperature increases the bainite content.
Water cooling at the second stage: rapidly cooling to below the martensite generation point, and generating martensite from the unconverted austenite; the cooling end point is 230-280 ℃, and the cooling speed is 100-150 ℃/s; the final structure is ferrite (5-20%) + bainite (5-20%) + fine lath-shaped martensite (60-80%).
Compared with the prior art, the invention has the beneficial effects that:
1) according to the invention, by combining steel component design and CSP (cast steel plate) process and further optimizing laminar cooling process, the high-strength steel with yield strength of 700-970 MPa, tensile strength of 1050-1300 MPa and elongation rate of more than or equal to 6% is prepared; meanwhile, based on the improvement means, the structure and the performance of the steel are adjusted by further introducing bainite into a ferrite/martensite dual-phase steel system, and the processing performance of the high-strength steel plate is effectively improved.
2) The high-strength steel obtained by the invention can be used for parts such as floors, door core plates, square tubes and the like of special vehicles, and is beneficial to the light weight of the special vehicles; the manufacturing process adopts the CSP process, the process scheme is feasible, compared with the conventional hot rolling and cold rolling, the CSP product has short manufacturing flow, and the production cost is reduced.
Drawings
FIG. 1 is a metallographic microstructure of a sample of the steel material obtained in example 1, consisting of ferrite, bainite and martensite.
Detailed Description
The present invention will be described in further detail with reference to specific examples below so that those skilled in the art can more clearly understand the present invention. The following should not be construed as limiting the scope of the claimed invention.
Examples 1 to 10
The preparation method of the special automobile high-strength steel plate based on the CSP process in the embodiment 1-10 comprises the following steps:
1) smelting according to the component requirements shown in Table 1, wherein S in the molten iron desulphurization step is less than or equal to 0.002%, and the exposed surface of the molten iron after slagging-off is more than or equal to 96%; smelting by adopting an electric furnace or a converter;
2) refining;
3) continuous casting; controlling the superheat degree of the tundish molten steel to be 15-30 ℃, the thickness of a casting blank to be 52-55 mm, and the pulling speed to be 3.7-4.5 m/min; carrying out descaling treatment on the casting blank before the casting blank is placed into a soaking furnace, wherein the pressure of descaling water is 300-400 bar;
4) soaking the casting blank; controlling the interior of the soaking pit to be in a weak oxidation atmosphere, wherein the residual oxygen in the pit is 0.5-3.0%;
5) the charging temperature of the casting blank is 850-950 ℃, and the discharging temperature is 1190-1210 ℃;
6) rolling; carrying out high-pressure water descaling before entering a rolling mill, wherein the pressure of the descaling water is 280-420 bar; removing scale by medium-pressure water between F1 and F2, wherein the pressure of the scale removing water is 200-280 bar; the rolling pass reduction distribution is controlled as follows: the first time: 50-60%, and in the second pass: 50-60%, last pass: 10-16%; controlling the rolling speed to be 8-12 m/s; a rolling process adopts a supporting roller for lubrication, and the final rolling temperature is 850-890 ℃;
7) laminar cooling; rapidly cooling to 700-550 ℃ at a cooling rate of 80-120 ℃/s; air cooling for 3-8 s; then rapidly cooling to 230-280 ℃ at a cooling rate of 100-150 ℃/s;
8) the coiling temperature is 230-280 ℃; and flattening the steel coil after the temperature of the steel coil is reduced to below 50 ℃.
Comparative examples 1 to 2
The preparation method of the steel materials of comparative examples 1-2 is substantially the same as that of the above examples, except that the mixing ratio and the process parameters of the steel materials are shown in tables 1 and 2, respectively.
