CN114438411A - Weather-resistant steel for photovoltaic support and production method thereof - Google Patents
Weather-resistant steel for photovoltaic support and production method thereof Download PDFInfo
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 32
- 239000010959 steel Substances 0.000 title claims abstract description 32
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 16
- 229910000870 Weathering steel Inorganic materials 0.000 claims abstract description 25
- 239000012535 impurity Substances 0.000 claims abstract description 9
- 238000003723 Smelting Methods 0.000 claims abstract description 7
- 238000005096 rolling process Methods 0.000 claims description 27
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 22
- 238000001816 cooling Methods 0.000 claims description 14
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 10
- 239000002893 slag Substances 0.000 claims description 10
- 238000010583 slow cooling Methods 0.000 claims description 10
- 230000007797 corrosion Effects 0.000 claims description 9
- 238000005260 corrosion Methods 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- 238000009849 vacuum degassing Methods 0.000 claims description 9
- 229910001566 austenite Inorganic materials 0.000 claims description 8
- 238000001953 recrystallisation Methods 0.000 claims description 8
- 238000007670 refining Methods 0.000 claims description 8
- 239000000956 alloy Substances 0.000 claims description 7
- 238000003756 stirring Methods 0.000 claims description 7
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical group [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052717 sulfur Inorganic materials 0.000 claims description 6
- 239000011593 sulfur Substances 0.000 claims description 6
- 229910052786 argon Inorganic materials 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 5
- 238000005266 casting Methods 0.000 claims description 4
- 230000014759 maintenance of location Effects 0.000 claims description 4
- 230000035945 sensitivity Effects 0.000 claims description 4
- 239000006104 solid solution Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 4
- 238000007667 floating Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 description 8
- 229910000859 α-Fe Inorganic materials 0.000 description 7
- 238000010248 power generation Methods 0.000 description 5
- 229910001563 bainite Inorganic materials 0.000 description 3
- 229910001562 pearlite Inorganic materials 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 230000001737 promoting effect Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000012958 reprocessing Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 230000006911 nucleation Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/072—Treatment with gases
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
-
- 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
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- 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
- C22C38/001—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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- 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
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- 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
- C21D2211/009—Pearlite
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- Heat Treatment Of Steel (AREA)
Abstract
The invention relates to the technical field of steel smelting, and discloses weathering steel for a photovoltaic bracket and a production method thereof, aiming at the problem that the comprehensive mechanical property of the weathering steel applied to the photovoltaic bracket in the prior art is not easy to match with the applicability of the steel for the photovoltaic bracket, the following scheme is proposed, and the weathering steel comprises the following components in percentage by mass: c: 0.030-0.070%; si: 0.20-0.50%; mn: 0.3-1.20%; p: less than or equal to 0.020%; s: less than or equal to 0.005 percent; nb: 0.01-0.05%; ti: 0.010-0.030%; ni: 0.05-0.30%; cu: 0.20-0.50%; cr: 0.4-0.8%; n: less than or equal to 0.006 percent; ca: 0.0010-0.0030%; the balance of Fe and inevitable impurity elements. The weathering steel for the photovoltaic bracket has good weather resistance, reworkability, weldability and low-temperature toughness.
Description
Technical Field
The invention relates to the technical field of steel smelting, in particular to weather-resistant steel for a photovoltaic bracket and a production method thereof.
Background
Photovoltaic power generation is a green industry. The photovoltaic bracket is an important supporting and protecting structure of the photovoltaic power generation device. In order to prevent the photovoltaic bracket from being corroded, Q235 and Q355 steel plate coils or light-weight sections are mostly galvanized after being processed. But the hot galvanizing product causes pollution during production, and the treatment cost is greatly increased. In addition, most photovoltaic power generation devices are located in relatively open hillsides, sandy lands or pond zones, the area of a photovoltaic panel is large, reciprocating impact force transmitted to a support is large when the photovoltaic power generation devices are impacted by wind, sand, rain and snow, Q235 and Q355 belong to common low alloy materials, although the photovoltaic power generation devices have the characteristic of easiness in forming, the requirements for inclusion of sundries are not high, toughness and fatigue resistance are poor, brittle failure can occur in cold zones, and a complex application environment can easily cause damage to a zinc coating layer to cause early withdrawal of service. And the weathering steel for the photovoltaic bracket can completely avoid the problem. Because photovoltaic support processing style more requires full in-service life normal service simultaneously, therefore the weathering steel for photovoltaic support should possess following characteristic: the corrosion resistance index I is more than 6.0; the yield strength of the material is below 450MPa for easy reprocessing; the welding cold crack sensitivity coefficient is below 0.2; better low-temperature toughness; has certain fatigue resistance.
