CN109234633B - Rare earth treated high-strength steel plate with low preheating temperature of 690MPa level and preparation method thereof - Google Patents
Rare earth treated high-strength steel plate with low preheating temperature of 690MPa level and preparation method thereof Download PDFInfo
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Abstract
The invention provides a rare earth treated high-strength steel plate with a low preheating temperature of 690MPa grade and a preparation method thereof, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.09-0.15%, Si: 0.30-0.45%, Mn: 1.58-1.75%, P is less than or equal to 0.02%, S is less than or equal to 0.010%, Nb: 0.04-0.08%, V: 0.05-0.08%, Ti: 0.010-0.020%, Cr: 0.20-0.40%, La is less than or equal to 0.030%, Alt: 0.020-0.050%, N is less than or equal to 0.005%, and O is less than or equal to 0.004%. The 690 MPa-grade high-strength steel plate obtained by the invention is added with rare earth but not added with Ni and Mo, has low preheating temperature, reduces the cost, improves the comprehensive mechanical property by rare earth treatment, prolongs the service life and has good economic benefit.
Description
Technical Field
The invention belongs to the technical field of metallurgical materials, particularly relates to the field of steel for high-strength engineering machinery, and particularly relates to rare earth treated 690 MPa-grade high-strength steel with low preheating temperature and a preparation method thereof.
Background
With the development of engineering machinery towards equipment upsizing, light weight, heavy load and the like, the high-strength steel shows a wide prospect of new materials in the application of downstream deep processing industrial chains, the use amount of the high-strength steel plate shows a trend of increasing continuously, and the strength grade and the like are also improved quickly. In engineering machinery products, the welded structural part accounts for about 50-70% of the weight of the whole machine. Because structural members are subjected to complex and variable cyclic loads, steel is required to have high yield strength and fatigue limit, good impact toughness and cold formability, and excellent welding performance. The engineering mechanical structural member is formed by welding plates, so that when the steel plate is selected, the high-strength steel plate is required to have excellent welding performance.
At present, Ni and Mo are added into steel for engineering machinery, for example, Zhang hong et al (Zhang hong et al, research and development of a quenched and tempered high-strength steel Q690 medium plate, hot working process, No. 12 of No. 39 in 2010) describes a quenched and tempered high-strength steel Q690, a low-carbon and Mo-Ni-B microalloying component design scheme is adopted, the manufacturing cost is increased, and the preheating temperature of the quenched and tempered high-strength steel Q690 is not mentioned; zhao Yan Qing et al (Zhao Yan Qing et al, organization and performance of 690MPa grade low carbon bainite steel after tempering, metal heat treatment, 10 th 35 th 10 th of 2010), describe a 690MPa grade low carbon bainite steel, also adopted precious metals such as Ni, Mo, etc. to improve the mechanical properties of the steel plate, resulting in increased cost; zhang Yun Yan et al (Zhang Yun Yan et al, the influence of heat treatment process on the performance of 690MPa grade high strength structural steel, iron and steel research, No. 5 of No. 35 of 10 month in 2007) introduced the differences of the chemical composition, mechanical properties, on-line heat treatment and off-line heat treatment microstructures of Q690, and also used other alloy elements such as Mo to enhance the performance of the steel plate, and did not describe the preheating temperature.
The statements in the background section are merely prior art as they are known to the inventors and do not, of course, represent prior art in the field.
Disclosure of Invention
In one aspect of the invention, the invention provides a rare earth treated high-strength steel plate with a low preheating temperature of 690MPa grade, which comprises the following chemical components in percentage by mass: c: 0.09-0.15%, Si: 0.30-0.45%, Mn: 1.58-1.75%, P is less than or equal to 0.02%, S is less than or equal to 0.010%, Nb: 0.04-0.08%, V: 0.05-0.08%, Ti: 0.010-0.020%, Cr: 0.20-0.40%, La is less than or equal to 0.030%, Alt: 0.020-0.050%, less than or equal to 0.005% of N, less than or equal to 0.004% of O, and the balance of iron and other inevitable impurities.
