CN115612928A - High-strength steel based on CSP process and manufacturing method thereof - Google Patents
High-strength steel based on CSP process and manufacturing method thereof Download PDFInfo
- Publication number
- CN115612928A CN115612928A CN202211183801.7A CN202211183801A CN115612928A CN 115612928 A CN115612928 A CN 115612928A CN 202211183801 A CN202211183801 A CN 202211183801A CN 115612928 A CN115612928 A CN 115612928A
- Authority
- CN
- China
- Prior art keywords
- steel
- rolling
- equal
- cooling
- percent
- 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
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 59
- 239000010959 steel Substances 0.000 title claims abstract description 59
- 230000008569 process Effects 0.000 title claims abstract description 27
- 238000004519 manufacturing process Methods 0.000 title abstract description 17
- 238000003672 processing method Methods 0.000 title description 3
- 238000001816 cooling Methods 0.000 claims abstract description 39
- 238000000034 method Methods 0.000 claims abstract description 37
- 238000005096 rolling process Methods 0.000 claims abstract description 34
- 238000005266 casting Methods 0.000 claims abstract description 14
- 238000009749 continuous casting Methods 0.000 claims abstract description 14
- 238000002791 soaking Methods 0.000 claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 5
- 238000003723 Smelting Methods 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 238000007670 refining Methods 0.000 claims abstract description 4
- 229910001566 austenite Inorganic materials 0.000 claims description 18
- 229910000859 α-Fe Inorganic materials 0.000 claims description 18
- 229910001563 bainite Inorganic materials 0.000 claims description 7
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 3
- 230000009467 reduction Effects 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 238000005098 hot rolling Methods 0.000 abstract description 6
- 229910000885 Dual-phase steel Inorganic materials 0.000 abstract description 5
- 238000005097 cold rolling Methods 0.000 abstract description 5
- 238000005336 cracking Methods 0.000 abstract description 3
- 239000000463 material Substances 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 10
- 239000011572 manganese Substances 0.000 description 8
- 229910000734 martensite Inorganic materials 0.000 description 8
- 229910052799 carbon Inorganic materials 0.000 description 6
- 229910052748 manganese Inorganic materials 0.000 description 6
- 230000000717 retained effect Effects 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 239000010703 silicon Substances 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 230000006978 adaptation Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 230000000087 stabilizing effect Effects 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 229910001208 Crucible steel Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 229910052729 chemical element Inorganic materials 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
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
-
- 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
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
The invention discloses high-strength steel based on a CSP process and a manufacturing method thereof, wherein the high-strength steel comprises the following chemical components in percentage by mass: 0.14 to 0.18%, si:0.7 to 0.9%, mn: 2.0-2.5%, als 0.02-0.05%, P: less than or equal to 0.02%, S: less than or equal to 0.008 percent, N: less than or equal to 0.008 percent, and the balance of Fe and other inevitable impurities. The yield strength of the high-strength steel is 450-540 MPa, the tensile strength is 780-880 MPa, the hole expansion rate is more than or equal to 32%, and the elongation rate is more than or equal to 20%. The manufacturing method comprises the following steps: smelting, refining, thin slab continuous casting, casting blank soaking, rolling, laminar cooling, coiling and leveling. The hole expansion performance and the elongation of the high-strength steel are superior to those of the same-grade dual-phase steel, and the stamping cracking is effectively reduced. The manufacturing process adopts the CSP process, and compared with the conventional hot rolling and cold rolling, the production cost is reduced.
Description
Technical Field
The invention relates to the field of production of high-strength steel made of steel materials, in particular to high-strength steel based on a CSP (compact strip production) process and a manufacturing method thereof.
Background
In recent years, the development of the automobile industry requires lightweight and high reinforcement of automobile materials. High-strength steel is widely used for structural members of automobiles, in which dual-phase steel is generally used, but as the strength is increased, the plasticity and workability of the dual-phase steel are deteriorated, and particularly, properties such as flange formability and bending properties, which are determined by local elongation, are deteriorated. In order to solve the problem, high-strength steel strengthened by adopting the transformation induced plasticity effect draws wide attention, the retained austenite in the steel induces martensite transformation under plastic deformation, and a transformation strengthening mechanism and a plastic growth mechanism are introduced, so that the better unification of strength and plasticity is realized.