Chinese patent application No. 200910180491.1, which discloses "high strength low alloy hot rolled ferrite bainite weathering steel and method for producing the same", describes a weathering steel having low cost, high strength, low yield ratio, high weathering resistance, and good low temperature toughness and weldability. However, the weathering steel for the photovoltaic bracket needs more structural styles, so that the material has better processability and better fatigue resistance, the higher strength has the problem of high processing difficulty, many processing plants lack reprocessing capability due to too high strength, and in addition, a bainite structure with a higher proportion needs to be obtained in order to obtain high strength, the internal stress of the medium-temperature transformation structure is higher, and the toughness and the fatigue resistance are harmful.
The chinese patent document of patent application No. 200410061112.4 discloses "acicular structure high strength weathering steel and a production method thereof", which describes that an acicular structure high strength weathering steel is obtained by reducing the C content, controlling the relaxation for 20 to 100 seconds after rolling, and then controlling the cooling to 400 to 700 ℃. The method realizes high strength control and obtains better weather resistance through needle structure control, but the method disclosed by the literature needs relaxation after rolling control and is only suitable for medium plate rolling of a reversible mill set. And is not suitable for photovoltaic supports because the strength is too high.
Chinese patent application No. 200510045624.6 discloses "an economical weathering steel" produced by alloying Cu, Mn, Si, Al, etc. and simply adjusting a part of element content of a plain low carbon steel (Q235 steel) to have good atmospheric corrosion resistance and comprehensive mechanical properties. But the requirement of engineering on the corrosion resistance index is difficult to meet, and meanwhile, the low-temperature toughness is poor.
In the production of weathering resistant steel, more alloy elements such as Cu, Ni, Si, Cr and the like are required to be added for improving the corrosion resistance index, but the elements are all hardenability elements and are easy to improve the strength of the material, so that lower strength control is obtained under the condition of ensuring high corrosion resistance index, and the control can be realized only by a corresponding control process. In addition, charpy impact energy and drop hammer tests belong to the field of toughness test, and the low-temperature application safety of the material can be demonstrated by using the general weather-resistant steel as long as the weather-resistant steel has higher impact energy under the low-temperature condition. However, the Charpy impact energy is small because of the small impact sample, the crack lacks a large space, and the crack stopping capability of the material cannot be reflected. The photovoltaic support is frequently subjected to repeated impact of external force, so that the low-temperature Charpy impact work of the material is very important, the drop hammer test for showing the crack arrest capability is more important, and therefore the weather-resistant steel for the photovoltaic support and the production method thereof are designed, wherein the comprehensive performance of the weather-resistant steel is matched with the application requirement of the photovoltaic support.
Disclosure of Invention
The invention provides the weathering steel for the photovoltaic bracket and the production method thereof, which solve the problem that the combination property and the applicability of the weathering steel in the prior art are not easy to match when the weathering steel is applied to the photovoltaic bracket,
in order to achieve the purpose, the invention adopts the following technical scheme:
the weathering steel for the photovoltaic bracket comprises the following components in percentage by mass: c: 0.030-0.070%; si: 0.20-0.50%; mn: 0.3-1.20%; p: less than or equal to 0.020%; s: less than or equal to 0.005 percent; nb: 0.01-0.05%; ti: 0.010-0.030%; ni: 0.05-0.30%; cu: 0.20-0.50%; cr: 0.4-0.8%; n: less than or equal to 0.006 percent; ca: 0.0010-0.0030%; the balance of Fe and inevitable impurity elements.
Further, weld cold crack susceptibility: pcm is equal to or less than 0.18 of C + Si/30+ (Mn + Cu + Cr)/20+ Mo/15+ Ni/60+ V/10+ 5B;
further, corrosion resistance index: i ═ 26.01Cu +3.88Ni +1.2Cr +1.49Si +17.28P-7.92CuNi-9.1NiP-33.39Cu2≥6.0。
Further, its yield strength: 245-450 MPa; tensile strength: 420-600 MPa; elongation percentage: not less than 23 percent; the Charpy impact power is more than or equal to 120J at the temperature of minus 40 ℃; the drop hammer shear area at minus 20 ℃ is more than or equal to 85 percent; the grain size is more than or equal to grade 9; the level of the impurities is less than or equal to 1.5.