Preferably, the steel plate comprises the following chemical components in percentage by mass: c: 0.12%, Si: 0.375%, Mn: 1.665%, P: 0.014%, S: 0.007%, Nb: 0.06%, V: 0.065%, Ti: 0.015%, Cr: 0.40%, La: 0.020%, Alt: 0.035%, N: 0.0034%, O: 0.0018% and the balance of iron and other inevitable impurities.
Preferably, when the steel plate is welded at the preheating temperature of less than 60 ℃ in the oblique Y groove welding crack test, the surface crack rate and the section crack rate of the steel plate are both zero.
Preferably, the microstructure of the steel sheet is mainly tempered sorbite. Tempered sorbite is a tempered structure of martensite, and is a mixture of ferrite and granular carbide. Since ferrite has a substantially carbon-free supersaturation degree and carbide is also stable carbide, tempered sorbite has an equilibrium structure at normal temperature. The composite material has good toughness and plasticity, and high strength, so that the composite material has good comprehensive mechanical properties.
In another aspect of the present invention, the present invention provides a method for preparing the above rare earth treated high strength steel sheet with a low preheating temperature of 690MPa level, the method comprising the steps of: the method comprises the following steps of molten iron pretreatment, smelting, continuous casting, casting blank heating, controlled rolling, controlled cooling, straightening and heat treatment, wherein the molten iron pretreatment comprises desulfurization, decarburization and dephosphorization treatment; the smelting of the steps comprises converter smelting, external refining and RH furnace vacuum degassing; obtaining a casting blank after the continuous casting step, wherein the casting blank comprises the following chemical components in percentage by mass: c: 0.09-0.15%, Si: 0.30-0.45%, Mn: 1.58-1.75%, P is less than or equal to 0.02%, S is less than or equal to 0.010%, Nb: 0.04-0.08%, V: 0.05-0.08%, Ti: 0.010-0.020%, Cr: 0.20-0.40%, La is less than or equal to 0.030%, Alt: 0.020-0.050%, N is less than or equal to 0.005%, and O is less than or equal to 0.004%.
Preferably, the heating temperature of the casting blank in the casting blank heating step is 1200-1260 ℃.
Preferably, the controlled rolling step comprises rough rolling and finish rolling, wherein the rough rolling starting temperature is 1100-1150 ℃, the finish rolling temperature is 980-1050 ℃, the single-pass reduction rate is more than or equal to 10%, the cumulative reduction rate is more than or equal to 60%, the finish rolling is started when the thickness of the rough rolled product is 2.5-3.5 times of the thickness of the finished product, the finish rolling starting temperature is less than or equal to 950 ℃, the single-pass reduction rate is more than or equal to 12%, the cumulative reduction rate is more than or equal to 63%, and the finish rolling temperature range is 800-880 ℃.
Preferably, in the step of controlled cooling and straightening, the controlled cooling is carried out at a cooling rate of 8-17 ℃/s until the temperature is 580-640 ℃, and then a straightening machine is used for straightening.
Preferably, the heat treatment step comprises shot blasting on the surface of the steel plate, heating to 920-940 ℃, keeping the temperature for 15-25min, quenching, and keeping the temperature for 8-12 min at 500-600 ℃ for tempering.
Based on the scheme, the 690MPa high-strength steel which is added with rare earth but not Ni and Mo and has low preheating temperature is obtained, the cost is reduced, the comprehensive mechanical property is improved through rare earth treatment, the service life is prolonged, and good economic benefit is created. And passing an oblique Y groove weld crack test: when the high-strength steel is welded at the preheating temperature of less than 60 ℃, the surface crack rate and the section crack rate of the high-strength steel are zero, which shows that the 690MPa high-strength steel obtained by the invention has lower preheating temperature, and simultaneously keeps higher toughness and good welding performance. Meanwhile, the method provided by the invention adopts a wide and thick plate casting blank as a hot rolling raw material, and carries out heating, controlled rolling and controlled cooling, and heat treatment (quenching and high-temperature tempering) to finally obtain the steel plate with low welding crack sensitivity, wherein the microstructure of the steel plate is mainly tempered sorbite, and the steel plate has good comprehensive mechanical properties.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a photomicrograph of a weld specimen (preheated at 40 ℃ C.) according to example 1 of the present invention;
FIG. 2 is a photomicrograph of a weld coupon (preheated to 30 ℃ C.) according to example 1 of the present invention.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
In view of one or more problems in the prior art, an object of the present invention is to provide a 690 MPa-grade high strength steel sheet treated with rare earth having a low preheating temperature, and a method for manufacturing the same.
