CN111172462A - 450 MPa-grade weathering steel and preparation method thereof - Google Patents
450 MPa-grade weathering steel and preparation method thereof Download PDFInfo
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
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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
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- C22C33/00—Making ferrous alloys
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- C22C33/06—Making ferrous alloys by melting using master alloys
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
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- 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
- C21D2211/002—Bainite
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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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Abstract
The invention discloses 450 MPa-grade weathering steel and a preparation method thereof, wherein the 450 MPa-grade weathering steel is compositely strengthened by low-cost chromium, nickel and copper, and niobium and titanium components are eliminated, so that a ferrite pearlite and micro bainite structure is obtained, the structure ensures that a steel plate has good strength and toughness and atmospheric corrosion resistance, and has excellent forming performance, cold bending performance, welding performance and the like.
Description
Technical Field
The invention relates to the technical field of steel preparation, and particularly provides 450 MPa-grade weathering steel and a preparation method thereof.
Background
With the development of the railway vehicle industry, the demand for high strength, light weight and thinning is higher and higher, for example, the vehicle types are C64, C76 and C80, corrosion-resistant steel with yield strength of 450MPa has been adopted, the development trend of railway vehicles tends to require steel plates with higher strength and thinner specification under the requirements of the same specification and the same strength grade, and in addition, in order to improve the service life and save the cost, the steel plates are required to have higher atmospheric corrosion resistance and seawater corrosion resistance. The method generally adopted is as follows: however, niobium and titanium are expensive and cannot be reduced in cost, because they have high costs.
In recent years, the passenger car realizes four times of great speed increase, and obvious economic benefit and social benefit are obtained. At present, the Ministry of railways further provides a new idea that the spanning development of railways in China needs to be realized, and not only passenger cars need to be accelerated, but also trucks need to be accelerated in heavy load. At present, the running speed of the truck in China is 80km/h, and the axle weight is 21 t. The American railways mainly transport cargos, wherein a large part of the railways transport ores and coal, and the axle weight is 33 t-39 t, so that the railway freight cars in China still have certain potential at present. The technical progress of the railway vehicle depends on the variety, performance and quality of steel in China to a certain extent. In the 20 th century and the 80 th years, steel structures basically made of plain carbon steel, 09Mn2 and the like, atmospheric corrosion resistant steel mainly made of 09CuPTiRe with a yield strength of 295MPa and 09CuPCrNi with a yield strength of 345MPa, and weather resistant steel in developed countries such as the United states and the like has a strength level as high as 550 MPa. Scientific experiments and application experiments prove that the corrosion resistance of the weathering steel of the chromium-nickel-copper series is about 2 times of that of common carbon steel generally, and 2-3 times of that of the weathering steel in severe environment. The weathering steel is adopted on the railway main type trucks in the years 2018, namely on the boxcars. With the establishment of main technical policies of heavy-load and speed-increasing railways, the problems of reducing the self weight of the vehicles and improving the performance of the whole vehicles by selecting high-strength and high-weather-resistance structural steel are particularly prominent and urgent.
Disclosure of Invention
In view of the above, the invention aims to provide 450 MPa-grade weathering steel and a preparation method thereof, so as to solve the problem of high cost of the existing weathering steel.
The invention provides 450 MPa-grade weathering steel on one hand, which comprises the following components in percentage by mass: c: 0.02 to 0.10%, Si: 0.10 to 0.30%, Mn: 0.90-1.50%, S: 0.0010-0.0050%, P: 0.005-0.015%, Cu: 0.10 to 0.30%, Ni: 0.05-0.20%, Al: 0.015-0.055%, Cr: 0.25 to 0.55%, O: 0.0010-0.0030% of Fe, 0.01-0.04% of Re, and the balance of Fe and other inevitable impurities.
