CN115386801A - 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate and production method thereof - Google Patents
400 MPa-grade Ni-free hot-rolled weather-resistant steel plate and production method thereof Download PDFInfo
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- 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
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- 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
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- 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
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- 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
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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Abstract
The invention discloses a 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate and a production method thereof, wherein the weather-resistant steel plate comprises the following chemical components in percentage by weight: c:0.07 to 0.11%, si: 0.30-0.55%, mn:0.30 to 0.50%, P:0.020 to 0.150%, S: less than or equal to 0.005 percent, cr:0.30% -0.80%, cu:0.25% -0.40%, als:0.015% -0.040%, ti:0.015% -0.040%, N: the invention solves the control problems of continuous casting bleed-out of 400MPa grade Ni-free weathering steel and surface crack defects of hot rolled coils by the cooperative design of alloy components, smelting, continuous casting and hot rolling, and realizes the batch stable production of 400MPa grade Ni-free hot rolled weathering steel plates under the conventional process.
Description
Technical Field
The invention belongs to the field of steel materials, and particularly relates to a 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate and a production method thereof.
Background
The weathering steel is atmospheric corrosion resistant steel, which is a kind of low alloy steel added with a small amount of alloy elements such as Cu, P, cr, ni and the like on the basis of common carbon steel. When the weathering steel is used in atmospheric environment, a compact and firmly adhered amorphous protective rust layer is formed on the surface of a steel matrix, so that corrosive media such as oxygen, water and the like in the air are prevented from diffusing to the matrix, and the atmospheric corrosion resistance is improved. The weathering steel has good atmospheric corrosion resistance, obdurability and welding performance, prolongs the service life, and is widely applied to the manufacture of steel structures of railway vehicles, containers, buildings, bridges, towers and the like.
Cu is one of the most main alloy elements in the weathering steel, and can obviously improve the atmospheric corrosion resistance of steel. However, cu is an alloy element with a low melting point, the melting point is only 1083 ℃, bleed-out is easily generated in the continuous casting process of the weathering resistant steel due to the existence of Cu, and surface quality defects such as edge cracks, surface warping and the like are generated in the heating and hot rolling processes of a hot rolled coil. In the prior weathering resistant steel, cu and Ni are added in a compounding way, ni/Cu is controlled to be more than or equal to 0.5, a Cu-Ni binary alloy phase with a high melting point is formed, liquid phase copper enrichment is inhibited, and the problem existing in the manufacturing process is solved. Ni can promote the forward shift of the self-corrosion potential of the steel, reduce the corrosion tendency, enrich in a rust layer, promote the formation of a compact inner rust layer and improve the atmospheric corrosion resistance of the material. However, ni is a precious alloy element, and the addition of Ni not only obviously improves the manufacturing cost of the weathering steel, but also accelerates the consumption of Ni resources in China.
Disclosure of Invention
In order to solve the technical problems, the invention provides a 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate and a production method thereof, the production cost of the weather-resistant steel plate is greatly reduced, the weather-resistant steel plate has good atmospheric corrosion resistance and comprehensive mechanical properties, and the thickness of the plate is more than or equal to 3.0mm.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a400 MPa-grade Ni-free hot-rolled weather-resistant steel plate comprises the following chemical components in percentage by weight: c:0.07 to 0.11%, si: 0.30-0.55%, mn:0.30 to 0.50%, P:0.020 to 0.150%, S: less than or equal to 0.005%, cr:0.30% -0.80%, cu:0.25% -0.40%, als:0.015% -0.040%, ti:0.015% -0.040%, N: less than or equal to 0.0050 percent, and the balance of Fe and inevitable impurity elements, and the weather resistance index I of the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate is more than or equal to 7.0.
The metallographic structure of the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate is polygonal ferrite and pearlite.
Yield strength R of 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate eL Not less than 400MPa, tensile strength Rm not less than 500MPa, elongation A not less than 25%, and-20 deg.C KV 2 ≥100J。
The production method of the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate comprises the following steps: molten iron pretreatment deep desulfurization → converter top and bottom combined blowing → LF refining → continuous casting → heating → hot continuous rolling → laminar cooling → coiling.
In the continuous casting step, casting with low superheat degree and special Ni-free weather-resistant steel covering slag are adopted for casting protection to avoid steel leakage. The superheat degree of the molten steel of the tundish is controlled at 10-25 ℃; the main physical and chemical performance indexes of the covering slag are as follows: alkalinity is 0.90-1.40, viscosity at 1300 ℃ is 0.030-0.150 Pa.s, melting point is 1030-1150 ℃.
In the continuous casting step, the thickness of the continuous casting slab is 230mm or 250mm, and the drawing speed of the continuous casting slab is controlled to be less than or equal to 1.5m/min. After the casting blank is cut, direct charging or hot charging rolling is adopted, the charging temperature of the plate blank is more than or equal to 600 ℃, and the time of the plate blank in a heating furnace is shortened.
In the heating step, the plate blank enters a walking beam type heating furnace for heating, in order to avoid the surface defect of copper brittleness caused by a low-melting point alloy element Cu, the outlet temperature of a first heating section of the heating furnace is controlled to be less than 1070 ℃, the temperature of a second heating section is rapidly increased to 1150-1200 ℃ at the temperature increasing rate of more than or equal to 150 ℃/h, the tapping temperature of the plate blank is less than or equal to 1200 ℃, and the furnace time is 120-180 min; the low-temperature rapid heating is adopted, the furnace time is shortened, and the enrichment of liquid phase Cu in the austenite grain boundary is reduced.
In the heating step, the heating furnace adopts a reducing atmosphere, the air excess coefficient is less than 1.0, the oxidation burning loss of Fe on the surface of the plate blank in the heating process is reduced, and the Cu enrichment is inhibited.
And (3) after the plate blank is taken out of the heating furnace, carrying out high-pressure water descaling to remove primary iron scale on the surface of the plate blank, and then carrying out hot continuous rolling.
In the hot continuous rolling step, the rolling temperature in the rough rolling stage is controlled to be over 1050 ℃, the accumulated reduction rate is more than or equal to 80%, and multi-pass large deformation is carried out at high temperature, so that the recovery and recrystallization of deformed austenite grains are promoted, and the grain size of austenite refined grains is refined. And a heat preservation cover is adopted between the rough rolling unit and the finishing rolling unit to preserve heat of the intermediate billet, so that the head and tail temperature uniformity of the intermediate billet is improved. And in the finish rolling stage, 7 four-high rolling mills are adopted for continuous rolling, the finish rolling initial rolling temperature is less than or equal to 1030 ℃, the accumulated deformation is more than or equal to 80%, the deformation zone and the dislocation density in the deformed austenite are increased through accumulated large deformation, the ferrite phase transformation nucleation point is increased, and ferrite grains after phase transformation are refined. In order to ensure the grain refining effect, the finish rolling temperature is controlled to be 830-890 ℃.
In the laminar cooling step, the front-section dense laminar cooling is adopted to promote the rapid cooling of the strip steel after the finish rolling, and the cooling speed is more than or equal to 30 ℃/s.
In the coiling step, the coiling temperature is controlled to be 570-640 ℃; the coiling temperature is too high, ferrite grains and second phase precipitated particles are coarsened, and the strength is insufficient; the bainite structure is generated at the low coiling temperature, the plasticity of the material is reduced, and the forming performance is influenced. And naturally cooling to room temperature after coiling.
The design principles of alloy elements and mass percent thereof in the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate are as follows:
c (carbon): c is the most economical element for improving the strength of the steel, but the welding performance of the steel is deteriorated and the ductility and toughness are reduced due to the over-high content of C; but also aggravate electrochemical corrosion between different phases and deteriorate atmospheric corrosion resistance. In order to improve the strength of the weathering steel, the content of C is designed to be 0.07-0.11%.
Si (silicon): si is beneficial to refining corrosion products, promotes the formation of a compact protective rust layer on the surface of steel so as to improve the atmospheric corrosion resistance, and can also inhibit the oxidation burning loss of Fe in the heating process so as to inhibit the copper enrichment. However, too high Si content may deteriorate the weldability of the steel. Therefore, the Si content is designed to be 0.30-0.55%.
Mn (manganese): mn is one of important solid solution strengthening elements in steel, and improves the strength and toughness of the steel. However, too high Mn content increases the production cost of the weathering steel and deteriorates the weldability of the steel. Therefore, the content is designed to be 0.30 to 0.50%.
P (phosphorus): p is the most economical element for improving the atmospheric corrosion resistance of the steel and can also play a role in solid solution strengthening, but the P content is too high, so that the low-temperature toughness of the steel is easily reduced by segregation at grain boundaries, and the welding crack sensitivity is increased. Therefore, the content of P is designed to be 0.020-0.150%;
s (sulfur): s is a harmful residual element in steel, deteriorates the atmospheric corrosion resistance and ductility and toughness of steel, and is easily combined with Ti and C to form Ti 4 C 2 S 2 And the content of effective Ti in the steel is reduced, so that the strengthening effect of the microalloy element Ti is influenced. Therefore, the S content is designed to be less than or equal to 0.005 percent.
Als (aluminum): al is the main deoxidizing element added into steel, the bonding force with oxygen is greater than that of Ti, and the yield of Ti is improved. However, the high Al content causes the increase of Al oxide inclusions in steel, reduces the atmospheric corrosion resistance of steel, and easily blocks a water gap in continuous casting. Therefore, the content is designed to be 0.015 to 0.040%.
Cr (chromium): cr is an important alloy element for improving the atmospheric corrosion resistance of steel, and particularly can enrich and promote the generation of a compact protective rust layer on the surface of the steel when being added with Cu in a compounding way, so that the atmospheric corrosion resistance of the steel is obviously improved. However, too high Cr content deteriorates the weldability of the steel. Therefore, the Cr content is designed to be 0.30 to 0.80%.
Cu is a main atmospheric corrosion resistant element, and can also precipitate fine second phase particles in the cooling process to improve the strength; however, the melting point of Cu is low, and the Cu content is designed to be 0.25 to 0.40% because continuous casting breakout is easily caused by an excessively high content and surface cracks are generated during hot rolling.
Ti (titanium): ti is the most economical microalloy element for improving the strength of steel, is a strong nitride forming element, has higher TiN solid solution temperature, can inhibit the growth of austenite grains in the heating process, refine the grain size and improve the strength, can also increase the austenite grain interfacial area and reduce the enrichment degree of liquid phase copper in the austenite grain boundary. Fine TiC two-phase particles are precipitated in the coiling process, the strength is improved through precipitation strengthening, and the content of the TiC two-phase particles is controlled to be 0.015-0.040%.
N (nitrogen): n is a residual element in molten steel, and can be combined with Ti to form TiN so as to inhibit austenite grains from growing. However, the effective Ti content in the steel can be reduced and the fine grain strengthening and precipitation strengthening effects of Ti can be reduced due to the over-high N content, so that the N content is controlled to be less than or equal to 0.0050 percent.
The chemical composition design of the invention also needs to meet the following requirementsConditions are as follows: the weathering index I of this steel grade was calculated with reference to the formula Legault-Leckie modified in the American society for testing and materials Standard ASTM G101-01, I =26.01 (% Cu) +3.88 (% Ni) +1.20 (% Cr) +1.49 (% Si) +17.28 (% P) -7.29 (% Cu) × (% Ni) -9.10 (% Ni) × (% P) -33.39 (% Cu) 2 . The atmospheric corrosion resistance of the material is increased along with the increase of the I value, and the material has good atmospheric corrosion resistance when the I value is more than or equal to 6.0. The chemical composition design of the invention also needs to satisfy the condition that I is more than or equal to 7.0.
The invention solves the difficult problem of controlling the surface crack defects of continuous casting breakout and hot rolled coils of Ni-free Cu-containing weathering steel by the collaborative design of alloy components, smelting, continuous casting and hot rolling in the whole process, realizes the batch stable production of 400 MPa-level Ni-free Cu-containing hot rolled weathering steel plates under the conventional process, and the produced 400 MPa-level Ni-free weathering steel plates have the thickness of more than or equal to 3.0mm and the yield strength R of more than or equal to 3.0mm eL Not less than 400MPa, tensile strength Rm not less than 500MPa, elongation A not less than 25%, and-20 deg.C KV 2 The J is more than or equal to 100J. No crack appears on the outer side surface of the sample after double cold bending, and the cold bending forming performance is good.
According to the production method of the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate, steel leakage does not occur in the continuous casting process, the surface of a hot-rolled coil of the product is free from warping, the edge part of the hot-rolled coil is free from crack defects, the manufacturing cost is obviously reduced, and the precious metal Ni resource is saved.
According to the invention, a proper amount of P and Si are added into the components of the 400 MPa-level Ni-free hot-rolled weather-resistant steel plate, and the corrosion resistance is improved by 1 time relative to Q345B through the matching design and interaction of Si-P-Cu-Cr elements, so that the steel plate has good atmospheric corrosion resistance. The scheme can be used for manufacturing weathering resistant steel such as containers, cable bridges, photovoltaic supports, chimneys, heat exchangers and the like.
Drawings
FIG. 1 is a metallographic structure diagram of a weathering steel sheet in example 3;
FIG. 2 is a graph of the edge macrostructures of a hot-rolled coil of the weathering steel sheet in example 3;
FIG. 3 is a surface macro topography of the weathering steel plate of example 3.
Detailed Description
The invention provides a 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate which comprises the following chemical components in percentage by mass: c:0.07 to 0.11%, si: 0.30-0.55%, mn:0.30 to 0.50%, P:0.020 to 0.150%, S: less than or equal to 0.005%, cr:0.30% -0.80%, cu: 0.25-0.40%, als:0.015% -0.040%, ti:0.015% -0.040%, N: less than or equal to 0.0050 percent, and the balance of Fe and inevitable impurity elements, and the Ni-free 400 MPa-grade hot-rolled weather-resistant steel plate has a weather resistance index I of more than or equal to 7.0.
The production method of the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate comprises the following steps: molten iron pretreatment deep desulfurization → converter top and bottom combined blowing → LF refining → continuous casting → heating → hot continuous rolling → laminar cooling → coiling.
In the continuous casting step, the superheat degree of the molten steel of the tundish is controlled at 10-25 ℃; casting the protecting slag with alkalinity of 0.90-1.40, viscosity of 0.030-0.150 Pa.s at 1300 ℃ and melting point of 1030-1150 ℃;
in the continuous casting step, the drawing speed of the continuous casting billet is controlled to be less than or equal to 1.5m/min, and the thickness of the continuous casting slab is 230mm or 250mm;
in the heating step, a casting blank obtained by continuous casting is directly hot-charged and rolled after being cut, the feeding temperature of the plate blank is more than or equal to 600 ℃, the outlet temperature of the first feeding section of the heating furnace is controlled to be less than 1070 ℃, the temperature of the second feeding section is quickly raised to 1150-1200 ℃ at the temperature raising rate of more than or equal to 150 ℃/h, the discharging temperature of the plate blank is less than or equal to 1200 ℃, and the furnace time is 120-180 min.
In the heating step, the heating furnace adopts reducing atmosphere, and the air excess coefficient is less than 1.0;
and (3) after the plate blank is taken out of the heating furnace, carrying out high-pressure water descaling to remove primary iron scale on the surface of the plate blank, and then carrying out hot continuous rolling.
In the hot continuous rolling step, the rolling temperature in the rough rolling stage is controlled to be more than 1050 ℃, the accumulated reduction rate is more than or equal to 80%, a heat preservation cover is adopted between a rough rolling unit and a finishing rolling unit to preserve the heat of the intermediate billet, a 7-frame four-roller rolling machine is adopted in the finish rolling stage to carry out continuous rolling, the finish rolling initial temperature is less than or equal to 1030 ℃, the accumulated deformation is more than or equal to 80%, and the finish rolling temperature is controlled to be 830-890 ℃.
In the laminar cooling step, the front-section dense laminar cooling is adopted to promote the rapid cooling of the strip steel after the finish rolling, and the cooling speed is more than or equal to 30 ℃/s.
In the coiling step, the coiling temperature is controlled to be 570-640 ℃.
The technical solution of the present invention is further illustrated by the following specific examples.
The chemical components of the weathering steel in each example and each comparative example are shown in Table 1, the weathering index I of each example is more than 7.0, and the weathering steel has excellent atmospheric corrosion resistance.
TABLE 1 chemical composition of examples of the invention and comparative examples
The main process parameters and mechanical properties of the rolling process of the weathering steel in the examples and comparative examples are shown in tables 2 and 3, respectively. Tensile properties test according to GB/T228.1-2010 "metallic materials tensile test part 1: the test method for the room temperature is carried out, and the cold bending performance test is carried out according to GB/T232-2010 metal material bending test method.