The object of the invention is achieved by the following specific embodiments:
in a first embodiment of the invention, the invention provides a rare earth treated high strength steel plate with a low preheating temperature of 690MPa grade, which comprises the following chemical components in percentage by mass: c: 0.09-0.15%, Si: 0.30-0.45%, Mn: 1.58-1.75%, P is less than or equal to 0.02%, S is less than or equal to 0.010%, Nb: 0.04-0.08%, V: 0.05-0.08%, Ti: 0.010-0.020%, Cr: 0.20-0.40%, La is less than or equal to 0.030%, Alt: 0.020-0.050%, less than or equal to 0.005% of N, less than or equal to 0.004% of O, and the balance of iron and other inevitable impurities. For example, the rare earth treated high-strength steel plate with a low preheating temperature of 690MPa grade comprises the following chemical components in percentage by mass: c: 0.09%, Si: 0.45%, Mn: 1.58%, P: 0.02%, S: 0.010%, Nb: 0.08%, V: 0.05%, Ti: 0.020%, Cr: 0.20%, La: 0.030%, Alt: 0.020%, N: 0.005%, O: 0.004%, and the balance of iron and other inevitable impurities; or C: 0.15%, Si: 0.30%, Mn: 1.75%, P: 0.01%, S: 0.008%, Nb: 0.08%, V: 0.05%, Ti: 0.020%, Cr: 0.20%, La: 0.020%, Alt: 0.050%, N: 0.005%, O: 0.003% and the balance of iron and other inevitable impurities; or C: 0.12%, Si: 0.40%, Mn: 1.65%, P: 0.02%, S: 0.010%, Nb: 0.06%, V: 0.06%, Ti: 0.015%, Cr: 0.30%, La: 0.025%, Alt: 0.035%, N: 0.005%, O: 0.004%, and the balance of iron and other inevitable impurities.
According to a preferred embodiment of the present invention, the steel plate comprises the following chemical components by mass percent: c: 0.12%, Si: 0.375%, Mn: 1.665%, P: 0.014%, S: 0.007%, Nb: 0.06%, V: 0.065%, Ti: 0.015%, Cr: 0.40%, La: 0.020%, Alt: 0.035%, N: 0.0034%, O: 0.0018% and the balance of iron and other inevitable impurities.
According to a preferred embodiment of the invention, when the steel plate is welded under the condition that the preheating temperature is less than 60 ℃ in the oblique Y groove welding crack test, the surface crack rate and the section crack rate of the steel plate are both zero.
According to a preferred embodiment of the invention, the microstructure of the steel plate is based on tempered sorbite. Tempered sorbite is a tempered structure of martensite, and is a mixture of ferrite and granular carbide. Since ferrite has a substantially carbon-free supersaturation degree and carbide is also stable carbide, tempered sorbite has an equilibrium structure at normal temperature. The composite material has good toughness and plasticity, and high strength, so that the composite material has good comprehensive mechanical properties.
In a second embodiment of the present invention, the present invention provides a method for producing the above rare earth treated high strength steel sheet with a low preheat temperature 690MPa level, the method comprising the steps of: the method comprises the following steps of molten iron pretreatment, smelting, continuous casting, casting blank heating, controlled rolling, controlled cooling, straightening and heat treatment, wherein the molten iron pretreatment comprises desulfurization, decarburization and dephosphorization treatment; the smelting of the steps comprises converter smelting, external refining and RH furnace vacuum degassing; after the continuous casting (electromagnetic stirring and soft reduction) step, a casting blank is obtained after cleaning, slow cooling and quality inspection, and the casting blank comprises the following chemical components in percentage by mass: c: 0.09-0.15%, Si: 0.30-0.45%, Mn: 1.58-1.75%, P is less than or equal to 0.02%, S is less than or equal to 0.010%, Nb: 0.04-0.08%, V: 0.05-0.08%, Ti: 0.010-0.020%, Cr: 0.20-0.40%, La is less than or equal to 0.030%, Alt: 0.020-0.050%, N is less than or equal to 0.005%, and O is less than or equal to 0.004%.
According to a preferred embodiment of the present invention, the slab heating temperature in the slab heating step is 1200 to 1260 ℃.
According to a preferred embodiment of the invention, the controlled rolling step comprises rough rolling and finish rolling, wherein the rough rolling start temperature is 1100-1150 ℃, the finish rolling temperature is 980-1050 ℃, the single-pass reduction rate is more than or equal to 10%, the cumulative reduction rate is more than or equal to 60%, the finish rolling is started when the thickness of the rough rolled product is 2.5-3.5 times of the thickness of the finished product, the finish rolling start temperature is less than or equal to 950 ℃, the single-pass reduction rate is more than or equal to 12%, the cumulative reduction rate is more than or equal to 63%, and the finish rolling temperature range is 800-880 ℃.
According to a preferred embodiment of the invention, in the step of controlled cooling and straightening, the controlled cooling is carried out at a cooling rate of 8-17 ℃/s to 580-640 ℃ and then is straightened by a straightener.
According to a preferred embodiment of the invention, the heat treatment step comprises shot blasting on the surface of the steel plate, heating to 920-940 ℃, keeping the temperature for 15-25min for quenching, and keeping the temperature for 8-12 min for tempering at 500-600 ℃.
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
Example 1: preparation of rare earth treated high-strength steel plate with low preheating temperature of 690MPa level
Molten iron pretreatment, smelting and continuous casting: the method comprises the steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization by adopting a top-bottom combined blown converter, carrying out LF external refining and RH furnace vacuum degassing, then carrying out continuous casting (electromagnetic stirring and soft reduction), and carrying out cleaning, slow cooling and quality inspection to obtain a casting blank.
The chemical composition of the obtained cast slab is shown in table 1 below:
TABLE 1 casting blank chemical composition and mass percent (%)
| C | Si | Mn | P | S | Alt | Nb | V | Ti | Cr | La | O | N |
| 0.09 | 0.30 | 1.58 | 0.010 | 0.005 | 0.020 | 0.040 | 0.050 | 0.010 | 0.20 | 0.010 | 0.0021 | 0.0032 |
Heating a casting blank, rolling, cooling and straightening: heating a casting blank to 1200 ℃, discharging the casting blank out of a furnace, descaling by high-pressure water, rolling, ensuring that the single-pass reduction rate is more than or equal to 10 percent at the rough rolling start temperature of 1100 ℃ and the final rolling temperature of 980 ℃, starting finish rolling when the thickness is 2.5 times of the thickness of a finished product, ensuring that the single-pass reduction rate is more than or equal to 12 percent at the finish rolling start temperature of 930 ℃, ensuring that the single-pass reduction rate is more than or equal to 12 percent at the second stage, the cumulative reduction rate of 65 percent and the final rolling temperature of 800 ℃, cooling to 580 ℃ at a cooling rate of 8 ℃/s after finish rolling.
And (3) heat treatment: after the surface quality of the steel plate is checked, performing surface shot blasting, heating the steel plate to 920 ℃, keeping the temperature for 20 minutes, quenching, and performing tempering treatment at 500 ℃ for 10 minutes.
Oblique Y groove welding crack test: the preheating temperature is 40 ℃, the welding is carried out under the condition of 30 ℃, and the detection results are shown in the following table 2. And fig. 1 and fig. 2 also show the macro photographs of the welded sample at the preheating temperature of 40 ℃ and 30 ℃ respectively, and it can be clearly seen that the surface crack rate and the section crack rate of the steel plate sample are both zero, and the welding performance is good.
TABLE 2 oblique Y groove weld crack test results
Example 2: preparation of rare earth treated high-strength steel plate with low preheating temperature of 690MPa level
Molten iron pretreatment, smelting and continuous casting: the method comprises the steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization by adopting a top-bottom combined blown converter, carrying out LF external refining and RH furnace vacuum degassing, then carrying out continuous casting (electromagnetic stirring and soft reduction), and carrying out cleaning, slow cooling and quality inspection to obtain a casting blank.
