CN114107781A - Method for rolling 635 MPa-grade high-strength steel bars by using billet waste heat in short process - Google Patents
Method for rolling 635 MPa-grade high-strength steel bars by using billet waste heat in short process Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- 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
- B22D11/16—Controlling or regulating processes or operations
- B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
- B22D11/225—Controlling or regulating processes or operations for cooling cast stock or mould for secondary cooling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
Abstract
The invention relates to the technical field of steel processing, in particular to a method for rolling 635 MPa-grade high-strength steel bars by utilizing square billet waste heat in a short process. On the basis of the existing 635 MPa-level high-strength steel bar production process equipment level in a steel mill, through optimized design, square billets are not required to be heated by a heating furnace and are sequentially transported to a wire or bar rolling unit through a conveying roller way to be rolled, a converter/electric furnace smelting → LF furnace refining → small square billet continuous casting → wire or bar rolling machine short-process rolling method is adopted, the waste heat of the square billets is fully utilized to produce the disc-screw or straight-strip 635 MPa-level high-strength steel bars,the addition amount of the alloy is reduced by 10-20% compared with the conventional production process, and the fuel consumption is reduced. Yield strength R of the prepared steel bareLNot less than 635MPa, tensile strength RmNot less than 795MPa, the yield ratio not less than 1.25, the elongation A after fracture not less than 15%, and the total elongation A under maximum forcegt≥9.0％。
Description
Technical Field
The invention belongs to the technical field of steel processing, and particularly relates to a method for rolling 635 MPa-grade high-strength steel bars by utilizing square billet waste heat in a short process.
Background
The high-strength steel bars can reduce the workload of logistics transportation, steel bar processing and connection in the engineering construction stage, thereby saving the consumption of energy and resources such as land, coal, water, ore and the like, and reducing CO2、SO2And the emission of harmful gases and waste residues; in the using stage, the energy consumption of building heating, illumination, household appliances, ventilation and the like can be reduced, the maintenance and use cost is reduced, the reduction of the engineering cost is realized, and huge direct or indirect economic benefits are obtained. Therefore, the popularization and the application of the high-strength steel bar accord with the national policy of sustainable development proposed by China, the energy and the fuel are saved and reasonably utilized, the scientific development of engineering construction is promoted, and the high-strength steel bar has important significance for promoting the structure adjustment and transformation upgrading of the steel industry, eliminating the backward productivity and the like.
With the promulgation and implementation of GB/T1499.2-2018 '2 nd part hot rolled steel bar for reinforced concrete' in 11 months in 2018, high-strength steel bars with the grade of 600MPa and above are exemplarily applied in China, and good engineering application effects are obtained. However, the production process of the steel bars with the strength of 600MPa and above is converter/electric furnace smelting → LF furnace refining → billet continuous casting → heating furnace heating → rolling of a bar mill, and the production process needs to add a large amount of alloy in the smelting process to ensure that the steel bars obtain the yield strength of 600MPa and above. And the casting blank can be rolled only by reheating the casting blank by adopting a heating furnace, so that the cost of fuel, labor and the like of the heating furnace is increased, and the environment protection is influenced by discharged pollutants.
Disclosure of Invention
The invention aims to overcome the defects of more alloy addition and large fuel consumption in the prior art and provides a method for rolling 635 MPa-grade high-strength steel bars by utilizing billet waste heat in a short process.
