CN115948697A - 500 MPa-grade weather-proof coating-free hot-rolled rod wire and rolling process thereof - Google Patents
500 MPa-grade weather-proof coating-free hot-rolled rod wire and rolling process thereof Download PDFInfo
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- 238000001816 cooling Methods 0.000 claims abstract description 25
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- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 13
- 239000000126 substance Substances 0.000 claims abstract description 12
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- 239000012535 impurity Substances 0.000 claims abstract description 7
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- 238000005728 strengthening Methods 0.000 description 4
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Abstract
The invention discloses a 500 MPa-grade weather-proof coating-free hot-rolled rod wire and a rolling process thereof, wherein the wire comprises the following chemical components in percentage by weight: c: < 0.14wt%, si:0.3 to 0.6wt%, mn: 0.5-0.75 wt%, P < 0.03wt%, S < 0.02wt%, cu:0.1 to 1.0wt%, cr: 1.0-4.5 wt%, cr/Cu = 5-11, and the balance of Fe and inevitable impurities; and microalloying can be carried out according to the actual capacity of a production line to add Nb:0.015 to 0.035wt%, V: 0.04-0.07 wt%, nb/V = 1/3-2/3; the invention can meet the requirements of cold processing, coating-free and bare wire over 25 years, adopts a brand-new super weather-resistant component system and cooperates with the technical scheme of rolling control and cooling control aiming at the deep processing requirement of the industrial rod and wire for drawing, and forms a microstructure beneficial to cold processing on the basis of meeting the weather resistance.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a weather-resistant coating-free hot-rolled rod and wire and a rolling process thereof.
Background
Industrial wire and rod material are various (such as spring steel, bridge steel, cord steel, cold heading steel, free-cutting steel, bearing steel and the like), and in order to meet different service performance requirements, hot rolled wire and rod material are often processed through a plurality of procedures (such as cold drawing, cold heading, tempering, weaving, stranding and the like), so that the requirements on the structure and the performance are strict.
Currently, the upgrading of industrial lines and bars mainly focuses on the improvement of strength grade (such as the development of cord steel from grade 70 to grade 80 and 90; and the evolution of bridge cable steel from 1860MPa to 1960MPa, 2000MPa and 2100 MPa), and the weather resistance which can prolong the service life is less concerned, which has two main reasons:
(1) The steel material mainly depends on the addition of weather-resistant elements (such as Cu, cr, ni, P and the like) to improve weather resistance, the weather-resistant elements can obviously increase the hardenability of the steel, so that abnormal structures such as bainite, martensite and the like appear in the steel, and compared with the existing micro structures of industrial wires and bars which mainly comprise ferrite and pearlite, the structures such as the bainite, the martensite and the like are not beneficial to deep processing such as drawing, cold heading and the like, so that the addition of the elements such as Cu, cr, ni, P and the like in the steel is always strictly limited to ensure the service performance of the industrial wires and the bars.
(2) In some wire and bar products with weather resistance requirements on final finished products, the high weather resistance of the finished products is often achieved by means of zinc plating, copper plating and the like, such as: galvanized steel strands, copper-plated steel cords and the like, which can effectively avoid the influence of weather-resistant alloy elements on the steel performance, but the coating process has large pollution and high energy consumption and processing cost.
The weathering steel with coating-free and long service life is becoming the development hotspot of current green steel products; at present, most of the weather-resistant steel produced at home and abroad is plates, and due to completely different deep processing flows and application scenes of wire rods and plates, hot rolled wire rods and round steel for the weather-resistant steel structure which has more continuous rolling passes, high requirements on the structure performance and large cold processing deformation are rarely reported at home.