TABLE 1 chemical composition (wt.%) of steels according to examples 1 to 10 and comparative examples 1 to 2
| Numbering | C | Si | Mn | Cr | Ti | B | Als | P | S | N |
| Examples 1 to 4 | 0.22 | 0.25 | 1.30 | 0.30 | 0.025 | 0.003 | 0.024 | 0.008 | 0.002 | 0.003 |
| Examples 5 to 6 | 0.20 | 0.25 | 1.00 | 0.20 | 0.025 | 0.005 | 0.021 | 0.008 | 0.003 | 0.002 |
| Examples 7 to 8 | 0.25 | 0.25 | 1.00 | 0.34 | 0.027 | 0.005 | 0.046 | 0.006 | 0.002 | 0.004 |
| Examples 9 to 10 | 0.25 | 0.30 | 1.30 | 0.31 | 0.030 | 0.003 | 0.030 | 0.007 | 0.002 | 0.002 |
| Comparative examples 1 to 2 | 0.22 | 0.25 | 1.30 | 0.30 | 0.025 | 0.003 | 0.024 | 0.008 | 0.002 | 0.003 |
TABLE 2 part of the Process parameters of the steels described in examples 1 to 10 and comparative examples 1 to 2
| Numbering | Final Rolling temperature/. degree.C | First stage cooling end point/. degree.C | Air cooling time/s | End point of second stage cooling/. degree.C |
| Example 1 | 890 | 700 | 7 | 280 |
| Example 2 | 890 | 650 | 6 | 280 |
| Example 3 | 890 | 550 | 4 | 280 |
| Example 4 | 890 | 550 | 4 | 230 |
| Example 5 | 890 | 700 | 7 | 280 |
| Example 6 | 890 | 650 | 6 | 280 |
| Example 7 | 860 | 700 | 7 | 280 |
| Example 8 | 860 | 650 | 6 | 280 |
| Example 9 | 860 | 700 | 7 | 230 |
| Example 10 | 860 | 550 | 4 | 230 |
| Comparative example 1 | 890 | 750 | 4 | 280 |
| Comparative example 2 | 890 | 750 | 4 | 230 |
The mechanical test results and the structure content of the steel materials obtained in examples 1 to 10 and comparative examples 1 to 2 are shown in Table 3.
TABLE 3 tensile properties and texture contents of samples of steels according to examples 1 to 10 and comparative examples 1 to 2
| Numbering | Yield strength/MPa | Tensile strength/Mpa | Elongation/percent | Ferrite/% of | Bainite/% of | Martensite/% of |
| Example 1 | 751 | 1150 | 9.7 | 13 | 17 | 70 |
| Example 2 | 772 | 1140 | 9.1 | 12 | 19 | 69 |
| Example 3 | 816 | 1190 | 8.9 | 6 | 21 | 73 |
| Example 4 | 933 | 1260 | 6.8 | 5 | 20 | 75 |
| Example 5 | 717 | 1030 | 10.4 | 20 | 8 | 72 |
| Example 6 | 794 | 1100 | 9.7 | 15 | 16 | 69 |
| Example 7 | 798 | 1210 | 7.4 | 14 | 15 | 71 |
| Examples8 | 854 | 1180 | 8.3 | 11 | 19 | 70 |
| Example 9 | 835 | 1180 | 8.8 | 19 | 16 | 65 |
| Example 10 | 967 | 1290 | 6.1 | 6 | 20 | 74 |
| Comparative example 1 | 621 | 1110 | 10.3 | 31 | 0 | 69 |
| Comparative example 2 | 652 | 1160 | 9.6 | 26 | 0 | 74 |
FIG. 1 is a metallographic microstructure of a steel sample obtained in example 1, wherein the metallographic structure is composed of ferrite, bainite and martensite, and martensite has fine laths with a size of 8-12 μm; in addition, through tests, the structures of the steel obtained in the embodiments 1-10 are ferrite (5-20%), bainite (5-20%) and martensite (60-80%); the steel obtained in the comparative examples 1-2 has ferrite and martensite, and the yield strength is lower than 700 MPa.
The steel products obtained in examples 1-10 and comparative examples 1-2 are respectively subjected to 180 DEG and 1T bending tests, the steel product sample obtained in the example of the invention has no crack after 3 tests, and the steel product sample obtained in the comparative example has a crack after 3 tests.
The above embodiments are merely examples for clearly illustrating the present invention and do not limit the present invention. Other variants and modifications of the invention, which are obvious to those skilled in the art and can be made on the basis of the above description, are not necessary or exhaustive for all embodiments, and are therefore within the scope of the invention.
Claims (10)
1. A CSP process-based special automobile high-strength steel plate with the pressure of more than 1000Mpa is characterized by comprising the following chemical components in percentage by mass: 0.20-0.25% of C, 0.25-0.3% of Si, 1.0-1.3% of Mn, 0.2-0.35% of Cr, 0.003-0.005% of B, 0.025-0.030% of Ti, 0.02-0.05% of Als, less than or equal to 0.010% of P, less than or equal to 0.005% of S, less than or equal to 0.005% of N, and the balance of Fe and other inevitable impurities; is prepared by a CSP process.