The invention also provides a preparation method of the 450 MPa-grade weathering steel, which comprises the following steps:
1) pretreatment of molten iron
Pretreating molten iron to ensure that the mass ratio of S in the molten iron fed into the converter is less than or equal to 0.003 percent, and feeding the molten iron into the converter after completely slagging off;
2) smelting in a converter
Smelting refined scrap steel and molten iron; the converter draws carbon for one time, and avoids point blowing; tapping adopts high manganese and ferrosilicon, argon purging is carried out on a steel ladle before tapping, a tapping hole is controlled, free flow is avoided, the mass content of Als in the steel ladle is controlled to be 0.025-0.045%, ferrochrome and copper-nickel alloy are added during tapping, and the content of chromium, copper and nickel in the steel ladle meets the requirement;
3) LF refining
The LF treatment process keeps micro-positive pressure, and the N increase amount is less than or equal to 10 ppm; the LF adopts active lime and fluorite to produce reducing slag, controls the argon blowing strength and avoids the exposure of molten steel; calcium treatment is carried out by adopting calcium silicate wires, and CaSi wires are fed for 450-500 m, so that inclusions are fully spheroidized, and the product performance is improved;
4) continuous casting
Protective pouring is carried out in the whole process, argon is adopted to purge the tundish before pouring, no molten steel is exposed in the pouring process, N is strictly controlled to be absorbed at a water port, and the increase of N is controlled to be less than or equal to 5 ppm; high-alkalinity slag inclusion is adopted to facilitate the removal of inclusions in steel; in the continuous casting process, the crystallizer is fed with rare earth for treatment, and double-flow and double-line feeding is adopted to ensure that the Re content in a finished product meets the requirement; the constant drawing speed is kept in the steel casting process; the control target of the continuous casting superheat degree is not more than 30 ℃;
5) heating in a furnace
The heating temperature is more than or equal to 1250 ℃, the target tapping temperature is 1220-1260 ℃, the furnace chamber atmosphere of the heating furnace is controlled, the weak oxidizing atmosphere is ensured, so as to avoid the copper brittleness, in addition, the uniform heating temperature is ensured, and a foundation is provided for ensuring the plate shape;
6) hot continuous rolling, rolling and coiling to obtain the target steel
Selecting a 3+3 mode for control in the rough rolling pass; the rolling stability is ensured; the finishing temperature is as follows: not less than 850 ℃; the coiling temperature is less than or equal to 660 ℃, and the front-section rapid cooling is adopted in a laminar cooling mode, so that the accurate control of the final rolling and coiling temperatures is ensured.
Preferably, in step 3), the CaSi wire is fed for 450 meters.
Further preferably, in the step 4), the steel casting process is performed under a soft reduction function.
More preferably, the step 6) further comprises the step of performing small scale removal after the F1 and F2 machines.
More preferably, in step 6), the finish rolling reduction ratio is not less than 4.5.
The 450 MPa-grade weathering steel provided by the invention adopts low-cost chromium, nickel and copper composite reinforcement, and eliminates the design of niobium and titanium components, so that a ferrite pearlite and micro bainite structure with a certain content is obtained, and the structure can ensure that a steel plate has good strength and toughness and atmospheric corrosion resistance, and has excellent forming performance, cold bending performance, welding performance and the like.
The corrosion resistance principle of the 450 MPa-grade weathering steel provided by the invention is as follows:
cu is the most outstanding element for improving the weather resistance of steel, and plays a role in activating a cathode in the atmospheric corrosion process, so that an anode is passivated, the corrosion speed is reduced, the uniform dissolution of steel and the oxidation speed of Fe2+ can be accelerated, the generation of a uniform gamma-FeOOH rust layer and the conversion of the gamma-FeOOH rust layer to amorphous delta-FeOOH are promoted, a compact protective film is formed and is enriched in the protective film, and the corrosion resistance effect is achieved. Cu is also a solid solution strengthening element, which can improve the strength of steel. The Cu is hot brittle, when the continuous casting billet is heated in a furnace, oxidizing gas and steel materials generate oxidation reaction, so that the iron content of the surface layer is reduced, the Cu content is relatively increased until the Cu content exceeds the solubility in iron, and the Cu is dispersed along a grain boundary after being precipitated to form a network-shaped Cu-rich phase.