In order to solve the technical problem, the technical scheme is that the method for rolling the 635 MPa-grade high-strength steel bar by using the billet waste heat in a short process comprises the following steps:
s1, weighing molten iron and scrap steel with the mass ratio of 85:15 as steelmaking raw materials, loading the scrap steel into a steelmaking furnace, then pouring the molten iron into the steelmaking furnace, converting by using a top-blown oxygen lance, finishing smelting when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1665-1685 ℃, tapping the crude molten steel, and adding a deoxidizer and an alloy into a ladle in the tapping process, wherein the addition amount of the alloy is 80-90% of that of the conventional production process;
s2, enabling the ladle to enter a refining furnace for refining, adding a slagging material, opening bottom blowing argon, controlling the total slag amount to be 1-1.2% of the total amount of the molten steel, adding 10-15kg/t of calcium carbide foaming slag after the slag material is melted, adding the calcium carbide for multiple times to prevent the calcium carbide from overflowing from a ladle opening after foaming, sampling and measuring the temperature at the later stage of refining, finely adjusting the components according to the component inspection result, and enabling the ladle to be taken out of a refining station after the molten steel reaches the set components and the temperature of 1555 and 1570 ℃;
s3, hoisting the ladle to a continuous casting platform, and casting the ladle into a steel billet, wherein the tundish temperature of the continuous casting square billet in the continuous casting process is 1520-; cooling water amount of the continuous casting crystallizer section: 150 square billet is 100-130m3165 square billet is 140-3H; cooling specific water amount of the continuous casting fan-shaped second cooling section: the volume ratio of cooling water in the 150 square billet is 1.1-1.4L/kg, the 165 square billet is 1.2-1.5L/kg, the continuous casting fan-shaped second cooling section consists of a foot roll area, a second cooling section and a second cooling section, and the cooling water volume distribution ratio of the foot roll area, the second cooling section and the second cooling section is 20:50: 15; the billet drawing speed is 3.5-4.0m/min, and during the billet drawing operation, a heat preservation cover is adopted for heat preservation, and the billet reaches the temperature of 900-950 ℃ which is suitable for rolling by a roughing mill set;
s4, the square billet is heated by a heating furnace, namely is conveyed to a wire rod rough rolling unit through a conveying roller way to roll the steel bar, the rolling temperature is 900-;
or the square billet is heated by a heating furnace, namely is conveyed to a bar rolling unit through a conveying roller way to roll the steel bar, the rolling temperature is 900-950 ℃, and then the rolling process of 6-frame rough rolling, 6-frame medium rolling and 6-frame finish rolling is adopted, so that the straight-strip 635 MPa-level high-strength steel bar is prepared.
The method for rolling the 635 MPa-level high-strength steel bar by using the billet waste heat in the short process is further improved as follows:
preferably, the steel furnace in step S1 is a converter or an electric furnace.
Preferably, when the alloy in step S1 is VN alloy, the addition amount of VN alloy in the conventional production process is 2.0kg/t steel, and the addition amount of VN alloy of the invention is 1.6-1.8kg/t steel.
Preferably, the tapping temperature of the crude steel liquid in the step S1 is 1665-1685 ℃.
Preferably, when the composition is trimmed in step S2, the amount of the trimmed material added for an element may be calculated according to the following calculation formula:
wherein, the internal control component refers to a control target value of the content of a certain element C, Si, Mn or V in the molten steel;
the molten steel components refer to the measured values of the contents of certain elements C, Si, Mn or V in the molten steel before the fine-tuning raw materials are added;
the alloy element content refers to the content of a certain element in the added fine-tuning raw material, wherein the fine-tuning raw material of the C element is a carburant, the fine-tuning raw material of the Si element is ferrosilicon, the fine-tuning raw material of the Mn element is silicomanganese, and the fine-tuning raw material of the V element is vanadium-nitrogen alloy;
the element absorption rate refers to the content of a certain element in molten steel/the addition amount of the element multiplied by 100 percent.
Preferably, the slag-making material in step S2 is one or both of wollastonite and lime.
Compared with the prior art, the invention has the beneficial effects that:
the invention adopts the billet conveying roller way, and utilizes the waste heat of the continuous casting square billet, namely the characteristics of higher square billet temperature and higher plasticity and being suitable for rolling by wire/bar rolling to convey the continuous casting square billet to the wire/bar rolling mill, thereby realizing that the continuous casting square billet can be rolled by reinforcing steel bars without being heated by a heating furnace; different from the traditional heating furnace for reheating the square billet, the surface temperature of the square billet is high, and the core temperature of the square billet is low, and the surface temperature of the square billet is lower than the core temperature, which is equivalent to that the core steel has better plasticity, is more beneficial to compression deformation and the pressing of the internal defects of the square billet, and improves the quality of the finished steel bar product; compared with the traditional heating furnace for reheating the square billet, the surface temperature of the square billet is low, which is equivalent to low initial rolling temperature, the strength index of a steel bar product can be improved, and furthermore, the addition amount of alloy can be reduced on the premise of ensuring the performance index; meanwhile, the waste heat is not heated by a heating furnace, so that the expenditure of fuel, labor and other costs can be greatly reduced.