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 directly roll and produce thin steel plates with the thickness of 0.8-2.0 mm, and some high-strength steel which can only be produced by the conventional hot rolling and cold rolling process originally begins to be 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 effectively shortens the process flow and greatly reduces 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 CN107829027B discloses 780 Mpa-grade dual-phase steel based on CSP process and its processing method, the chemical element components and weight percentage are: 0.05 to 0.08 percent of C, 0.60 to 1.00 percent of Si, 1.40 to 1.80 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.004 percent of S, 0.30 to 0.70 percent of Cr, 0.020 to 0.060 percent of Als, and the balance of iron and inevitable impurities. The structure consists of 60 to 70 percent of ferrite and 30 to 40 percent of martensite. Because the structure and the mechanical property of ferrite and martensite are greatly different, compared with the high-strength steel with a bainite matrix, the cracking risk is high during punching.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide the high-strength steel for the automobile structural part, which has low cost, the yield strength of more than 450MPa and the tensile strength of more than 780MPa, and the manufacturing method thereof. The manufacturing process adopts the CSP process, and compared with the conventional hot rolling and cold rolling, the production cost is reduced.
In order to realize the purpose, the technical scheme of the invention is as follows:
on one hand, the invention provides high-strength steel based on the CSP process, which comprises the following chemical components in percentage by mass: 0.14 to 0.18%, si:0.7 to 0.9%, mn: 2.0-2.5%, als 0.02-0.05%, P: less than or equal to 0.02%, S: less than or equal to 0.008 percent, N: less than or equal to 0.008 percent and the balance of Fe and other inevitable impurities.
Preferably, the yield strength of the high-strength steel is 450-540 MPa, the tensile strength is 780-880 MPa, the hole expansion rate is greater than or equal to 32%, and the elongation rate is greater than or equal to 20%.
Preferably, the structure of the high-strength steel includes: ferrite with the content of 0-10 percent, residual austenite with the content of 5-8 percent, and carbide-free bainite as the rest.
In another aspect, the present invention provides a method of preparing high strength steel, comprising: smelting, refining, thin slab continuous casting, casting blank soaking, rolling, laminar cooling, coiling and leveling.
Preferably, in the thin slab continuous casting step, the superheat degree of the tundish molten steel is 15-30 ℃; the thickness of the casting blank is 70-75 mm, and the pulling speed is 4.0-4.8 m/s.
Preferably, the continuous thin slab casting blank is descaled before entering the furnace, and the descaling pressure is 15-30 bar.
Preferably, in the step of soaking the casting blank, the charging temperature of the casting blank is 820-1050 ℃, and the discharging temperature is 1190-1240 ℃.
Preferably, in the rolling step, the rolling pass reduction ratio is divided into: 50-60% of the first pass, 40-50% of the second pass and 8-12% of the last pass; controlling the rolling speed to be 7-12 m/s; the finishing temperature is 840-880 ℃; the descaling process in the rolling process adopts high-pressure water to descale before entering a rolling mill, and the pressure of the descaling water is 200-380 bar.
Preferably, the laminar cooling includes two cooling methods, one is: directly and quickly cooling the strip steel to a target coiling temperature after the strip steel is discharged from a rolling mill, wherein the cooling rate of quick cooling is not less than 40 ℃/s; the second method is as follows: and (3) after the strip steel is discharged from the rolling mill, air cooling is carried out for no more than 3s, the temperature is reduced to a two-phase region, a small amount of ferrite is generated, then the strip steel is rapidly cooled to a target coiling temperature, and the cooling rate of rapid cooling is not less than 40 ℃/s.
Preferably, the coiling temperature is 420-460 ℃; flattening the steel coil after the temperature of the steel coil is reduced to below 50 ℃, wherein the flattening force is controlled to be 160-200 tons; removing iron oxide scales by acid washing; the thickness of the obtained product is 1.0-2.0 mm.
Compared with the prior art, the invention has the following advantages:
the invention adopts low-alloy and low-cost design, and the content of main alloy elements is controlled as follows:
the function of C: carbon is the most basic strengthening element in steel and is also an austenite stabilizing element; the higher carbon content in the austenite is beneficial to improving the amount and stability of the residual austenite, thereby improving the mechanical property of the material; higher carbon content can reduce the weldability of the steel; therefore, the carbon content is controlled to be 0.14-0.18 percent.
The function of Si: the solubility of silicon in carbide is extremely low, the generation of the carbide can be effectively inhibited or delayed, the formation of carbon-rich austenite in the distribution process is facilitated, and the stability of retained austenite is improved; the higher silicon content is beneficial to obtaining more residual austenite, but the excessively high silicon content can reduce the high-temperature plasticity of the material and increase the defect incidence rate in the processes of steel making, continuous casting and hot rolling; therefore, the invention controls the silicon content to be 0.7-0.9%.
Function of Mn: manganese is an austenite stabilizing element; manganese can reduce the martensite generation starting point temperature, so that the content of the retained austenite is increased, and the stability of the retained austenite is improved; manganese also plays a solid solution strengthening role in steel; an excessively high manganese content can lead to excessively high hardenability of steel, which is not favorable for controlling the material structure; therefore, the invention controls the manganese content to be 2.0-2.5%.
The key process points are controlled as follows:
the finishing temperature is: the finishing temperature is more than 840 ℃, so that the structure is completely austenitic before cooling, and the phenomenon that excessive ferrite is generated in a two-phase region so as to greatly reduce the strength of the material is avoided; therefore, the finishing temperature is set to be 840 to 880 ℃ in the invention.
Laminar cooling: the laminar cooling process is divided into two types, one is that the strip steel is directly and quickly cooled to the coiling temperature after being taken out of the rolling mill, and the cooling rate is not less than 40 ℃/s. The structure generated at this time is carbide-free bainite and residual austenite, and has no ferrite; too low a cooling rate will result in precipitation of pearlite and reduced material properties. The other method is that the steel is slowly cooled to a ferrite and austenite two-phase region and then is quickly cooled to a target coiling temperature, and a small amount of ferrite is introduced in the slow cooling process to improve the plasticity of the material; the control is as follows: after the strip steel is discharged from the rolling mill, air cooling is carried out for no more than 3s, the temperature is reduced to a two-phase region (ferrite and austenite), a small amount of ferrite is generated, then the strip steel is rapidly cooled to a target coiling temperature, and the cooling rate is not less than 40 ℃/s; the process needs to avoid the air cooling time from being too long, and excessive ferrite is prevented from being generated, so that the strength of the material is greatly reduced.
Coiling temperature: the coiling temperature must be higher than the martensite formation starting point temperature and is within the bainite formation temperature range; too low coiling temperature can lead to the formation of a martensite matrix and a part of retained austenite structure, and the plasticity of the material can be greatly reduced; an excessively high coiling temperature will reduce the strength of the material; therefore, the coiling temperature is set to be 420-460 ℃ in the invention.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention provides high-strength steel for automobile structural parts, which has the yield strength of 450-540 MPa, the tensile strength of 780-880 MPa, the hole expansion rate of more than or equal to 32 percent and the elongation rate of more than or equal to 20 percent. Compared with dual-phase steel, because the matrix is carbide-free bainite, the difference of the structure and the mechanical property of the bainite and the ferrite is smaller than that of the ferrite and the martensite, the hole expansion ratio is improved, and the occurrence of stamping cracking can be reduced.
(2) 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.
(3) In the manufacturing process, a small amount of ferrite can be introduced by adjusting laminar cooling, so that the strength and the elongation of the material are adjusted to meet different material requirements.
Detailed Description
In order that those skilled in the art will better understand the technical solutions of the present invention, the following description of the preferred embodiments of the present invention is provided in connection with specific examples, which should not be construed as limiting the present patent.
The test methods or test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials, unless otherwise specified, are either commercially available from conventional sources or are prepared in conventional manners.
Table 1 shows the values of the chemical components and contents of examples 1 to 8 and comparative examples 9 to 12 of the present invention.
Table 2 shows some of the process parameters and sample properties of examples 1 to 8 according to the invention and comparative examples 9 to 12. In Table 2, reference numerals 1 to 8 denote examples, and reference numerals 9 to 12 denote comparative examples.
The invention provides a manufacturing method of high-strength steel for an automobile structural part, which has low cost, yield strength of more than 450MPa and tensile strength of more than 780MPa, and the CSP process flow comprises the following steps: smelting, refining, thin slab continuous casting, casting blank soaking, rolling, laminar cooling, coiling and leveling, which specifically comprises the following steps:
in the thin slab continuous casting step, the superheat degree of the tundish molten steel is 15-30 ℃; the thickness of the casting blank is 70-75 mm, and the pulling speed is 4.0-4.8 m/s. And (3) carrying out descaling treatment on the casting blank of the thin slab continuous casting before the casting blank enters a furnace, wherein the descaling pressure is 15-30 bar.
In the casting blank soaking step, the charging temperature of the casting blank is 820-1050 ℃, and the discharging temperature is 1190-1240 ℃.
In the rolling step, the rolling pass reduction ratio is distributed as follows: 50-60% of the first pass, 40-50% of the second pass and 8-12% of the last pass; controlling the rolling speed to be 7-12 m/s; the finishing temperature is 840 to 880 ℃; the descaling process in the rolling process is to adopt high-pressure water to descale before entering a rolling mill, and the pressure of the descaling water is 200-380 bar.
Laminar cooling comprises two cooling modes, wherein the first mode is as follows: directly and quickly cooling the strip steel to a target coiling temperature after the strip steel is discharged from a rolling mill, wherein the cooling rate of quick cooling is not less than 40 ℃/s; the second method is as follows: and (3) after the strip steel is discharged from the rolling mill, air cooling is carried out for no more than 3s, the temperature is reduced to a two-phase region, a small amount of ferrite is generated, then the strip steel is rapidly cooled to a target coiling temperature, and the cooling rate of rapid cooling is not less than 40 ℃/s.
The coiling temperature is 420-460 ℃; flattening the steel coil after the temperature of the steel coil is reduced to below 50 ℃, wherein the flattening force is controlled to be 160-200 tons; removing iron oxide scales by acid washing; the thickness of the obtained product is 1.0-2.0 mm.
TABLE 1 chemical composition of steels (wt.%)
| Composition (I) | Categories | C | Si | Mn | Als | P | S | N |
| A | Examples | 0.14 | 0.7 | 2.0 | 0.028 | 0.007 | 0.004 | 0.005 |
| B | Examples | 0.18 | 0.8 | 2.3 | 0.021 | 0.009 | 0.004 | 0.003 |
| C | Examples | 0.16 | 0.9 | 2.5 | 0.029 | 0.009 | 0.006 | 0.004 |
| D | Comparative example | 0.10 | 0.9 | 2.0 | 0.032 | 0.007 | 0.005 | 0.006 |
TABLE 2 examples and comparative examples part of the Process parameters and tensile Properties of the samples
As can be seen from tables 1 and 2, the yield strength of the high-strength steel prepared in the embodiments 1 to 8 of the invention is more than 450MPa, the tensile strength is more than 780MPa, the hole expansion rate is more than or equal to 32%, and the elongation rate is more than or equal to 20%, so as to meet different material requirements.
Comparing examples 1 to 8 and comparative example 9, when the C content is too low, sufficient retained austenite cannot be generated and the properties of the material are degraded. Comparing example 3 and comparative example 10, when the finish rolling temperature exceeds 880 ℃, the final structure is not as fine as the sample structure at the lower finish rolling temperature due to austenite grain coarsening, and the performance is degraded. In comparative examples 1 to 3 and comparative example 11, martensite was formed when the coiling temperature was lowered to 420 ℃ or lower, and the strength was greatly increased, but the formability was deteriorated. Comparing example 4 with comparative example 12, when the air cooling time was 5s, excessive ferrite was generated during cooling, and the yield strength was reduced to 450Mpa or less.