2. The CSP process-based special automobile high-strength steel plate of more than 1000MPa according to claim 1, wherein the metallographic structure of the special automobile high-strength steel plate comprises ferrite, bainite and martensite; wherein each tissue and the percentage thereof comprise: 5-20% of ferrite, 5-20% of bainite and 60-80% of martensite.
3. The CSP process-based special automobile high-strength steel plate with the pressure of more than 1000MPa according to claim 2, wherein the size of martensite is 8-12 μm.
4. The CSP process-based special automobile high-strength steel plate with the pressure of more than 1000MPa according to claim 1, wherein the yield strength of the special automobile high-strength steel plate is 700-970 MPa, the tensile strength of the special automobile high-strength steel plate is 1050-1300 MPa, and the elongation of the special automobile high-strength steel plate is more than or equal to 6%.
5. The CSP process-based preparation method of the special automobile high-strength steel plate with the pressure of more than 1000MPa according to any one of claims 1 to 4, which is characterized by mainly comprising the steps of smelting, refining, thin slab continuous casting, casting blank soaking, rolling, laminar cooling, reeling and flattening;
wherein the charging temperature of the casting blank is 850-950 ℃, and the discharging temperature is 1190-1210 ℃;
the rolling pass reduction distribution is as follows: 50-60% of the first pass, 50-60% of the second pass and 10-16% of the last pass; controlling the rolling speed to be 8-12 m/s; the finishing temperature is 850-890 ℃.
6. The manufacturing method according to claim 5, wherein in the thin slab continuous casting step, the superheat degree of the tundish steel is 15-30 ℃.
7. The preparation method according to claim 5, wherein the descaling process in the rolling process is descaling by high-pressure water before entering a rolling mill, and the pressure of the descaling water is 280-420 bar; and (3) removing scale by medium-pressure water between the F1 rolling mill and the F2 rolling mill, wherein the pressure of the scale removing water is 200-280 bar.
8. The preparation method of claim 5, wherein in the laminar cooling process, the temperature is rapidly cooled to 700-550 ℃ at a cooling rate of 80-120 ℃/s; air cooling for 3-8 s; then rapidly cooling to 230-280 ℃ at a cooling rate of 100-150 ℃/s.
9. The preparation method according to claim 5, wherein the coiling temperature is 230 to 280 ℃; and flattening the steel coil after the temperature of the steel coil is reduced to below 50 ℃.
10. The preparation method according to claim 5, wherein the thickness of the obtained finished strip steel is 0.8-2.0 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010892600.9A CN111996459B (en) | 2020-08-31 | 2020-08-31 | CSP (cast steel plate) process-based special high-strength steel plate for automobile with grade of more than 1000Mpa and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010892600.9A CN111996459B (en) | 2020-08-31 | 2020-08-31 | CSP (cast steel plate) process-based special high-strength steel plate for automobile with grade of more than 1000Mpa and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111996459A true CN111996459A (en) | 2020-11-27 |
| CN111996459B CN111996459B (en) | 2021-11-26 |
Family
ID=73465995
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010892600.9A Active CN111996459B (en) | 2020-08-31 | 2020-08-31 | CSP (cast steel plate) process-based special high-strength steel plate for automobile with grade of more than 1000Mpa and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111996459B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113774189A (en) * | 2021-08-25 | 2021-12-10 | 武汉钢铁有限公司 | Steelmaking method suitable for producing high-strength steel on CSP production line |
| CN114086084A (en) * | 2021-11-04 | 2022-02-25 | 湖南华菱涟钢特种新材料有限公司 | Hot-rolled dual-phase steel and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014194053A (en) * | 2013-03-29 | 2014-10-09 | Jfe Steel Corp | High strength hot rolled steel sheet and method for producing the same |
| CN106381451A (en) * | 2016-09-29 | 2017-02-08 | 马钢(集团)控股有限公司 | 1000MPa-level hot-rolled martensitic steel produced through CSP process and production method thereof |
| CN107557692A (en) * | 2017-08-23 | 2018-01-09 | 武汉钢铁有限公司 | 1000MPa levels analysis of producing hot rolled TRIP and manufacture method based on CSP flows |
| CN107641759A (en) * | 2017-09-13 | 2018-01-30 | 武汉钢铁有限公司 | Method based on CSP flows production Thin Specs hot forming steel |