Cr and Ni are elements for improving the weather resistance of steel. Cr has a low corrosion potential and a passivation tendency; the spinel-type corrosion inhibitor is dissolved in Fe3O4, a FeO-Cr 2O3 type spinel structure appears after Cr3+ occupies the position of Fe3+, and Fe3O4 tends to be stable, so that Cr has the function of promoting the generation of spinel-type oxides, and Cu has the function of amorphizing the spinel-type oxides, which jointly promote the formation of a protective film of amorphous corrosion products. The content of Ni in the weathering steel is low, but the effect of improving the weathering resistance is better than that of other elements, meanwhile, the addition of Ni in the copper-containing steel can lead copper-nickel compounds with higher melting points to be generated among crystals, a Cu enrichment layer on the surface of the steel is converted into a Cu-Ni enrichment layer, the melting point is increased from 1083 ℃ to over 1200 ℃, and the defect of 'Cu brittleness' can be effectively prevented. In addition, Cr and Ni elements reduce the carbon content of eutectoid points and improve the stability of super-cooled austenite, so that more and finer pearlite can be obtained by the steel at the same cooling speed, and the strength of the steel is improved.
After the composite micro-alloy elements of chromium, nickel, copper and the like are added into the steel, a compact protective film with strong adhesiveness is formed on the surface of the steel, so that the corrosion is prevented from diffusing and developing inwards, and a substrate below the rust layer is protected to slow down the corrosion speed. An amorphous spinel type oxide compact layer is formed between the rust layer and the matrix, and the compact oxide film prevents oxygen and water in the air of the external environment from permeating into the steel matrix, slows down the development of rust to the depth of steel and improves the corrosion resistance of the steel.
The 450 MPa-grade weathering steel provided by the invention adopts proper chromium, nickel and copper composite reinforcement on the component design, niobium, vanadium and titanium alloy are not added, the alloy cost is lower, the molten steel is pure, and the cost is saved on the basis of ensuring excellent performance; on the aspect of mechanical property, each index meets the requirement, and the margin is sufficient; the corrosion-resistant steel has good corrosion resistance, and also has excellent forming performance, cold bending performance, welding performance and the like.
The preparation method of the 450 MPa-grade weathering steel provided by the invention can be used for producing low-alloy high-strength steel with high product of strength and elongation and good corrosion resistance by using chromium, nickel and copper composite reinforcement on the basis of canceling niobium, vanadium and titanium alloys and matching with a thermomechanical control rolling process in a certain proportion, and can realize low cost, in particular:
1) by controlling the heating temperature and the furnace atmosphere, the heating temperature is controlled to be more than or equal to 1250 ℃, the target tapping temperature is 1220-1260 ℃, high-temperature quick firing is carried out, weak oxidizing atmosphere is ensured in the furnace, the heat preservation time is shortened, the heat preservation time is 15-25 minutes, alloy elements are fully blended, high-strength steel has better plasticity and good plate shape during rolling, in addition, cracks caused by copper brittleness are avoided, and the rolling process requirements are met;
2) the finish rolling compression ratio is ensured to be 4.5 or more (not less than 4.5), the metallographic structure, the mechanical property and the physical property of a finished steel plate can be ensured, and the product quality is improved;
3) and controlling the finish rolling temperature and coiling at low temperature. The sufficient time for forming intermetallic precipitates is ensured, the crystal grains are refined, and the corrosion resistance of the steel plate can be improved while the product of strength and elongation is ensured.
The invention has the following beneficial effects:
(1) the corrosion-resistant steel produced by the process completely meets the use requirements of users with excellent performance and good corrosion resistance, and promotes the light weight and large scale of products in the field of railway vehicles;
(2) the corrosion-resistant steel produced by the technology reduces the cost of enterprises, embodies higher finished product quality and yield and has good economic benefit.
Detailed Description
The invention will be further explained with reference to specific embodiments, without limiting the invention.
The invention provides 450 MPa-grade weathering steel which comprises the following components in percentage by mass: c: 0.02 to 0.10%, Si: 0.10 to 0.30%, Mn: 0.90-1.50%, S: 0.0010-0.0050%, P: 0.005-0.015%, Cu: 0.10 to 0.30%, Ni: 0.05-0.20%, Al: 0.015-0.055%, Cr: 0.25 to 0.55%, O: 0.0010-0.0030% of Fe, 0.01-0.04% of Re, and the balance of Fe and other inevitable impurities.