CN108396238 discloses a wire rod for 1860 MPa-grade corrosion-resistant steel strand and a production method thereof, wherein the chemical components of the wire rod are C0.80-0.85%, si 0.15-0.35%, mn 0.60-0.70%, P is less than or equal to 0.025%, S is less than or equal to 0.015%, cr0.35-0.40%, cu0.21-0.27%, ca (40-80) x 10-4%, the continuous casting superheat degree is not more than 30 ℃, and the wire rod is electromagnetically stirred; continuously rolling into square billet of 100-200 mm; the temperature difference of the whole strip is less than or equal to 30 ℃ during rolling; controlling the initial rolling temperature, the finish rolling inlet temperature, the reduced diameter inlet temperature and the spinning temperature; the stelmor air cooling line cooling adopts a cooling speed control method of strong cooling, weak cooling and strong cooling, and the stelmor air cooling line is naturally cooled after being cooled to 500 ℃. The phi (8-13) mm wire rod produced by the method has the tensile strength of 1150-1250 MPa, the elongation of 10-16% and the area shrinkage of 18-32%, and the corrosion rate is lower than 70% of that of the YL82B wire rod for the steel strand under the condition of (23 ℃, 15 d) 5% of NaCl solution full-immersion corrosion. Although the steel wire rod is a wire rod product, the weather resistance of the steel wire rod cannot meet the requirements of long-term exposure and maintenance-free performance due to high carbon content and low Cr content.
The XG835NH steel wire rod developed by Beikoda and Shichen steel is used for producing 10.9MPa grade atmospheric corrosion resistant bolts, the steel is medium carbon alloy steel, alloy elements such as Mn, mo, cr, si and the like are added into the steel, the incubation period of austenite transformation is increased by the alloy elements, the stability of super-cooled austenite of the material is improved, but a martensite structure is easy to appear at an excessively high cooling speed after the wire rod is rolled, and the martensite structure has high strength and high hardness and is not beneficial to drawing and cold heading deep processing of the wire rod.
Currently, the weather resistance of industrial rod and wire is mainly obtained by coating processes such as zinc plating, which mainly has two problems: one of the hot galvanizing processes has large pollution and high cost; the weather-resistant layer on the surface of the second coating product is often thin and is easy to damage in the processes of transportation, installation and use, so that the corrosion-resistant effect cannot be achieved; in addition, the weathering steel is developed more fully in plates at present, but for industrial bar and wire materials which need cold drawing and large deformation, the development of the weathering industrial bar and wire materials is slow due to the obvious difference between the processing flow and the application scene of the plates.
Disclosure of Invention
The invention aims to provide a 500 MPa-grade weather-proof coating-free hot-rolled rod and a rolling process thereof, which can meet the requirements of cold processing, coating-free and over 25 years of bare use, adopt a brand-new super weather-proof component system and match with a rolling and cooling control technical scheme aiming at the deep processing requirement of industrial rod and wire for drawing, and form a microstructure beneficial to cold processing on the basis of meeting the weather resistance.
In order to achieve the purpose, the technical scheme is as follows:
a500 MPa-grade weather-resistant coating-free hot-rolled rod wire comprises the following chemical components in parts by mass:
c: < 0.14wt%, si:0.3 to 0.6wt%, mn: 0.5-0.75 wt%, P < 0.03wt%, S < 0.02wt%, cu:0.1 to 1.0wt%, cr:1.0 to 4.5wt%, cr/Cu =5 to 11, and the balance Fe and unavoidable impurities.
According to the scheme, the chemical components comprise the following components in percentage by mass:
c: < 0.14wt%, si:0.4 to 0.5wt%, mn: 0.6-0.7 wt%, P less than 0.03wt%, S less than 0.02wt%, cu:0.3 to 0.7wt%, cr: 2-3.5 wt%, cr/Cu = 7-9, and the balance of Fe and unavoidable impurities.
According to the scheme, the microalloying is carried out, and the chemical components in mass fraction further comprise Nb: 0.015-0.035 wt%, V: 0.04-0.07 wt%, nb/V = 1/3-2/3.
The rolling process of the 500 MPa-grade weather-proof coating-free hot rolled rod and wire comprises the following steps:
heating a steel billet; comprises a preheating section, a heating section and a soaking section;
rolling; low-temperature controlled rolling is adopted, and austenite is rolled without recrystallization in the whole process;
controlling cold; the wire is cooled by adopting a stelmor process; the cooling bed on the bar adopts a heat-insulating cover for slow cooling.
According to the scheme, in the billet heating process, the billet is a small square billet or a rectangular billet, and the section is (140-220 mm) × (140-220 mm); the heating temperature of the preheating section is less than or equal to 600 ℃, and the heating time is 10-15 min; the heating section is divided into a heating section 1 and a heating section 2, the heating temperature of the heating section 1 is 600-1000 ℃, the heating time is 10-15 min, the heating temperature of the heating section 2 is 1000-1200 ℃, and the heating time is 40-50 min; the heating temperature of the soaking section is 1100-1200 ℃, and the heating time is 10-20 min.