The chemical composition of the resulting cast slab is shown in table 3 below:
TABLE 3 casting blank chemical composition and mass percent (%)
| C | Si | Mn | P | S | Alt | Nb | V | Ti | Cr | La | O | N |
| 0.12 | 0.375 | 1.665 | 0.014 | 0.007 | 0.035 | 0.060 | 0.065 | 0.015 | 0.40 | 0.020 | 0.0018 | 0.0034 |
Heating a casting blank, rolling, cooling and straightening: heating the casting blank to 1230 ℃, discharging, descaling by high-pressure water, rolling, ensuring that the initial rolling temperature of rough rolling is 1125 ℃, the final rolling temperature is 1015 ℃, ensuring that the single-pass reduction rate is more than or equal to 11 percent, the cumulative reduction rate is 63 percent, starting finish rolling when the thickness is 3.0 times of the thickness of the finished product, ensuring that the initial rolling temperature of finish rolling is 930 ℃, ensuring that the single-pass reduction rate is more than or equal to 13 percent, the cumulative reduction rate is 66 percent, the final rolling temperature is 840 ℃, cooling to 610 ℃ at the cooling rate of 12.5 ℃/s after finish rolling, and then sending to a straightening machine for straightening.
And (3) heat treatment: after the surface quality of the steel plate is checked, performing surface shot blasting, heating the steel plate to 930 ℃, keeping the temperature for 20 minutes, quenching, and performing tempering treatment at 550 ℃ for 10 minutes.
Oblique Y groove welding crack test: the steel plate sample is welded at the preheating temperature of 20 ℃ and the preheating temperature of 10 ℃, the detection results are shown in the table 4, and the data in the table 4 show that the surface crack rate and the section crack rate of the steel plate sample are zero and the welding performance is good when the steel plate sample is welded at the preheating temperature of 20 ℃ and the preheating temperature of 10 ℃.
TABLE 4 oblique Y groove weld crack test results
Example 3: preparation of rare earth treated high-strength steel plate with low preheating temperature of 690MPa level
Molten iron pretreatment, smelting and continuous casting: the method comprises the steps of carrying out desulfurization pretreatment on molten iron, carrying out decarburization and dephosphorization by adopting a top-bottom combined blown converter, carrying out LF external refining and RH furnace vacuum degassing, then carrying out continuous casting (electromagnetic stirring and soft reduction), and carrying out cleaning, slow cooling and quality inspection to obtain a casting blank.
The chemical composition of the resulting cast slab is shown in table 5 below:
TABLE 5 chemical composition and mass% of casting blank
| C | Si | Mn | P | S | Alt | Nb | V | Ti | Cr | La | O | N |
| 0.15 | 0.45 | 1.75 | 0.015 | 0.010 | 0.050 | 0.080 | 0.080 | 0.02 | 0.20 | 0.015 | 0.0016 | 0.0030 |
Heating a casting blank, rolling, cooling and straightening: heating a casting blank to 1260 ℃, discharging, descaling by high-pressure water, rolling, wherein the initial rolling temperature of rough rolling is 1150 ℃, the final rolling temperature is 1050 ℃, the single-pass reduction rate is not less than 11%, the cumulative reduction rate is 63%, finish rolling is started when the thickness is 3.5 times of the thickness of a finished product, the initial rolling temperature of finish rolling is 930 ℃, the single-pass reduction rate is not less than 13%, the cumulative reduction rate is 66%, the final rolling temperature is 880 ℃, cooling to 640 ℃ at a cooling rate of 17 ℃/s after finish rolling, and then sending to a straightening machine for straightening.
And (3) heat treatment: after the surface quality of the steel plate is checked, performing surface shot blasting, heating the steel plate to 940 ℃, keeping the temperature for 20 minutes, quenching, and performing tempering treatment at 600 ℃ for 10 minutes.
Oblique Y groove welding crack test: the steel plate sample is welded at the preheating temperature of 15 ℃ and the preheating temperature of 5 ℃, the detection results are shown in the following table 6, and the data in the table 6 show that the surface crack rate and the section crack rate of the steel plate sample are zero and the welding performance is good when the steel plate sample is welded at the preheating temperature of 15 ℃ and the preheating temperature of 5 ℃.