| CN107904509A (en) * | 2017-10-19 | 2018-04-13 | 武汉钢铁有限公司 | A kind of Thin Specs 1180MPa grades of dual phase steels and its processing method |
-
2020
- 2020-08-31 CN CN202010892600.9A patent/CN111996459B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014194053A (en) * | 2013-03-29 | 2014-10-09 | Jfe Steel Corp | High strength hot rolled steel sheet and method for producing the same |
| CN106381451A (en) * | 2016-09-29 | 2017-02-08 | 马钢(集团)控股有限公司 | 1000MPa-level hot-rolled martensitic steel produced through CSP process and production method thereof |
| CN107557692A (en) * | 2017-08-23 | 2018-01-09 | 武汉钢铁有限公司 | 1000MPa levels analysis of producing hot rolled TRIP and manufacture method based on CSP flows |
| CN107641759A (en) * | 2017-09-13 | 2018-01-30 | 武汉钢铁有限公司 | Method based on CSP flows production Thin Specs hot forming steel |
| CN107904509A (en) * | 2017-10-19 | 2018-04-13 | 武汉钢铁有限公司 | A kind of Thin Specs 1180MPa grades of dual phase steels and its processing method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113774189A (en) * | 2021-08-25 | 2021-12-10 | 武汉钢铁有限公司 | Steelmaking method suitable for producing high-strength steel on CSP production line |
| CN114086084A (en) * | 2021-11-04 | 2022-02-25 | 湖南华菱涟钢特种新材料有限公司 | Hot-rolled dual-phase steel and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111996459B (en) | 2021-11-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107619993B (en) | Cold-rolled martensite steel plate with yield strength of 750MPa and manufacturing method thereof | |
| CN112048681B (en) | 980 MPa-grade high-formability cold-rolled DH steel and preparation method thereof | |
| CN111979489B (en) | 780 MPa-grade high-plasticity cold-rolled DH steel and preparation method thereof | |
| WO2018036347A1 (en) | Thermoforming steel rolled directly from medium thin slab and having tensile strength greater than or equal to 1500 mpa and production method | |
| WO2018036348A1 (en) | Thin thermoformed steel directly rolled using thin slabs and having tensile strength of ≥1500 mpa, and method for producing same | |
| CN111979490B (en) | High-ductility and high-formability cold-rolled DH590 steel and production method thereof | |
| WO2018036345A1 (en) | Hot forming steel directly rolled through medium and thin slab and having tensile strength larger than or equal to 1900 mpa and production method | |
| CN110453146B (en) | Cr alloyed steel without yield platform and preparation method thereof | |
| CN112095046B (en) | Ultrahigh-strength cold-rolled DH1180 steel and preparation method thereof | |
| WO2018036346A1 (en) | Thin thermoforming steel rolled directly from thin slab and having tensile strength greater than or equal to 1900 mpa and production method | |
| CN113403549B (en) | 1.2 GPa-grade fatigue-resistant high-formability ultrahigh-strength automobile steel and preparation method thereof | |
| CN113528944B (en) | 1000MPa easily-formed wear-resistant steel plate and preparation method thereof | |
| CN113832407B (en) | Preparation method of thick hot forming steel, hot rolled steel plate and hot forming steel | |
| CN110592348A (en) | Ultra-low carbon cold rolled steel performance grading control method | |
| CN111996459B (en) | CSP (cast steel plate) process-based special high-strength steel plate for automobile with grade of more than 1000Mpa and manufacturing method thereof | |
| CN114150227B (en) | High-toughness hot stamping steel rolled by medium and thin slabs with Rm more than or equal to 1500MPa and production method | |
| CN114214563B (en) | High-toughness hot stamping steel rolled by sheet billet with Rm more than or equal to 1500MPa and production method | |
| CN115094218A (en) | Production method of Q550-grade high-corrosion-resistance high-strength quenched and tempered steel plate for offshore structure | |
| CN113403541A (en) | 550 MPa-level low-alloy high-strength cold-rolled steel plate and production method thereof | |
| CN113025918A (en) | 800MPa steel based on multi-mode sheet billet continuous casting and rolling production line and production method thereof | |
| CN107513669A (en) | A kind of high-strength cold rolling square and rectangular pipe steel and its manufacture method | |
| CN116949357A (en) | 850 MPa-level environment-friendly pickling-free low-density high-strength steel and preparation method thereof | |
| CN112226679B (en) | Cold-rolled 980 MPa-grade martensitic steel and production method thereof | |
| CN109972023B (en) | Bainite steel with high product of strength and elongation and preparation method and application thereof | |
| CN113403540A (en) | 500 MPa-level low-alloy high-strength cold-rolled steel plate and production method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |