CN116815070A - Low-cost Ti microalloyed 600 MPa-level hot rolled steel strip and preparation method and application thereof - Google Patents
Low-cost Ti microalloyed 600 MPa-level hot rolled steel strip and preparation method and application thereof Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 88
- 239000010959 steel Substances 0.000 title claims abstract description 88
- 238000002360 preparation method Methods 0.000 title abstract description 7
- 238000001816 cooling Methods 0.000 claims abstract description 72
- 238000005096 rolling process Methods 0.000 claims abstract description 45
- 238000004519 manufacturing process Methods 0.000 claims abstract description 15
- 238000000034 method Methods 0.000 claims abstract description 14
- 230000008569 process Effects 0.000 claims abstract description 9
- 239000012535 impurity Substances 0.000 claims abstract description 7
- 239000000126 substance Substances 0.000 claims abstract description 7
- 229910000859 α-Fe Inorganic materials 0.000 claims description 20
- 239000002244 precipitate Substances 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 11
- 229910001562 pearlite Inorganic materials 0.000 claims description 11
- 238000007670 refining Methods 0.000 claims description 8
- 230000001186 cumulative effect Effects 0.000 claims description 6
- 230000009467 reduction Effects 0.000 claims description 6
- 238000005452 bending Methods 0.000 claims description 4
- 238000003723 Smelting Methods 0.000 claims description 3
- 238000009749 continuous casting Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 238000005728 strengthening Methods 0.000 abstract description 13
- 238000001556 precipitation Methods 0.000 abstract description 9
- 229910000742 Microalloyed steel Inorganic materials 0.000 abstract description 5
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 3
- 230000008859 change Effects 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 7
- 238000013461 design Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000003917 TEM image Methods 0.000 description 4
- 238000004321 preservation Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 229910000885 Dual-phase steel Inorganic materials 0.000 description 3
- 229910001566 austenite Inorganic materials 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 229910000734 martensite Inorganic materials 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 239000011701 zinc Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 241001163841 Albugo ipomoeae-panduratae Species 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000033764 rhythmic process Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Classifications
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- 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
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Abstract
The invention discloses a low-cost Ti microalloyed 600 MPa-level hot rolled steel strip, a preparation method and application thereof, wherein the hot rolled steel strip comprises the following chemical components in percentage by weight: less than or equal to 0.10 percent; si:0.10 to 0.20 percent; mn: less than or equal to 0.80; p: less than or equal to 0.015 percent; s: less than or equal to 0.008 percent; ti:0.07 to 0.09 percent; als:0.015 to 0.035 percent; the balance of Fe and unavoidable impurities, the invention realizes the precipitation strengthening of Ti microalloyed steel by adopting an ultrafast cooling-air cooling-ultrafast cooling three-section control cooling process after rolling and takes account of low-temperature coiling phase change strengthening, so as to obtain 600MPa grade Ti microalloyed high-strength steel with low cost and excellent comprehensive performance, which is used for manufacturing a photovoltaic bracket, can obviously reduce cost, improve strength, realize light weight and carbon emission, and realize green manufacturing of products.
Description
Technical Field
The invention belongs to the technical field of hot-rolled high-strength steel production, and particularly relates to a low-cost Ti microalloyed 600 MPa-grade hot-rolled steel strip, and a preparation method and application thereof.
Background
The photovoltaic support is a special support designed for placing, installing and fixing the solar panel in the solar photovoltaic power generation system, and the structure is required to be firm and reliable, strong in weather resistance and capable of bearing atmospheric corrosion, wind load and other external effects. Driven by policies such as environmental protection, energy saving and the like at home and abroad, the development of novel support materials such as clean energy, high strength and light weight, thinning of zinc layers, free coating of weather-resistant steel and the like has become a necessary trend of development of the steel for the photovoltaic support, and the requirements on the comprehensive performance of the steel for the photovoltaic support are higher and higher.
In recent years, ti microalloyed hot rolled high strength steel is widely applied in the fields of photovoltaic brackets, automobiles, buildings, railway vehicles and the like, and becomes an important raw material for realizing light weight design and manufacturing in related industries. The Ti element has excellent fine crystal strengthening and precipitation strengthening effects, is mainly precipitated in a form of fine Ti (C, N), and can remarkably improve the comprehensive performance of steel. The process window of the carbonitride precipitated phase of Ti, especially interphase precipitated phase, is narrow, and the refining control in the rolling process has certain difficulty, so how to obtain nano precipitated with more volume fraction in the subsequent cooling ferrite is very important for improving the strength of steel and reducing the cost.
At present, the domestic steel for the photovoltaic bracket mainly adopts Q235/Q345B grade high-strength steel and batch hot dip galvanization to realize firm and reliable structure and strong weather resistance, and is designed and optimized for the structure, the components, the nodes, the materials and the like of the photovoltaic bracket, 600MPa grade high-strength steel is adopted to replace Q235/Q345B, and the weight reduction rate after checking is 25-35%. Therefore, developing the steel for the photovoltaic bracket with the grade of 600MPa and above has important significance for promoting the light weight of the photovoltaic industry, reducing the carbon emission, achieving clean energy and the like.
The Chinese patent CN 108277441A discloses a 600 MPa-level Ti microalloyed hot-rolled dual-phase steel plate and a preparation method thereof, and specifically discloses a dual-phase steel plate which comprises the following chemical components in percentage by mass: c:0.04 to 0.08 percent, si:0.05 to 0.15 percent, mn:0.90 to 1.10 percent, S: less than or equal to 0.013 percent, P: less than or equal to 0.020%, als:0.02 to 0.05 percent, ti:0.03 to 0.05 percent, and the balance of Fe and unavoidable impurities. The preparation method of the dual-phase steel plate comprises the following steps: 1) Heating the billet to 1200-1240 ℃ and preserving heat for 1.5-2.5 h; 2) Rough rolling is carried out on the heated steel billet; 3) Finish rolling is carried out on the intermediate blank; 4) And carrying out water cooling, air cooling and water cooling three-section cooling on the plate. The chemical components in the patent adopt 0.9-1.1% Mn, the cost is high, the plate strip is subjected to water cooling, air cooling and water cooling three-section cooling, the target structure is a ferrite and martensite dual-phase structure, and the yield strength of the product is only 362-395 MPa, and the strength is low.
The Chinese patent CN 110616301A discloses a production method for improving the precipitation strengthening effect of Ti microalloyed hot rolled high-strength steel on line, which specifically discloses: casting the molten steel added with the microalloy element Ti to obtain a casting blank or an ingot, heating, performing rough rolling, finish rolling, laminar cooling and coiling to obtain a hot rolled coil, unloading, covering a heat preservation cover on line, moving into a steel coil warehouse along with a conveying chain, removing the heat preservation cover after the on-line heat preservation time is reached, and performing air cooling to room temperature. The process needs to add a heat preservation cover, has more steps and long flow time, and obviously increases the cost.
It can be seen that research results in the prior art on Ti microalloyed hot rolled high strength steel mainly focus on how to realize ferrite+bainitic structure or ferrite+martensitic dual phase high strength steel so as to reduce cost, but formability of these steels is relatively poor; or extra equipment such as an insulation cover is added to promote precipitation strengthening, but the steps are more, the flow time is long, and the cost is obviously increased.
Disclosure of Invention
In order to solve the technical problems, the invention provides a low-cost Ti microalloyed 600MPa grade hot rolled steel strip and a preparation method thereof, wherein the precipitation strengthening of the Ti microalloyed steel is realized by adopting an ultrafast cooling-air cooling-ultrafast cooling three-section control cooling process after rolling through reasonable component design and process optimization, and the 600MPa grade Ti microalloyed high-strength steel with low cost and excellent comprehensive performance is obtained.
The invention also provides application of the low-cost Ti microalloyed 600MPa grade hot rolled steel strip as steel for the photovoltaic bracket, and the Ti microalloyed steel is mainly used for manufacturing the photovoltaic bracket, can obviously reduce cost and strength, realize light weight, reduce carbon emission, really realize clean energy and realize green manufacturing of products.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip comprises the following chemical components in percentage by weight: less than or equal to 0.10 percent; si:0.10 to 0.20 percent; mn: less than or equal to 0.80 percent; p: less than or equal to 0.015 percent; s: less than or equal to 0.008 percent; ti:0.07 to 0.09 percent; als:0.015 to 0.035 percent; the balance of Fe and unavoidable impurities.
The invention relates to a low-cost Ti microalloying 600 MPa-grade hot rolled steel strip, which comprises the following alloy elements in percentage by mass: the chemical composition of the invention adopts the design concept of low C+proper Si+proper Mn+high Ti content, and the content of impurity elements such as P, S is strictly controlled. C: c is not more than 0.10 percent and plays a very important role in improving the strength of steel as a basic element in the steel, a certain content of C is required to be ensured in order to obtain higher strength, but the welding performance is deteriorated due to the excessively high content of C, and meanwhile, the required amount of ferrite is difficult to obtain in the cooling process after hot rolling, so that the shaping of the steel is poor; in addition, the low-C design is beneficial to hot charging and hot delivery of steel mills, the production rhythm is improved, the cost is reduced, and the environmental pollution is reduced. Si:0.10 to 0.20 percent, the addition of a proper amount of Si element not only can play a solid solution strengthening effect to increase the strength of steel, but also is beneficial to preventing wet rust or white rust from being stored to improve the quality of a subsequent zinc plating layer and reduce the phenomenon of plating leakage. Mn: less than or equal to 0.80 percent, mn can obviously improve the strength, but the Mn content is too high, so that center segregation is easy to cause, the uniform distribution of the structure and the performance of the steel strip is not facilitated, and ferrite with the required quantity is not easy to form after rolling, thereby adversely affecting the forming performance of the steel; in addition, the increase of Mn content also correspondingly increases alloy cost, which is unfavorable for low-cost design. P, S as an impurity element adversely affects the properties of steel such as forming and welding, and the content should be strictly controlled so that the lower the content is, the better the content is, and therefore, P, S is controlled to be 0.015% or less and 0.008% or less. Al is a main deoxidizing element in steel, and the O content in steel can be obviously reduced, so that the content of Al is controlled to be 0.015-0.035%. Ti: 0.07-0.09%, ti mainly plays three roles, namely, ti is combined with N element to form TiN to play a role in nitrogen fixation, austenite grains are refined, ferrite and pearlite which are finally transformed are refined, and nano-level Ti precipitates are uniformly and largely separated out in an air cooling stage of an ultra-fast cooling-air cooling-ultra-fast cooling three-stage control cooling process, so that the strength of a material is fully improved, the precipitation strengthening of Ti micro-alloyed steel is realized, the low-temperature coiling phase change strengthening is compatible, and the material is guaranteed to have excellent comprehensive performance on the premise of low cost.
The metallographic structure of the low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip is a precipitate of ferrite, pearlite and Ti.
In the metallographic structure of the low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip, the volume of ferrite is 70% -80%, the volume of pearlite is 19% -29%, and the volume of precipitate is more than or equal to 0.4%.
The yield strength of the low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip is more than or equal to 600MPa, the tensile strength is more than or equal to 680MPa, the elongation A50 is more than or equal to 25%, the cold bending performance is 180 degrees, and D=a is qualified, so that the low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip has higher strength and better formability.
The invention provides a production method of a low-cost Ti microalloyed 600 MPa-level hot rolled steel strip, which comprises the following steps: converter smelting, refining, continuous casting, heating, rolling, cooling and coiling.
In the cooling step, an ultrafast cooling-air cooling-ultrafast cooling three-stage control cooling process is adopted, the section I water cooling of the rolled steel plate is cooled to 640-660 ℃ by adopting ultrafast cooling at a cooling speed of more than or equal to 100 ℃/s for air cooling, the section II air cooling is 15-25 s, the section III water cooling is cooled to 570-610 ℃ by adopting ultrafast cooling at a cooling speed of more than or equal to 100 ℃/s for coiling, and the steel plate is cooled to room temperature after coiling.
The cooling speed of the water cooling of the section I is preferably 100-150 ℃/s; the cooling rate of the III-stage water cooling is preferably 100-150 ℃/s.
N in the molten steel component at the refining end point is less than or equal to 50ppm.
In the heating step, the heating temperature is 1250+/-20 ℃, and the total furnace time is more than or equal to 160 minutes.
In the rolling step, a two-stage control rolling process is adopted, the cumulative rolling reduction of rough rolling is more than or equal to 70%, and the cumulative rolling reduction of finish rolling is more than or equal to 80%; the initial rolling temperature of rough rolling is 1130-1180 ℃, and the final rolling temperature of finish rolling is 860-900 ℃; convexity control 40+ -20 μm, wedge control 0+ -20 μm, flatness control-50I to +50I.
In the production method of the low-cost Ti microalloying 600 MPa-level hot rolled steel strip, in the hot rolling process design, the final rolling temperature is controlled to be 860-900 ℃, and the lower final rolling temperature is favorable for refining the original austenite grain size and rapidly entering a ferrite transformation zone after final rolling to obtain a ferrite structure. After rolling, adopting three-stage control cooling technology of ultra-fast cooling-air cooling-ultra-fast cooling: the section I water cooling of the rolled steel plate is cooled to 640-660 ℃ by adopting ultra-fast cooling at a cooling speed of more than or equal to 100 ℃/s for air cooling, and the purpose is to enable the material to rapidly enter a ferrite transformation area and refine ferrite grains, and a sufficient time is reserved for the subsequent air cooling by adopting an ultra-fast cooling technology; the step II of air cooling for 15-25 s aims at homogenizing the temperature of the steel plate, promoting the uniform and sufficient precipitation of nano-grade Ti precipitates and achieving the aim of improving the precipitation strengthening effect; the III-stage water cooling adopts ultra-fast cooling to cool to 570-610 ℃ at a cooling speed of more than or equal to 100 ℃/s for coiling, and air cooling is carried out to room temperature after coiling, so that an unconverted austenite structure is rapidly converted into a pearlite structure, a steel plate structure is ferrite, pearlite and a large amount of Ti precipitates, the Ti microalloyed steel precipitation strengthening is realized, the low-temperature coiling phase change strengthening is compatible, and the material is guaranteed to have excellent comprehensive performance on the premise of low cost.
The microstructure of the hot rolled steel plate produced by adopting the technical scheme of the invention is ferrite, pearlite and a large amount of Ti precipitates, wherein the ferrite volume is 70% -80%, the pearlite volume is 19% -29%, the precipitate volume is more than or equal to 0.4%, the yield strength of the product is more than or equal to 600MPa, the tensile strength is more than or equal to 680MPa, the elongation A50 is more than or equal to 25%, the cold bending performance is 180 degrees, and D=a is qualified, so that the hot rolled steel plate has higher strength and better forming performance.
Drawings
FIG. 1 is a metallographic structure diagram of a hot rolled steel strip in example 1;
FIG. 2 is a TEM image of the hot rolled steel strip of example 1, from which a large number of Ti precipitates can be seen;
FIG. 3 is a metallographic structure of a hot rolled steel strip in example 2;
FIG. 4 is a TEM image of the hot rolled steel strip in example 2, from which a large number of Ti precipitates can be seen;
FIG. 5 is a metallographic structure of a hot rolled steel strip in example 3;
FIG. 6 is a TEM image of the hot rolled steel strip in example 3, from which a large number of Ti precipitates can be seen;
FIG. 7 is a metallographic structure of a hot rolled steel strip in example 4;
FIG. 8 is a TEM image of the hot rolled steel strip in example 4, from which a large number of Ti precipitates can be seen;
FIG. 9 is a metallographic structure diagram of a hot rolled steel strip in comparative example 1;
FIG. 10 is a metallographic structure diagram of a hot rolled steel strip in comparative example 2.
Detailed Description
The invention provides a low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip, which comprises the following chemical components in percentage by weight: less than or equal to 0.10 percent; si:0.10 to 0.20 percent; mn: less than or equal to 0.80 percent; p: less than or equal to 0.015 percent; s: less than or equal to 0.008 percent; ti:0.07 to 0.09 percent; als:0.015 to 0.035 percent; the balance of Fe and unavoidable impurities.
The production method of the low-cost Ti microalloyed 600 MPa-level hot rolled steel strip comprises the following steps: converter smelting, refining, continuous casting, heating, rolling, cooling and coiling.
N in the molten steel component at the refining end point is less than or equal to 50ppm.
In the heating step, the heating temperature is 1250+/-20 ℃, and the total furnace time is more than or equal to 160 minutes.
In the rolling step, a two-stage control rolling process is adopted, the cumulative rolling reduction of rough rolling is more than or equal to 70%, and the cumulative rolling reduction of finish rolling is more than or equal to 80%; the initial rolling temperature of rough rolling is 1130-1180 ℃, and the final rolling temperature of finish rolling is 860-900 ℃; convexity control 40+ -20 μm, wedge control 0+ -20 μm, flatness control-50I to +50I.
In the cooling step, an ultrafast cooling-air cooling-ultrafast cooling three-stage control cooling process is adopted, the section I water cooling of the rolled steel plate is cooled to 640-660 ℃ by adopting ultrafast cooling at a cooling speed of more than or equal to 100 ℃/s for air cooling, the section II air cooling is 15-25 s, the section III water cooling is cooled to 570-610 ℃ by adopting ultrafast cooling at a cooling speed of more than or equal to 100 ℃/s for coiling, and the steel plate is cooled to room temperature after coiling.
The present invention will be described in detail with reference to examples.
The compositions and weight percentages of the hot rolled steel strips in each of the examples and comparative examples are shown in Table 1.
TABLE 1
| Numbering device | C | Si | Mn | P | S | Als | Ti | N |
| Example 1 | 0.077 | 0.156 | 0.678 | 0.0125 | 0.0041 | 0.0323 | 0.0853 | 0.0017 |
| Example 2 | 0.082 | 0.163 | 0.689 | 0.0098 | 0.0010 | 0.0331 | 0.0833 | 0.0020 |
| Example 3 | 0.076 | 0.147 | 0.699 | 0.0138 | 0.0014 | 0.0305 | 0.0819 | 0.0019 |
| Example 4 | 0.081 | 0.155 | 0.653 | 0.0098 | 0.0023 | 0.0275 | 0.0767 | 0.0021 |
| Comparative example 1 | 0.171 | 0.202 | 1.205 | 0.0152 | 0.0035 | 0.0401 | 0.1071 | 0.0037 |
| Comparative example 2 | 0.080 | 0.164 | 0.704 | 0.0146 | 0.0027 | 0.0299 | 0.0912 | 0.0017 |
The production process parameters of the hot rolled steel strip in each of the examples and comparative examples are shown in table 2.
TABLE 2
The properties of the hot rolled steel strips in each of the examples and comparative examples are shown in Table 3.
TABLE 3 Table 3
As can be seen from Table 3, the hot rolled steel sheet produced by the method of the present invention has a microstructure of ferrite, pearlite and a large amount of Ti precipitates, wherein the ferrite volume is 70% -80%, the pearlite volume is 19% -29%, the precipitate volume is not less than 0.4%, the yield strength of the product is not less than 600MPa, the tensile strength is not less than 680MPa, the elongation A50 is not less than 25%, the cold bending property is 180 DEG, and D=a is qualified, and the hot rolled steel sheet has high strength and good formability.
The foregoing detailed description of a low cost Ti microalloyed 600MPa grade hot rolled steel strip and method of making and using the same, with reference to examples, is illustrative and not limiting, and several examples can be listed in the scope of the disclosure, thus variations and modifications without departing from the general inventive concept are intended to be within the scope of the disclosure.
Claims (10)
1. A low-cost Ti microalloyed 600 MPa-grade hot rolled steel strip is characterized by comprising the following chemical components in percentage by weight: less than or equal to 0.10 percent; si:0.10 to 0.20 percent; mn: less than or equal to 0.80 percent; p: less than or equal to 0.015 percent; s:
less than or equal to 0.008 percent; ti:0.07 to 0.09 percent; als:0.015 to 0.035 percent; the balance of Fe and unavoidable impurities.
2. The low cost Ti micro alloyed 600MPa grade hot rolled steel strip of claim 1 wherein the metallographic structure of the low cost Ti micro alloyed 600MPa grade hot rolled steel strip is ferrite + pearlite + Ti precipitates.
3. The low-cost Ti micro-alloyed 600 MPa-grade hot-rolled steel strip of claim 2, wherein the low-cost Ti micro-alloyed 600 MPa-grade hot-rolled steel strip has a metallographic structure with ferrite volume of 70% -80%, pearlite volume of 19% -29% and precipitate volume of 0.4% or more.
4. A low cost Ti micro alloyed 600MPa grade hot rolled steel strip according to any one of claims 1-3 wherein the low cost Ti micro alloyed 600MPa grade hot rolled steel strip has a yield strength not less than 600MPa, a tensile strength not less than 680MPa, an elongation a50 not less than 25%, cold bending properties 180 °, d=a.
5. The method for producing a low cost Ti micro-alloyed 600MPa grade hot rolled steel strip according to any one of claims 1-4, wherein the method comprises the steps of: converter smelting, refining, continuous casting, heating, rolling, cooling and coiling.
6. The production method according to claim 5, wherein in the cooling step, an ultrafast cooling-air cooling-ultrafast cooling three-stage controlled cooling process is adopted, the section I water cooling of the rolled steel plate is cooled to 640-660 ℃ by ultrafast cooling at a cooling speed of more than or equal to 100 ℃/s for air cooling, the section II air cooling is 15-25 s, the section III water cooling is cooled to 570-610 ℃ by ultrafast cooling at a cooling speed of more than or equal to 100 ℃/s for coiling, and the steel plate is cooled to room temperature after coiling.
7. The method according to claim 5, wherein N in the molten steel composition at the refining end is 50ppm or less.
8. The method according to claim 5, wherein in the heating step, the heating temperature is 1250.+ -. 20 ℃ and the total furnace time is not less than 160min.
9. The method according to claim 5, wherein in the rolling step, a two-stage controlled rolling process is adopted, the cumulative rolling reduction of rough rolling is not less than 70%, and the cumulative rolling reduction of finish rolling is not less than 80%; the initial rolling temperature of rough rolling is 1130-1180 ℃, and the final rolling temperature of finish rolling is 860-900 ℃; convexity control 40+ -20 μm, wedge control 0+ -20 μm, flatness control-50I to +50I.
10. Use of the low cost Ti micro-alloyed 600MPa grade hot rolled steel strip of any one of claims 1-4 as steel for photovoltaic brackets.
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| CN202310703396.5A CN116815070A (en) | 2023-06-14 | 2023-06-14 | Low-cost Ti microalloyed 600 MPa-level hot rolled steel strip and preparation method and application thereof |
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| CN202310703396.5A CN116815070A (en) | 2023-06-14 | 2023-06-14 | Low-cost Ti microalloyed 600 MPa-level hot rolled steel strip and preparation method and application thereof |
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| CN116815070A true CN116815070A (en) | 2023-09-29 |
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