TABLE 6 oblique Y groove weld crack test results
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. A preparation method of a rare earth treated high-strength steel plate with a low preheating temperature of 690MPa level is characterized by comprising the following steps: the method comprises the following steps of molten iron pretreatment, smelting, continuous casting, casting blank heating, controlled rolling, controlled cooling, straightening and heat treatment, wherein the molten iron pretreatment comprises desulfurization, decarburization and dephosphorization treatment; the smelting of the steps comprises converter smelting, external refining and RH furnace vacuum degassing; obtaining a casting blank after the continuous casting step; the steel plate comprises the following chemical components in percentage by mass: c: 0.09-0.15%, Si: 0.30-0.45%, Mn: 1.58-1.75%, P is less than or equal to 0.02%, S is less than or equal to 0.010%, Nb: 0.04-0.08%, V: 0.05-0.08%, Ti: 0.010-0.020%, Cr: 0.20-0.40%, La is less than or equal to 0.030%, Alt: 0.020-0.050%, N is less than or equal to 0.005%, O is less than or equal to 0.004%, and the balance of iron and other inevitable impurities;
in the step of heating the casting blank, the heating temperature of the casting blank is 1200-1260 ℃;
the controlled rolling step comprises rough rolling and finish rolling, wherein the rough rolling starting temperature is 1100-1150 ℃, the finish rolling temperature is 980-1050 ℃, the single pass reduction rate is more than or equal to 10%, the cumulative reduction rate is more than or equal to 60%, the finish rolling is started when the thickness of the rough rolled product is 2.5-3.5 times of the thickness of the finished product, the finish rolling starting temperature is less than or equal to 950 ℃, the single pass reduction rate is more than or equal to 12%, the cumulative reduction rate is more than or equal to 63%, and the finish rolling temperature range is 800-880 ℃;
in the step of controlling cooling and straightening, the controlled cooling is carried out at a cooling rate of 8-17 ℃/s to 580-640 ℃ and then a straightening machine is used for straightening;
the heat treatment step comprises shot blasting on the surface of the steel plate, heating to 920-940 ℃, keeping the temperature for 15-25min, quenching, and keeping the temperature for 8-12 min at 500-600 ℃ for tempering;
when the steel plate is welded under the condition that the preheating temperature is lower than 60 ℃ in an oblique Y groove welding crack test, the surface crack rate and the section crack rate of the steel plate are both zero;
the microstructure of the steel plate is mainly tempered sorbite.
2. The manufacturing method according to claim 1, wherein the steel plate comprises the following chemical components in percentage by mass: c: 0.12%, Si: 0.375%, Mn: 1.665%, P: 0.014%, S: 0.007%, Nb: 0.06%, V: 0.065%, Ti: 0.015%, Cr: 0.40%, La: 0.020%, Alt: 0.035%, N: 0.0034%, O: 0.0018% and the balance of iron and other inevitable impurities.
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| CN110541117B (en) * | 2019-10-16 | 2020-12-15 | 宝武集团鄂城钢铁有限公司 | 620 MPa-grade high-performance bridge steel welded at low preheating temperature and preparation method thereof |
| CN112626423A (en) * | 2020-12-15 | 2021-04-09 | 包头钢铁（集团）有限责任公司 | Production process for improving welding performance of rare earth high-strength steel |
| CN113416880A (en) * | 2021-05-28 | 2021-09-21 | 包头钢铁（集团）有限责任公司 | Preparation method of rare earth microalloyed high-corrosion-resistance 690 MPa-grade high-strength steel |
| CN114774781B (en) * | 2022-03-29 | 2023-08-25 | 包头钢铁（集团）有限责任公司 | Rare earth microalloyed 355 MPa-level fatigue-resistant offshore wind power steel and preparation method thereof |
| CN115491475B (en) * | 2022-10-12 | 2023-09-26 | 包头钢铁（集团）有限责任公司 | Preparation method of rare earth microalloyed low-cost high-hardness plastic die steel P20 |
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| CN102337455A (en) * | 2011-09-05 | 2012-02-01 | 内蒙古包钢钢联股份有限公司 | High-toughness wear-resistant steel plate formed by rare earth through treatment |
| CN102586676A (en) * | 2012-03-22 | 2012-07-18 | 内蒙古包钢钢联股份有限公司 | Rare earth-containing high-strength steel plate for manufacturing wind power tower, and rolling method of steel plate |
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