A production method of weathering steel for photovoltaic supports comprises the following steps:
firstly, smelting qualified molten steel by a molten iron pretreatment, a top and bottom combined blown converter, LF external refining and an RH vacuum degassing furnace, wherein the sulfur at the end point of the molten iron pretreatment is less than or equal to 20 ppm; the terminal oxygen of the top-bottom combined blown converter is less than or equal to 500 ppm; refining outside an LF furnace to produce white slag, wherein the white slag retention time is more than or equal to 15min, carrying out Ca treatment improvement and promoting floating of impurities, and carrying out soft stirring by adopting argon for more than or equal to 8 min; the vacuum degree of the RH vacuum degassing furnace is less than or equal to 100pa, and the holding time is more than or equal to 15 min;
step two, continuously casting molten steel into a 210mm plate blank;
step three, heating the steel billet to 1180-1250 ℃ for 120-180 min to ensure the sufficient solid solution of alloy elements;
rolling by adopting a TMCP (thermal mechanical control processing) process, wherein the rolling temperature of a recrystallization zone is 1050-1200 ℃, the total deformation rate is 70-80%, the starting temperature of an austenite non-recrystallization zone is 950-980 ℃, the total deformation amount is 70-85%, the control interval of a final rolling temperature is 880-920 ℃, and the precipitation of high-temperature pro-eutectoid ferrite is avoided;
step five, quickly feeding water after rolling is finished, and cooling to 570-650 ℃;
and step six, when the hot coil is at the temperature of more than 450 ℃, entering a slow cooling pit for slow cooling so as to fully release internal stress generated by rolling deformation and phase change, and taking out the hot coil after slow cooling for 48 hours and carrying out air cooling to room temperature.
Preferably, the sulfur at the end point of the molten iron pretreatment is less than or equal to 10 ppm;
preferably, the oxygen at the end point of the converter is controlled to be less than or equal to 400 ppm;
preferably, LF external refining is performed to produce white slag, the white slag retention time is more than or equal to 20min, Ca treatment improvement is performed to promote floating of inclusions, argon is used for soft stirring, and the soft stirring time is more than or equal to 10 min.
Preferably, the vacuum degree of the RH vacuum degassing furnace is less than or equal to 60pa, and the holding time is more than or equal to 15 min;
the inclusions, especially Al, which have a large influence on the fatigue resistance are minimized by the preferred measures described above2O3The impact of the inclusion on the fatigue resistance and simultaneously improve the low-temperature impact toughness and the weather resistance of the material.
The invention has the main characteristics that:
(1) by effectively combining the components and the process, the comprehensive performance of the steel meets the requirements of weather resistance, weldability and machinability required by the steel for the photovoltaic bracket. The crack arrest ability of the steel for the photovoltaic support is improved through the control of the drop hammer shearing area, and the toughness and the fatigue resistance of the steel for the photovoltaic support are improved.
(2) The quantity and the size of the inclusions are effectively reduced through the control of nitrogen, oxygen and sulfur, and the weather resistance, the weldability, the low-temperature toughness and the fatigue resistance of the steel are improved.
(3) Fully elongating austenite grains by controlling rolling, rapidly cooling after finishing rolling in an austenite region to obtain supercooled austenite with larger supercooling degree, shortening the diffusion stroke of carbon, improving the phase change nucleation point, and obtaining uniform ferrite and a small amount of pearlite or bainite tissue with finer dispersion distribution in the subsequent phase change process. Thereby obtaining good low-temperature toughness.
(4) As the final rolling temperature is reduced in the austenite region, more dislocations are formed in the rolling process, the yield strength and the tensile strength can be greatly improved by dislocation strengthening, but the reworkability of the material is reduced, and the dislocation strengthening effect can be effectively reduced by taking measures of increasing the final rolling temperature. And further the strength performance of the steel can meet the requirements of the steel for the photovoltaic bracket.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.