The invention also provides a preparation method of the 450 MPa-grade weathering steel, which comprises the following steps:
1) pretreatment of molten iron
Pretreating molten iron to ensure that the mass ratio of S in the molten iron fed into the converter is less than or equal to 0.003 percent, and feeding the molten iron into the converter after completely slagging off;
2) smelting in a converter
Smelting refined scrap steel and molten iron; the converter draws carbon for one time, and avoids point blowing; tapping adopts high manganese and ferrosilicon, argon purging is carried out on a steel ladle before tapping, a tapping hole is controlled, free flow is avoided, the mass content of Als in the steel ladle is controlled to be 0.025-0.045%, ferrochrome and copper-nickel alloy are added during tapping, and the content of chromium, copper and nickel in the steel ladle meets the requirement;
3) LF refining
The LF treatment process keeps micro-positive pressure, and the N increase amount is less than or equal to 10 ppm; the LF adopts active lime and fluorite to produce reducing slag, controls the argon blowing strength and avoids the exposure of molten steel; calcium treatment is carried out by adopting calcium silicate wires, CaSi wires are fed for 450-500 m, preferably 500 m, so that inclusions are fully spheroidized, and the product performance is improved;
4) continuous casting
Protective pouring is carried out in the whole process, argon is adopted to purge the tundish before pouring, no molten steel is exposed in the pouring process, N is strictly controlled to be absorbed at a water port, and the increase of N is controlled to be less than or equal to 5 ppm; high-alkalinity slag inclusion is adopted to facilitate the removal of inclusions in steel; in the continuous casting process, the crystallizer is fed with rare earth for treatment, and double-flow and double-line feeding is adopted to ensure that the Re content in a finished product meets the requirement; the constant drawing speed is kept in the steel casting process; the control target of the continuous casting superheat degree is not more than 30 ℃; preferably, the steel casting process has the function of soft reduction; the continuous casting billet is subjected to hot conveying and hot charging, and the residual slab is placed in a slow cooling area in a warehouse;
5) heating in a furnace
The heating temperature is more than or equal to 1250 ℃, the target tapping temperature is 1220-1260 ℃, the furnace chamber atmosphere of the heating furnace is controlled, the weak oxidizing atmosphere is ensured, so as to avoid the copper brittleness, in addition, the uniform heating temperature is ensured, and a foundation is provided for ensuring the plate shape;
6) hot continuous rolling, rolling and coiling to obtain the target steel
Selecting a 3+3 mode for control in the rough rolling pass; load distribution of a finish rolling model is well done, and rolling stability is guaranteed; the finishing temperature is as follows: not less than 850 ℃; the coiling temperature is less than or equal to 660 ℃, the front-section quick cooling mode is adopted in the laminar cooling mode, the accurate control of the final rolling and coiling temperature is ensured, and the steel can be selectively put into F1 and F2 machines for small scale removal according to the actual condition of the surface of the strip steel.
As an improvement of the technical scheme, in the step 6), the finish rolling compression ratio is more than or equal to 4.5, so that the metallographic structure and the physical property of a finished product are improved, and the product quality is improved.
The preparation method of the 450 MPa-grade weathering steel is mainly applied to the steel for railway vehicles with high corrosion resistance, high strength, weight reduction, excellent welding performance and forming performance, adopts a mode of combining traditional components with modern technology, cancels niobium, vanadium and titanium, utilizes trace elements such as chromium, nickel, copper and the like, and partially adds carbon and manganese elements, so as to ensure high strength, simultaneously have high corrosion resistance, reduce production cost and enlarge loading capacity. The principle is as follows: the original components of chromium, nickel and copper are compositely strengthened, niobium, vanadium and titanium alloy are not added, and carbon and manganese are added to the insufficient part to be matched with the modern thermo-mechanical controlled rolling, so that refined ferrite plus pearlite and a trace bainite structure are obtained, the atmospheric corrosion resistance, the welding performance and the like of the steel can be improved while the high strength-ductility product is ensured, the strength level of the steel is 450MPa, and the problems of low strength and poor corrosion resistance in the original design can be effectively solved.
The special steel produced by the technology comprises thick steel plates, thin steel plates and the like, and is suitable for modern cold and hot processing forming, welding operation and the like.