According to the scheme, the finish rolling temperature in the rolling process is 850 +/-10 ℃, the diameter reducing temperature is 840 +/-10 ℃, and the finish rolling temperature is 830 +/-10 ℃.
According to the scheme, in the controlled cooling process, the wire is cooled by adopting a stelmor process, the speed of a 0# roller way is 0.2-1 m/s, and the speed of the rest 8 groups of roller ways is increased by 3 percent (extremely poor) relative to that of the previous group of roller ways; the air volume of the 13 groups of fans is 210000m 3 And h, opening the No. 1-No. 2 fan by 5-25%, opening the heat preservation cover, ensuring the temperature of the No. 2 fan to be 650 +/-20 ℃, completely closing the No. 3-No. 13 fan, closing the heat preservation cover, and ensuring the temperature of the No. 13 fan to be more than 300 ℃.
According to the scheme, in the controlled cooling process, the temperature of a cooling bed on the bar is more than 600 ℃, a heat-preservation cover is adopted for slow cooling, and the temperature of the bar out of the heat-preservation cover is more than 330 ℃.
Compared with the prior art, the invention has the following beneficial effects:
the invention develops a 500 MPa-grade weather-proof coating-free hot-rolled rod wire and a rolling process thereof, can meet the requirements of cold machining, coating-free and over 25 years of bare use, thoroughly changes the condition of steel used for the existing galvanized rod wire products, realizes simplification (coating-free) of downstream machining processes and maintenance-free of application ends, reduces the cost of the whole process of downstream users, has good market application prospect, and is expected to comprehensively replace the existing traditional coating-free products.
Drawings
FIG. 1: example 1 hot rolled microstructure: ferrite + pearlite, 200X.
FIG. 2 is a schematic diagram: example 1 hot rolled microstructure: ferrite + pearlite, 500X.
Detailed Description
The following examples further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.
The specific embodiment provides a 500 MPa-grade weather-proof coating-free hot-rolled rod wire, which comprises the following chemical components in percentage by mass:
c: < 0.14wt%, si:0.3 to 0.6wt%, mn: 0.5-0.75 wt%, P < 0.03wt%, S < 0.02wt%, cu:0.1 to 1.0wt%, cr:1.0 to 4.5wt%, cr/Cu =5 to 11, and the balance Fe and unavoidable impurities.
In an optimized scheme, the chemical components comprise the following components in percentage by mass:
c: < 0.14wt%, si:0.4 to 0.5wt%, mn: 0.6-0.7 wt%, P < 0.03wt%, S < 0.02wt%, cu:0.3 to 0.7wt%, cr: 2-3.5 wt%, cr/Cu = 7-9, and the balance Fe and inevitable impurities.
In the optimized scheme, the method also comprises the step of carrying out micro-alloying, wherein the chemical components in mass fraction further comprise Nb:0.015 to 0.035wt%, V: 0.04-0.07 wt%, nb/V = 1/3-2/3.
The specific embodiment also provides a rolling process of the 500 MPa-grade weather-resistant coating-free hot rolled rod and wire, which comprises the following steps:
heating a steel billet; comprises a preheating section, a heating section and a soaking section;
rolling; low-temperature controlled rolling is adopted, and austenite is rolled without recrystallization in the whole process;
controlling cold; the wire is cooled by adopting a stelmor process; the cooling bed on the bar adopts a heat-insulating cover for slow cooling.
Specifically, the billet in the billet heating process is a small square billet or a rectangular billet, and the section is 140-220 mm multiplied by 140-220 mm; the heating temperature of the preheating section is less than or equal to 600 ℃, and the heating time is 10-15 min; the heating section is divided into a heating section 1 and a heating section 2, the heating temperature of the heating section 1 is 600-1000 ℃, the heating time is 10-15 min, the heating temperature of the heating section 2 is 1000-1200 ℃, and the heating time is 40-50 min; the heating temperature of the soaking section is 1100 ℃ to 1200 ℃, and the heating time is 10min to 20min.
Specifically, in the rolling process, the finish rolling temperature is 850 +/-10 ℃, the diameter reducing temperature is 840 +/-10 ℃ and the finish rolling temperature is 830 +/-10 ℃.