Example 1
The weathering steel for the photovoltaic bracket and the production method thereof provided by the embodiment specifically comprise the following steps:
the smelting components in percentage by mass are as follows: c: 0.061%; si: 0.36 percent; mn: 0.55 percent; p: 0.011 percent; s: less than or equal to 0.002 percent; nb: 0.015 percent; ti: 0.013%; ni: 0.15 percent; cu: 0.30 percent; cr: 0.50 percent; n: 0.0049%; ca: 0.0015 percent; the balance of Fe and inevitable impurity elements;
the corrosion resistance index calculation mode is as follows: i ═ 26.01Cu +3.88Ni +1.2Cr +1.49Si +17.28P-7.92CuNi-9.1NiP-33.39Cu2 ═ 6.37;
the welding cold crack sensitivity coefficient calculation mode is as follows: Pcm-C + Si/30+ (Mn + Cu + Cr)/20+ Mo/15+ Ni/60+ V/10+ 5B-0.15;
a production method of weathering steel for photovoltaic supports comprises the following steps:
firstly, smelting qualified molten steel by a molten iron pretreatment, a top and bottom combined blown converter, LF external refining and an RH vacuum degassing furnace, wherein the final sulfur content of the molten iron pretreatment is 9 ppm; the terminal oxygen of the top-bottom combined blown converter is 310 ppm; refining outside an LF furnace to produce white slag, keeping the white slag for 20min, performing Ca treatment improvement and promoting impurities to float, and performing soft stirring by adopting argon for 11 min; the vacuum degree of the RH vacuum degassing furnace is 60pa, and the holding time is 18 min;
step two, continuously casting molten steel into a 210mm plate blank;
step three, heating the steel billet to 1210 ℃ for 155min to ensure the full solid solution of the alloy elements;
step four, rolling by adopting a TMCP process, wherein the rolling temperature of a recrystallization zone is 1085 ℃, the total deformation rate is 74%, the starting temperature of an austenite non-recrystallization zone is 970 ℃, the total deformation amount is 79.3%, the control interval of the finish rolling temperature is 910 ℃, and the precipitation of high-temperature pro-eutectoid ferrite is avoided;
step five, rapidly introducing water after rolling, wherein the cooling rate is 25 ℃/s, and cooling to 640 ℃;
and step six, the hot coil enters a slow cooling pit at 590 ℃ for slow cooling so as to fully release internal stress generated by rolling deformation and phase change, and the hot coil is taken out of the slow cooling pit after 48 hours and cooled to room temperature in an air cooling mode.
Sampling and inspecting: the structure is uniform ferrite and a small amount of dispersed pearlite structure; yield strength: 300MPa, tensile strength: 451MPa, elongation: 28.5 percent; -impact work at 40 ℃ of 268J, -drop shear area at 20 ℃: 98 percent; grain size: 10.5 grade, and the inclusions are all below grade 1.
Example 2
The weathering steel for the photovoltaic bracket and the production method of the weathering steel comprise the following concrete implementation steps:
c: 0.043 percent; si: 0.35 percent; mn: 0.86 percent; p; 0.014%; s: less than or equal to 0.001 percent; nb: 0.028%; ti: 0.012%; ni: 0.15 percent; cu: 0.37 percent; cr: 0.52 percent; n: 0.0051%; ca: 0.0017%; the balance of Fe and inevitable impurity elements;
calculating the corrosion resistance index: i ═ 26.01Cu +3.88Ni +1.2Cr +1.49Si +17.28P-7.92CuNi-9.1NiP-33.39Cu2 ═ 6.6;
calculating the welding cold crack sensitivity coefficient: Pcm-C + Si/30+ (Mn + Cu + Cr)/20+ Mo/15+ Ni/60+ V/10+ 5B-0.15;
a production method of weathering steel for photovoltaic supports comprises the following steps:
step one, smelting qualified molten steel through a molten iron pretreatment, a top-bottom combined blown converter, LF external refining and an RH vacuum degassing furnace. Wherein the sulfur content at the end point of the molten iron pretreatment is 8 ppm; the terminal oxygen of the top-bottom combined blown converter is 380 ppm; refining outside an LF furnace to produce white slag, keeping the white slag for 21min, performing Ca treatment improvement and promoting impurities to float, and performing soft stirring by adopting argon for 12 min; the vacuum degree of the RH vacuum degassing furnace is 56pa, and the holding time is 18 min;
step two, continuously casting molten steel into a 210mm plate blank;
step three, heating the steel billet to 1220 ℃, wherein the heating time is 160min, and ensuring the full solid solution of the alloy elements;
step four, rolling by adopting a TMCP process, wherein the rolling temperature of a recrystallization zone is 1090 ℃, the total deformation rate is 74.7%, the starting temperature of an austenite non-recrystallization zone is 965 ℃, the total deformation amount is 79.3%, and the control interval of the finish rolling temperature is 895 ℃, so that the precipitation of high-temperature proeutectoid ferrite is avoided;
step five, rapidly introducing water after rolling is finished, wherein the cooling rate is 26 ℃/s, and cooling to 620 ℃;
and step six, the hot coil enters a slow cooling pit at 550 ℃ for slow cooling so as to fully release internal stress generated by rolling deformation and phase change, and the hot coil is taken out of the slow cooling pit after 48 hours and cooled to room temperature in an air cooling mode.