Examples
The 450 MPa-grade weathering steel is prepared according to the following mass percentages: c: 0.02 to 0.10%, Si: 0.10 to 0.30%, Mn: 0.90-1.50%, S: 0.0010-0.0050%, P: 0.005-0.015%, Cu: 0.10 to 0.30%, Ni: 0.05-0.20%, Al: 0.015-0.055%, Cr: 0.25 to 0.55%, O: 0.0010-0.0030% of Fe, 0.01-0.04% of Re, and the balance of Fe and other inevitable impurities.
The preparation method comprises the following steps:
1) pretreatment of molten iron
Pretreating molten iron to ensure that the mass of S in the molten iron fed into the converter is less than or equal to 0.003 percent, and feeding the molten iron into the converter after slagging off and slag removing;
2) smelting in a converter
Smelting refined scrap steel and molten iron; the converter draws carbon for one time, and avoids point blowing; tapping adopts high manganese and ferrosilicon, argon purging is carried out on a steel ladle before tapping, a tapping hole is controlled, free flow is avoided, the mass content of Als in the steel ladle is controlled to be 0.025-0.045%, ferrochrome and copper-nickel alloy are added during tapping, and the content of chromium, copper and nickel in the steel ladle meets the requirement;
3) LF refining
The LF treatment process keeps micro-positive pressure, and the N increase amount is less than or equal to 10 ppm; the LF adopts active lime and fluorite to produce reducing slag, controls the argon blowing strength and avoids the exposure of molten steel; calcium treatment is carried out by adopting a calcium-silicon wire, and a CaSi wire is fed for 450 meters, so that inclusions are fully spheroidized, and the product performance is improved;
4) continuous casting
Protective pouring is carried out in the whole process, argon is adopted to purge the tundish before pouring, no molten steel is exposed in the pouring process, N is strictly controlled to be absorbed at a water port, and the increase of N is controlled to be less than or equal to 5 ppm; high-alkalinity slag inclusion is adopted to facilitate the removal of inclusions in steel; in the continuous casting process, the crystallizer is fed with rare earth for treatment, and double-flow and double-line feeding is adopted to ensure that the Re content in a finished product meets the requirement; the soft reduction function is put into the steel casting process; the constant drawing speed is kept in the steel casting process; the control target of the continuous casting superheat degree is not more than 30 ℃; hot overheating of the plate blanks, and placing the rest plate blanks in a slow cooling area in a warehouse;
5) heating in a furnace
The heating temperature is more than or equal to 1250 ℃, the target tapping temperature is 1220-1260 ℃, the furnace chamber atmosphere of the heating furnace is controlled, the weak oxidizing atmosphere is ensured, so as to avoid the copper brittleness, in addition, the uniform heating temperature is ensured, and a foundation is provided for ensuring the plate shape;
6) hot continuous rolling, rolling and coiling to obtain the steel plate
Selecting a 3+3 mode for control in the rough rolling pass; adjusting the load distribution of the finish rolling model to ensure the rolling stability; the finishing temperature is as follows: not less than 850 ℃; the coiling temperature is less than or equal to 660 ℃, and the front-section quick cooling is adopted in a laminar cooling mode, so that the accurate control of the final rolling and coiling temperature is ensured; selectively throwing the steel strip into an F1 machine or an F2 machine for small scale removal according to the actual condition of the surface of the steel strip; meanwhile, the control of the cooling water amount between the racks is optimized and adjusted, wherein in the step 6), the finish rolling compression ratio is more than or equal to 4.5, the metallographic structure and the physical property of the steel can be improved, and the quality of a final product is improved;
the following performance tests were performed on steels within the target composition range produced using the methods provided in the above examples, with the results shown in table 1:
table 1: results of Performance testing
The following 72-hour relative corrosion tests were performed on steels within the target composition range produced using the methods provided in the above examples, with the results shown in table 2:
TABLE 2 relative corrosion test results for 72 hours
The results of the performance tests on weathering steels designed for the existing niobium, titanium compositions described in the background (comparative example) are given below:
table 3: results of Performance testing
Table 4: 72 hours relative Corrosion test results
And (4) conclusion: from experimental results of examples and comparative examples, the weathering steel which is prepared by compounding low-cost chromium, nickel and copper and eliminates niobium and titanium components is superior to the original process in strengthening effect.