Specifically, in the controlled cooling process, the wire is cooled by adopting a stelmor process, the speed of a 0# roller way is 0.2-1 m/s, and the speed of the rest 8 groups of roller ways is increased by 3 percent (extremely poor) relative to the speed of the former group of roller ways; the air volume of the 13 groups of fans is 210000m 3 And h, starting the 1# to 2# fans by 5 to 25 percent, starting the heat preservation cover, ensuring the temperature of the 2# fans to be 650 +/-20 ℃, completely closing the 3# to 13# fans, closing the heat preservation cover, and ensuring the temperature of the 13# fans to be more than 300 ℃.
Specifically, in the controlled cooling process, the temperature of a cooling bed on the bar is higher than 600 ℃, the bar is slowly cooled by a heat-insulating cover, and the temperature of the bar out of the heat-insulating cover is higher than 330 ℃.
In the specific embodiment of the present invention C: carbon element is unfavorable for corrosion of steel and has influence on welding property, cold brittleness and stamping property; the carbon has the most obvious influence on the strength and the plasticity of the wire rod, the strength of the wire rod is continuously improved and the plasticity is rapidly reduced along with the increase of the carbon content, and the carbon content also influences the drawability of a final finished product. In general, the carbon content of the invention is less than 0.14wt%.
Si: silicon is an important strengthening element in steel, is favorable for corrosion resistance, can obviously improve the elastic limit of the steel wire after drawing, but the excessively high content of Si increases ferrite brittleness and is not favorable for cold heading processing. Comprehensively, the silicon content of the invention is 0.3-0.6 wt%.
Mn: manganese is combined with sulfur to generate MnS, so that the harm of sulfur is reduced, pearlite can be refined, and the strength of the steel wire is improved; however, mn is easy to segregate in steel, so that the structure and the performance are uneven, and the production cost is increased due to the excessively high Mn content; further, in weathering steels, the influence of manganese on corrosion resistance is not well recognized in academia, and most of the scholars believe that manganese improves corrosion resistance of steel to the marine atmosphere, but has little effect on corrosion resistance in the industrial atmosphere. Comprehensively considering, the manganese content of the invention is 0.5-0.75 wt%.
P: phosphorus is one of the most effective alloy elements for improving the atmospheric corrosion resistance of steel, can be uniformly dissolved in the steel, is beneficial to forming a compact protective film on the surface of the steel, and prevents the interior of the steel from being corroded by the atmosphere, and the corrosion resistance is optimal when w (P) =0.08% -0.15% in the steel generally; however, in the case of industrial wire rods requiring deep cold working, phosphorus is liable to cause cold embrittlement, which has a great influence on the quality of steel, particularly cold workability, and therefore, strict control is required. Comprehensively, the phosphorus content P of the invention is less than 0.03wt%.
S: the sulfur belongs to harmful elements in the steel, the sulfur is easy to generate hot brittleness, the steel wire drawing and heat treatment processing conditions are further deteriorated, and if the mass fraction of residual sulfur in the steel is reduced to 0.01 percent, the weather resistance of the carbon steel can be greatly improved. Comprehensively, the sulfur content S of the invention is less than 0.02wt%.
Cu: copper is a common alloy additive element for producing corrosion-resistant steel materials, cu is a metal element with a low chemical reaction speed, the strength of steel can be improved by adding Cu, and if the content of Cu is too high, the low-temperature toughness of the steel can be directly influenced. It is worth noting that the effect of copper on counteracting the deleterious effects of sulfur in steel is significant, and its effect is characterized by the higher the sulfur content in steel, the more pronounced the relative effect of copper on reducing the corrosion rate. This is because copper forms insoluble sulfides with sulfur. Comprehensively, the copper content of the invention is 0.1-1.0 wt%.
Cr: chromium is a main element for improving the weather resistance of steel, and can form a compact oxide film on the surface of the steel, improve the passivation capability of the steel and reduce the growth speed of a rust layer. However, chromium greatly increases the hardenability of steel, and excessive chromium causes formation of abnormal structures such as bainite and martensite in steel, which is disadvantageous to cold workability of steel. Comprehensively, the chromium content of the invention is 1.0-4.5 wt%.