Sampling and inspecting: the structure is uniform ferrite and a small amount of dispersed pearlite structure; yield strength: 406MPa, tensile strength: 539MPa, elongation: 26 percent; -impact work at 40 ℃ of 273J, -drop shear area at 20 ℃: 98.5 percent; grain size: grade 11.5, and all inclusions are below grade 1.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered as the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.
Claims (3)
1. The weathering steel for the photovoltaic bracket is characterized by comprising the following components in percentage by mass: c: 0.030-0.070%; si: : 0.20-0.50%; mn: 0.3-1.20%; p: less than or equal to 0.020%; s: less than or equal to 0.005 percent; nb: 0.01-0.05%; ti: 0.010-0.030%; ni: 0.05-0.30%; cu: 0.20-0.50%; cr: 0.4-0.8%; n: less than or equal to 0.006 percent; ca: 0.0010-0.0030%; the balance of Fe and inevitable impurity elements.
2. The weathering steel for photovoltaic support according to claim 1, characterized by the following yield strength: 245-450 MPa; tensile strength: 420-600 MPa; elongation percentage: not less than 23 percent; the Charpy impact power is more than or equal to 120J at the temperature of minus 40 ℃; the drop hammer shear area at the temperature of minus 20 ℃ is more than or equal to 85 percent; the grain size is more than or equal to grade 9; the grade of each inclusion is less than or equal to 1.5. The welding cold crack sensitivity coefficient Pcm is less than or equal to 0.18; the corrosion resistance index I is more than or equal to 6.0.
3. The production method of the weathering steel for photovoltaic support according to claim 2, characterized by comprising the following steps:
(1) smelting qualified molten steel by a molten iron pretreatment, a top and bottom combined blown converter, LF external refining and an RH vacuum degassing furnace; wherein the sulfur at the end point of the molten iron pretreatment is less than or equal to 20 ppm; the terminal oxygen of the top-bottom combined blown converter is less than or equal to 500ppm, the LF is refined outside the furnace to produce white slag, the white slag retention time is more than or equal to 15min, Ca treatment improvement is carried out, floating of inclusions is promoted, argon is adopted for soft stirring, the soft stirring time is more than or equal to 8min, the vacuum degree of the RH vacuum degassing furnace is less than or equal to 100pa, and the retention time is more than or equal to 15 min;
(1) continuously casting the molten steel into a 210mm plate blank;
(2) after the slab is cooled in a heaped mode for 48 hours, heating the steel billet to 1180-1250 ℃ for 120-180 min to ensure that alloy elements are fully dissolved in solid solution;
(3) rolling by adopting a TMCP (thermal mechanical control processing) process, wherein the rolling temperature of a recrystallization zone is 1050-1200 ℃, the total deformation rate is 70-80%, the starting temperature of an austenite non-recrystallization zone is 950-980 ℃, the total deformation amount is 70-85%, and the control interval of the finish rolling temperature is 880-920 ℃;
(4) quickly introducing water after rolling, and cooling to 570-650 ℃;
(5) and (4) slowly cooling the hot coil in a slow cooling pit when the temperature of the hot coil is more than 450 ℃, taking out the hot coil after slowly cooling for 48 hours, and air-cooling to room temperature.
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| JPH0525584A (en) * | 1991-07-23 | 1993-02-02 | Sumitomo Metal Ind Ltd | High weather resistant steel plate excellent in weldability and its production |
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| CN108239722A (en) * | 2018-03-02 | 2018-07-03 | 山东钢铁股份有限公司 | The Weather-resistance bridge steel plate and its production method of a kind of yield strength >=420MPa |
| CN113201687A (en) * | 2021-03-30 | 2021-08-03 | 唐山钢铁集团有限责任公司 | 420 MPa-grade weather-proof bridge steel and production method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0525584A (en) * | 1991-07-23 | 1993-02-02 | Sumitomo Metal Ind Ltd | High weather resistant steel plate excellent in weldability and its production |
| CN105331880A (en) * | 2015-11-12 | 2016-02-17 | 江阴兴澄特种钢铁有限公司 | High-strength weather-proof bridge steel and preparation method thereof |
| CN108239722A (en) * | 2018-03-02 | 2018-07-03 | 山东钢铁股份有限公司 | The Weather-resistance bridge steel plate and its production method of a kind of yield strength >=420MPa |
| CN113201687A (en) * | 2021-03-30 | 2021-08-03 | 唐山钢铁集团有限责任公司 | 420 MPa-grade weather-proof bridge steel and production method thereof |
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