The above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.
Claims (10)
1. The high-strength steel based on the CSP process is characterized by comprising the following chemical components in percentage by mass: 0.14 to 0.18%, si:0.7 to 0.9%, mn: 2.0-2.5%, als 0.02-0.05%, P: less than or equal to 0.02 percent, S: less than or equal to 0.008 percent, N: less than or equal to 0.008 percent, and the balance of Fe and other inevitable impurities.
2. The high-strength steel based on the CSP process as claimed in claim 1, wherein the yield strength of the high-strength steel is 450-540 MPa, the tensile strength is 780-880 MPa, the hole expansion rate is greater than or equal to 32%, and the elongation rate is greater than or equal to 20%.
3. A high strength steel based on CSP process according to claim 1 characterized by that its structure comprises: ferrite with the content of 0-10 percent, residual austenite with the content of 5-8 percent, and carbide-free bainite as the rest.
4. A method of producing a high strength steel according to any one of claims 1 to 3, comprising: smelting, refining, thin slab continuous casting, casting blank soaking, rolling, laminar cooling, coiling and leveling.
5. The method of claim 4, wherein in the thin slab continuous casting step, the superheat degree of the tundish steel is 15-30 ℃; the thickness of the casting blank is 70-75 mm, and the pulling speed is 4.0-4.8 m/s.
6. A method according to claim 4, characterized in that the slab is descaled before being fed into the furnace at a pressure of 15 to 30bar.
7. The method according to claim 4, wherein in the billet soaking step, the billet is charged at 820-1050 ℃ and discharged at 1190-1240 ℃.
8. The method of claim 4, wherein in the rolling step, the rolling pass reduction ratios are assigned as: 50-60% of the first pass, 40-50% of the second pass and 8-12% of the last pass; controlling the rolling speed to be 7-12 m/s; the finishing temperature is 840-880 ℃; the descaling process in the rolling process adopts high-pressure water to descale before entering a rolling mill, and the pressure of the descaling water is 200-380 bar.
9. The method of claim 4, wherein laminar cooling comprises two cooling modes, one being: directly and quickly cooling the strip steel to a target coiling temperature after the strip steel is discharged from a rolling mill, wherein the cooling rate of quick cooling is not less than 40 ℃/s; the second method is as follows: and (3) after the strip steel is discharged from the rolling mill, air cooling is carried out for no more than 3s, the temperature is reduced to a two-phase region, a small amount of ferrite is generated, then the strip steel is rapidly cooled to a target coiling temperature, and the cooling rate of rapid cooling is not less than 40 ℃/s.
10. The method of claim 4, wherein the coiling temperature is 420 to 460 ℃; flattening the steel coil after the temperature of the steel coil is reduced to below 50 ℃, wherein the flattening force is controlled to be 160-200 tons; removing iron oxide scales by acid washing; the thickness of the obtained product is 1.0-2.0 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211183801.7A CN115612928B (en) | 2022-09-27 | 2022-09-27 | High-strength steel based on CSP process and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211183801.7A CN115612928B (en) | 2022-09-27 | 2022-09-27 | High-strength steel based on CSP process and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115612928A true CN115612928A (en) | 2023-01-17 |
| CN115612928B CN115612928B (en) | 2024-03-15 |
Family
ID=84861289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211183801.7A Active CN115612928B (en) | 2022-09-27 | 2022-09-27 | High-strength steel based on CSP process and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115612928B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004225105A (en) * | 2003-01-23 | 2004-08-12 | Nippon Steel Corp | Thin steel sheet for working having excellent deep drawability, and production method therefor |