Cr/Cu: and the weather-resistant elements of copper and chromium have a synergistic strengthening effect, and the Cr/Cu = 5-11 based on the most economic cost.
Nb, V: niobium and vanadium are common microalloy strengthening elements, austenite grains can be prevented from growing, reheated austenite grains are refined, uniformity of structure and performance is improved, production cost is obviously improved by adding excessive niobium and vanadium, and the Nb and V composite microalloy strengthening effect is superior to that of a single element. Comprehensively, the contents of niobium and vanadium are respectively 0.015-0.035 wt% and 0.04-0.07 wt%, and Nb/V = 1/3-2/3.
As a high-alloy steel grade, cracks need to be avoided in the heating process of a casting blank, so a special segmented heating process needs to be made; meanwhile, the invention is also low-carbon steel, in order to further improve the obdurability, the invention also adopts low-temperature controlled rolling and obtains a microstructure suitable for drawing through proper controlled cooling, and avoids a large amount of abnormal structures such as martensite, bainite and the like.
The chemical compositions of the examples of the present invention and the comparative examples are shown in table 1; the heating process parameters of each example and comparative example are shown in Table 2; the process parameters of the rolling process of each example and comparative example are shown in Table 3; the cooling control process parameters for each example and comparative example are shown in table 4. The test effects (toughness, cold heading property, weather resistance) of each example and comparative example are shown in Table 5.
The microstructure of example 1 is shown in figures 1 and 2, wherein figure 1 is a hot rolled microstructure: ferrite + pearlite, 200X; FIG. 2 shows a hot-rolled microstructure: ferrite + pearlite, 500X.
TABLE 1 chemical composition wt%
TABLE 2 heating Process parameters
TABLE 3 Rolling Process parameters
TABLE 4 Cooling control Process parameters
TABLE 5 test results
As can be seen from Table 5, the toughness and the corrosion resistance of the comparative examples 1 to 3 which are the current conventional products are both obviously lower than those of the examples, and the coating-free use requirements cannot be met; the 500 MPa-grade weather-proof coating-free hot rolled rod and the rolling process thereof have excellent obdurability, cold heading property and weather resistance (the relative corrosion rate is less than or equal to 25%), can meet the requirements of deep drawing and cold heading processing, can meet the requirements of cold processing, coating-free processing and over 25 years of naked use, simplify the downstream processing flow and the maintenance of an application end, reduce the whole-flow purchasing cost of downstream users, have good market application prospect, and are expected to comprehensively replace the conventional coating-type products.
Claims (8)
1. A500 MPa-grade weather-proof coating-free hot-rolled rod wire is characterized by comprising the following chemical components in percentage by mass:
c: < 0.14wt%, si:0.3 to 0.6wt%, mn: 0.5-0.75 wt%, P < 0.03wt%, S < 0.02wt%, cu:0.1 to 1.0wt%, cr:1.0 to 4.5wt%, cr/Cu =5 to 11, and the balance Fe and unavoidable impurities.
2. The 500MPa grade weathering and coating-free hot rolled rod and wire rod according to claim 1, characterized by chemical composition comprising, in mass fractions:
c: < 0.14wt%, si:0.4 to 0.5wt%, mn: 0.6-0.7 wt%, P < 0.03wt%, S < 0.02wt%, cu:0.3 to 0.7wt%, cr: 2-3.5 wt%, cr/Cu = 7-9, and the balance Fe and inevitable impurities.
3. The 500MPa grade weather resistant coating-free hot rolled rod wire rod according to claim 1, further comprising Nb: 0.015-0.035 wt%, V: 0.04-0.07 wt%, nb/V = 1/3-2/3.
4. The rolling process of the 500 MPa-grade weather-proof coating-free hot rolled rod and wire rod of any one of claims 1 to 3, characterized by comprising the following steps:
heating a steel billet; comprises a preheating section, a heating section and a soaking section;
rolling; low-temperature controlled rolling is adopted, and austenite is rolled without recrystallization in the whole process;
controlling cold; the wire is cooled by adopting a stelmor process; the bar material upper cooling bed adopts a heat-insulating cover for slow cooling.