TABLE 2 Main technological parameters of rolling procedures of inventive examples and comparative examples
TABLE 3 mechanical Properties and surface qualities of inventive and comparative examples
Wherein the metallographic structure and the macroscopic topography of the surface and the edge of the hot-rolled coil of the weathering steel plate in the embodiment 3 are respectively shown in fig. 1, 2 and 3, and fig. 1 shows that the typical microstructure of the weathering steel plate is polygonal ferrite + pearlite, wherein the average grain size of the ferrite is 13 μm, and the volume fraction is 93.4 percent, thus the invention can control the microstructure of the steel plate to be mainly polygonal ferrite with better ductility and toughness and improve the plasticity and low-temperature toughness of the material through the synergistic design of alloy components and controlled rolling and controlled cooling processes; FIG. 2 shows a weatherable steel hot rolled coil without edge crack defects; FIG. 3 shows that the surface of the weathering steel plate has no warping defect.
A72 h periodic immersion corrosion test was performed according to TB/T2375, with the pattern dimensions: the test results are shown in Table 4, with a comparison sample of 40mm 60mm 2mm and Q345B low alloy steel. The atmospheric corrosion resistance of each embodiment is improved by 1 time compared with Q345B low alloy steel, and the alloy steel has good atmospheric corrosion resistance.
TABLE 4 atmospheric corrosion resistance of the examples and comparative samples
| Average corrosion weight loss rate, (g/(m) 2 ·h)) | Relative corrosion rate% | |
| Example 1 | 2.20 | 48 |
| Example 2 | 2.23 | 49 |
| Example 3 | 2.18 | 48 |
| Example 4 | 2.24 | 49 |
| Example 5 | 2.28 | 50 |
| Q345B | 4.54 | 100 |
In conclusion, the Ni-free weather-resistant steel plate produced by the technology has the yield strength of more than or equal to 400MP, the tensile strength of more than or equal to 500MPa, the elongation of more than or equal to 27 percent and KV at the temperature of-20 DEG C 2 The J is more than or equal to 100J. The production cost is greatly reduced, and the product has good atmospheric corrosion resistance and cold-bending forming performance, and can be applied to manufacturing containers, railway vehicles, photovoltaic brackets, cable bridges, chimneys and the like.
The above detailed description of a Ni-free 400MPa grade hot rolled weathering steel sheet and the method of manufacturing the same with reference to the examples is illustrative and not restrictive, and several examples are listed within the limits, so that variations and modifications without departing from the general concept of the present invention shall fall within the protection scope of the present invention.
Claims (10)
1. A400 MPa-grade Ni-free hot-rolled weather-resistant steel plate is characterized by comprising the following chemical components in percentage by weight: c:0.07 to 0.11%, si: 0.30-0.55%, mn:0.30 to 0.50%, P:0.020 to 0.150%, S: less than or equal to 0.005 percent, cr: 0.30-0.80%, cu:0.25% -0.40%, als:0.015% -0.040%, ti:0.015% -0.040%, N: less than or equal to 0.0050 percent, and the balance of Fe and inevitable impurity elements, and the weather resistance index I of the 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate is more than or equal to 7.0.
2. The 400MPa grade Ni-free hot-rolled weathering steel plate of claim 1, wherein the metallographic structure of the 400MPa grade Ni-free hot-rolled weathering steel plate is polygonal ferrite + pearlite.
3. The 400MPa grade Ni-free hot rolled weathering steel plate of claim 1, wherein the 400MPa grade Ni-free hot rolled weathering steel plate has a yield strength R eL Not less than 400MPa, tensile strength Rm not less than 500MPa, elongation A not less than 25%, and-20 deg.C KV 2 ≥100J。
4. The method for producing the 400MPa grade Ni-free hot rolled weathering steel plate of any of claims 1 to 3, characterized in that it comprises the following steps: molten iron pretreatment deep desulfurization → converter top and bottom combined blowing → LF refining → continuous casting → heating → hot continuous rolling → laminar cooling → coiling.
5. The production method according to claim 4, wherein in the continuous casting step, the superheat degree of the molten steel in the tundish is controlled to be 10-25 ℃; the casting powder with alkalinity of 0.90-1.40, viscosity of 0.030-0.150 Pa.s at 1300 ℃ and melting point of 1030-1150 ℃ is used for casting.
6. The production method according to claim 4, wherein in the heating step, the cast blank obtained by continuous casting is directly hot-charged and rolled after being cut, and the charging temperature of the slab is more than or equal to 600 ℃; the outlet temperature of the first feeding section of the heating furnace is controlled to be less than 1070 ℃, the temperature of the second feeding section is rapidly increased to 1150-1200 ℃ at the temperature increasing rate of more than or equal to 150 ℃/h, the tapping temperature of the plate blank is less than or equal to 1200 ℃, and the furnace time is 120-180 min.