| JP2007070660A (en) * | 2005-09-05 | 2007-03-22 | Nippon Steel Corp | High strength thin steel sheet having excellent formability, and method for producing the same |
| CN102965569A (en) * | 2012-11-26 | 2013-03-13 | 宝山钢铁股份有限公司 | Hot rolling phase change inducing plastic steel plate and manufacturing method thereof |
| CN111684084A (en) * | 2018-02-07 | 2020-09-18 | 塔塔钢铁荷兰科技有限责任公司 | High-strength hot-rolled or cold-rolled and annealed steel and method for the production thereof |
-
2022
- 2022-09-27 CN CN202211183801.7A patent/CN115612928B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004225105A (en) * | 2003-01-23 | 2004-08-12 | Nippon Steel Corp | Thin steel sheet for working having excellent deep drawability, and production method therefor |
| JP2007070660A (en) * | 2005-09-05 | 2007-03-22 | Nippon Steel Corp | High strength thin steel sheet having excellent formability, and method for producing the same |
| CN102965569A (en) * | 2012-11-26 | 2013-03-13 | 宝山钢铁股份有限公司 | Hot rolling phase change inducing plastic steel plate and manufacturing method thereof |
| CN111684084A (en) * | 2018-02-07 | 2020-09-18 | 塔塔钢铁荷兰科技有限责任公司 | High-strength hot-rolled or cold-rolled and annealed steel and method for the production thereof |
Non-Patent Citations (1)
| Title |
|---|
| 杨光辉等编著: "薄板坯连铸连轧和薄带连铸关键工艺技术", 冶金工业出版社, pages: 135 - 136 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115612928B (en) | 2024-03-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107619993B (en) | Cold-rolled martensite steel plate with yield strength of 750MPa and manufacturing method thereof | |
| CN112095046B (en) | Ultrahigh-strength cold-rolled DH1180 steel and preparation method thereof | |
| CN110295320B (en) | Large-wall-thickness X52MS acid-resistant pipeline steel plate produced by LF-RH refining process and manufacturing method thereof | |
| CN112048681A (en) | 980 MPa-grade high-formability cold-rolled DH steel and preparation method thereof | |
| CN111979489A (en) | 780 MPa-grade high-plasticity cold-rolled DH steel and preparation method thereof | |
| CN110777296B (en) | Ultra-thick X52 pipeline steel hot-rolled coil and production method thereof | |
| CN111979490A (en) | High-ductility and high-formability cold-rolled DH590 steel and production method thereof | |
| CN105937011B (en) | Low yield strength cold rolling high strength steel plate and preparation method thereof | |
| CN113528944B (en) | 1000MPa easily-formed wear-resistant steel plate and preparation method thereof | |
| CN112831731A (en) | Online quenching complex phase structure hot-rolled wear-resistant steel and preparation method thereof | |
| CN112226673A (en) | Hot rolled steel plate with 650 MPa-grade tensile strength and manufacturing method thereof | |
| CN114015951A (en) | Hot-rolled light high-strength steel and preparation method thereof | |
| 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 | |
| CN110983180B (en) | Hot-rolled high-strength steel and preparation method and application thereof | |
| CN113061797A (en) | Improved production method of QStE420TM hot-rolled steel plate | |
| CN112410671A (en) | Production method for producing steel for rim by adopting complex phase structure | |
| CN116949357A (en) | 850 MPa-level environment-friendly pickling-free low-density high-strength steel and preparation method thereof | |
| CN113802054A (en) | Hot rolled steel plate with yield strength of 420MPa and manufacturing method thereof | |
| CN111321342A (en) | One-steel multi-stage cold-rolled low-alloy high-strength steel and manufacturing method thereof | |
| CN112575267A (en) | High-hole-expansion complex phase steel and manufacturing method thereof | |
| CN112410676B (en) | Hot-rolled low-carbon steel and production method thereof | |
| CN114717478A (en) | Light high-strength steel and production method thereof | |
| CN115612928B (en) | High-strength steel based on CSP process and manufacturing method thereof | |
| CN112962022A (en) | High-drawing high-reaming 1200 MPa-grade cold-rolled strip steel and production method thereof | |
| CN111926261A (en) | High-strength weathering steel with yield strength of 550MPa 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 |