Claims (6)
1.450 MPa-grade weathering steel, which is characterized by comprising the following components in percentage by mass: c: 0.02 to 0.10%, Si: 0.10 to 0.30%, Mn: 0.90-1.50%, S: 0.0010-0.0050%, P: 0.005-0.015%, Cu: 0.10 to 0.30%, Ni: 0.05-0.20%, Al: 0.015-0.055%, Cr: 0.25 to 0.55%, O: 0.0010-0.0030% of Fe, 0.01-0.04% of Re, and the balance of Fe and other inevitable impurities.
2. The method for preparing 450 MPa-grade weathering steel of claim 1, characterized by comprising the following steps:
1) pretreatment of molten iron
Pretreating molten iron to ensure that the mass ratio of S in the molten iron fed into the converter is less than or equal to 0.003 percent, and feeding the molten iron into the converter after completely slagging off;
2) smelting in a converter
Smelting refined scrap steel and molten iron; the converter draws carbon for one time, and avoids point blowing; tapping adopts high manganese and ferrosilicon, argon purging is carried out on a steel ladle before tapping, a tapping hole is controlled, free flow is avoided, the mass content of Als in the steel ladle is controlled to be 0.025-0.045%, ferrochrome and copper-nickel alloy are added during tapping, and the content of chromium, copper and nickel in the steel ladle meets the requirement;
3) LF refining
The LF treatment process keeps micro-positive pressure, and the N increase amount is less than or equal to 10 ppm; the LF adopts active lime and fluorite to produce reducing slag, controls the argon blowing strength and avoids the exposure of molten steel; calcium treatment is carried out by adopting calcium silicate wires, and CaSi wires are fed for 450-500 m, so that inclusions are fully spheroidized, and the product performance is improved;
4) continuous casting
Protective pouring is carried out in the whole process, argon is adopted to purge the tundish before pouring, no molten steel is exposed in the pouring process, N is strictly controlled to be absorbed at a water port, and the increase of N is controlled to be less than or equal to 5 ppm; high-alkalinity slag inclusion is adopted to facilitate the removal of inclusions in steel; in the continuous casting process, the crystallizer is fed with rare earth for treatment, and double-flow and double-line feeding is adopted to ensure that the Re content in a finished product meets the requirement; the constant drawing speed is kept in the steel casting process; the control target of the continuous casting superheat degree is not more than 30 ℃;
5) heating in a furnace
The heating temperature is more than or equal to 1250 ℃, the target tapping temperature is 1220-1260 ℃, the furnace chamber atmosphere of the heating furnace is controlled, the weak oxidizing atmosphere is ensured, so as to avoid the copper brittleness, in addition, the uniform heating temperature is ensured, and a foundation is provided for ensuring the plate shape;
6) hot continuous rolling, rolling and coiling to obtain the target steel
Selecting a 3+3 mode for control in the rough rolling pass; the rolling stability is ensured; the finishing temperature is as follows: not less than 850 ℃; the coiling temperature is less than or equal to 660 ℃, and the front-section rapid cooling is adopted in a laminar cooling mode, so that the accurate control of the final rolling and coiling temperatures is ensured.
3. The method for preparing 450 MPa-grade weathering steel according to claim 2, characterized in that: and 3) feeding the CaSi wire for 450 meters.
4. The method for preparing 450 MPa-grade weathering steel according to claim 2, characterized in that: in the step 4), the soft reduction function is put into the steel casting process.
5. The method for preparing 450 MPa-grade weathering steel according to claim 2, characterized in that: step 6), further comprising the steps of F1 and F2 post-machine small scale removal.
6. The method for preparing 450 MPa-grade weathering steel according to claim 2, characterized in that: in the step 6), the finish rolling compression ratio is more than or equal to 4.5.
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| CN112662948A (en) * | 2020-12-09 | 2021-04-16 | 本钢板材股份有限公司 | RE-Cr-Cu composite corrosion-resistant steel and preparation method thereof |
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| CN114737132A (en) * | 2021-08-10 | 2022-07-12 | 山东盛阳金属科技股份有限公司 | N06600 iron-nickel base alloy hot continuous rolling plate coil production process |
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