7. The production method according to claim 4, wherein in the heating step, the heating furnace uses a reducing atmosphere, and the air excess coefficient is less than 1.0.
8. The production method according to claim 4, wherein in the hot continuous rolling step, the rolling temperature in the rough rolling stage is controlled to be 1050 ℃ or higher; and in the finish rolling stage, 7 four-roller rolling mills are adopted for continuous rolling, the finish rolling initial temperature is less than or equal to 1030 ℃, the accumulated deformation is more than or equal to 80%, and the finish rolling temperature is controlled to be 830-890 ℃.
9. The production method according to claim 4, wherein in the laminar cooling step, the front-stage intensive laminar cooling is adopted after the finish rolling, and the cooling speed is not less than 30 ℃/s.
10. The production method according to claim 4, wherein in the winding step, the winding temperature is controlled to 570 to 640 ℃.
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| CN202211055017.8A Pending CN115386801A (en) | 2022-08-30 | 2022-08-30 | 400 MPa-grade Ni-free hot-rolled weather-resistant steel plate and production method thereof |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH032321A (en) * | 1989-05-30 | 1991-01-08 | Nippon Steel Corp | Manufacture of high strength weather-resisting hot rolled steel sheet |
| US20140366602A1 (en) * | 2012-03-14 | 2014-12-18 | Baoshan Iron & Steel Co., Ltd. | Method for Manufaturing Thin Strip Continuously Cast 700MPa-Grade High Strength Weather-Resistant Steel |
| CN106282831A (en) * | 2015-05-25 | 2017-01-04 | 宝山钢铁股份有限公司 | A kind of high-strength container weather resisting steel and manufacture method thereof |
| CN108994268A (en) * | 2018-09-03 | 2018-12-14 | 本钢板材股份有限公司 | A kind of 550MPa grades of hot rolling container weathering steel and its manufacturing method |
| CN111534746A (en) * | 2020-04-30 | 2020-08-14 | 鞍钢股份有限公司 | Weather-resistant steel for wide 450 MPa-grade hot-rolled container and manufacturing method thereof |
| CN113020257A (en) * | 2019-12-09 | 2021-06-25 | 上海梅山钢铁股份有限公司 | Method for eliminating surface warping defect of weather-resistant steel plate blank in hot rolling process |
| CN113234994A (en) * | 2021-04-14 | 2021-08-10 | 马鞍山钢铁股份有限公司 | Hot-rolled high-strength weather-resistant steel plate with yield strength of 600MPa and production method thereof |
| CN114480972A (en) * | 2022-01-27 | 2022-05-13 | 马鞍山钢铁股份有限公司 | Thin-specification Ni-free weathering steel produced based on CSP process and production method thereof |
-
2022
- 2022-08-30 CN CN202211055017.8A patent/CN115386801A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH032321A (en) * | 1989-05-30 | 1991-01-08 | Nippon Steel Corp | Manufacture of high strength weather-resisting hot rolled steel sheet |
| US20140366602A1 (en) * | 2012-03-14 | 2014-12-18 | Baoshan Iron & Steel Co., Ltd. | Method for Manufaturing Thin Strip Continuously Cast 700MPa-Grade High Strength Weather-Resistant Steel |
| CN106282831A (en) * | 2015-05-25 | 2017-01-04 | 宝山钢铁股份有限公司 | A kind of high-strength container weather resisting steel and manufacture method thereof |
| CN108994268A (en) * | 2018-09-03 | 2018-12-14 | 本钢板材股份有限公司 | A kind of 550MPa grades of hot rolling container weathering steel and its manufacturing method |
| CN113020257A (en) * | 2019-12-09 | 2021-06-25 | 上海梅山钢铁股份有限公司 | Method for eliminating surface warping defect of weather-resistant steel plate blank in hot rolling process |
| CN111534746A (en) * | 2020-04-30 | 2020-08-14 | 鞍钢股份有限公司 | Weather-resistant steel for wide 450 MPa-grade hot-rolled container and manufacturing method thereof |
| CN113234994A (en) * | 2021-04-14 | 2021-08-10 | 马鞍山钢铁股份有限公司 | Hot-rolled high-strength weather-resistant steel plate with yield strength of 600MPa and production method thereof |
| CN114480972A (en) * | 2022-01-27 | 2022-05-13 | 马鞍山钢铁股份有限公司 | Thin-specification Ni-free weathering steel produced based on CSP process and production method thereof |
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