5. The rolling process of the 500MPa class weather-resistant coating-free hot rolled rod and wire rod according to claim 4, wherein the billet in the billet heating process is a billet or a rectangular billet with a cross section of (140-220 mm) x (140-220 mm); the heating temperature of the preheating section is less than or equal to 600 ℃, and the heating time is 10-15 min; the heating section is divided into a heating section 1 and a heating section 2, the heating temperature of the heating section 1 is 600-1000 ℃, the heating time is 10-15 min, the heating temperature of the heating section 2 is 1000-1200 ℃, and the heating time is 40-50 min; the heating temperature of the soaking section is 1100-1200 ℃, and the heating time is 10-20 min.
6. The rolling process of the 500 MPa-grade weather-resistant coating-free hot rolled rod and wire rod according to claim 4, wherein the finish rolling temperature in the rolling process is 850 +/-10 ℃, the diameter reducing temperature is 840 +/-10 ℃, and the finish rolling temperature is 830 +/-10 ℃.
7. The rolling process of the 500 MPa-grade weather-resistant coating-free hot rolled rod and wire rod according to claim 4, characterized in that in the controlled cooling process, the wire rod is controlled to be cooled by a stelmor process, the speed of a 0# roller way is 0.2-1 m/s, and the speed of the rest 8 groups of roller ways is increased by 3 percent (extremely poor) relative to the speed of the former group of roller ways; the air volume of the 13 groups of fans is 210000m 3 H, starting the 1# to 2# fan by 5 to 25 percent, and opening the heat-insulating cover to ensure that the temperature of the 2# fan is 650 +/-2The temperature of the No. 3 to No. 13 fan is 0 ℃, the heat preservation cover is closed, and the temperature of the No. 13 fan is ensured to be more than 300 ℃.
8. The rolling process of the 500MPa weather-resistant coating-free hot rolled rod and wire as claimed in claim 4, wherein in the controlled cooling process, the temperature of a cooling bed on the rod is higher than 600 ℃, a heat preservation cover is adopted for slow cooling, and the temperature of the rod out of the heat preservation cover is higher than 330 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211658241.6A CN115948697B (en) | 2022-12-22 | 500 MPa-level weather-resistant coating-free hot rolled rod wire and rolling process thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211658241.6A CN115948697B (en) | 2022-12-22 | 500 MPa-level weather-resistant coating-free hot rolled rod wire and rolling process thereof |
Publications (2)
| Publication Number | Publication Date |
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| CN115948697A true CN115948697A (en) | 2023-04-11 |
| CN115948697B CN115948697B (en) | 2024-05-14 |
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| JPH07268467A (en) * | 1994-03-30 | 1995-10-17 | Nippon Steel Corp | Production of hot coil for steel tube having high toughness and sour resistance |
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| US20030098104A1 (en) * | 2000-04-04 | 2003-05-29 | Kiichiro Tsuchida | Hot rolled wire or steel bar for machine structural use capable of dispensing with annealing, and method for producing the same |
| KR20110076148A (en) * | 2009-12-29 | 2011-07-06 | 주식회사 포스코 | Hot rolled steel sheet having excellent corrosion resistance and impcat toughness and manufacturing method thereof |
| CN115161552A (en) * | 2022-06-15 | 2022-10-11 | 宝山钢铁股份有限公司 | High-strength hot-rolled strip steel with high weather resistance and manufacturing method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07268467A (en) * | 1994-03-30 | 1995-10-17 | Nippon Steel Corp | Production of hot coil for steel tube having high toughness and sour resistance |
| US20030098104A1 (en) * | 2000-04-04 | 2003-05-29 | Kiichiro Tsuchida | Hot rolled wire or steel bar for machine structural use capable of dispensing with annealing, and method for producing the same |
| KR20020040213A (en) * | 2000-11-24 | 2002-05-30 | 이구택 | A METHOD FOR MANUFACTURING HOT ROLLED STEEL SHEET OF TENSILE STRENGTH 80kg/㎟ GRADE WITH EXCELLENT WEATHER RESISTANCE AND WORKABILITY |
| KR20110076148A (en) * | 2009-12-29 | 2011-07-06 | 주식회사 포스코 | Hot rolled steel sheet having excellent corrosion resistance and impcat toughness and manufacturing method thereof |
| CN115161552A (en) * | 2022-06-15 | 2022-10-11 | 宝山钢铁股份有限公司 | High-strength hot-rolled strip steel with high weather resistance and manufacturing method thereof |
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