On the basis of the existing 635 MPa-level high-strength steel bar production process equipment level in a steel mill, the invention adopts converter/electric furnace smelting → LF furnace refining → billet continuous casting → wire/bar mill rolling by optimized design. The converter/electric furnace smelting and LF furnace refining can be carried out according to the conventional production process, but the addition amount of the alloy is reduced by 10-20% compared with the conventional production process, the fuel consumption is saved, and the labor cost is about 120 yuan/ton of steel bar.
Drawings
FIG. 1 is a flow chart of the wire rolling process of 635MPa grade high strength steel bar of the present invention;
FIG. 2 is a flow chart of rolling a 635MPa grade high-strength steel bar according to the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to embodiments, and all other embodiments obtained by a person of ordinary skill in the art without any creative effort based on the embodiments of the present invention belong to the protection scope of the present invention.
Comparative example
(1) Smelting in a converter, finishing smelting and tapping when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1700 ℃, deoxidizing and alloying in a steel ladle in the tapping process, wherein the addition amount of vanadium-nitrogen alloy is 2.0kg/t, and refining in an LF furnace;
(2) refining the steel ladle in an LF furnace, starting bottom blowing inert gas, starting an electrode for heating, adding a slag making material for making white slag, sampling, inspecting and finely adjusting components after the set heating time and temperature are reached, so that the requirements of the components of the steel bar are met, discharging the steel ladle out of a refining station at the discharge temperature of 1560 ℃, and discharging the steel ladle out of the refining station;
(3) hoisting the steel ladle to a continuous casting table, continuously casting 150 square billets, wherein in the casting process, the steel ladle, the tundish and the crystallizer are all subjected to whole-process protective casting, the temperature of molten steel of the tundish is 1550 ℃, the straightening temperature is not less than 950 ℃, and the working casting speed is 2.5m/min to obtain continuously cast steel billets; the steel billet comprises the following chemical components in parts by weight: 0.25% of C, 0.80% of Si, 1.60% of Mn, 0.024% of P, 0.014% of S, 0.15% of V, 0.02% of Nb, 0.15% of Cr, 0.019% of N, and the balance of Fe and inevitable impurity elements;
(4) and (2) feeding the continuously cast steel billet into a heating furnace, heating to 1150 ℃ in the heating furnace, preserving heat for 70min, rolling the steel billet from the heating furnace to the required specification after rough rolling, intermediate rolling and final rolling, wherein the final rolling temperature is 1050 plus one grade of 1100 ℃, cooling by controlling after final rolling, and the temperature of an upper cooling bed is 940 ℃ to prepare a common steel bar sample.
Example 1
(1) Smelting in a converter, ending smelting and tapping when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1700 ℃, deoxidizing and alloying in a steel ladle in the tapping process, wherein the addition of vanadium-nitrogen alloy is 1.8kg/t, is reduced by 10% compared with the addition of 2.0kg/t in the conventional production process, and entering an LF furnace for refining;
(2) refining the steel ladle in an LF furnace, starting bottom blowing inert gas, starting an electrode for heating, adding a slag making material for making white slag, sampling, inspecting and finely adjusting components after the set heating time and temperature are reached, so that the requirements of the components of the steel bar are met, discharging the steel ladle out of a refining station at the discharge temperature of 1560 ℃, and discharging the steel ladle out of the refining station;
(3) hoisting the ladle to a continuous casting platform, continuously casting 150 square billets, controlling the temperature of the tundish to 1520 ℃ and the cooling water amount of the crystallizer to be 100m3The cooling water amount of the fan-shaped second cooling section is 1.1L/kg, and the foot roll area is as follows: secondary cooling and first stage: a second cooling section: the water distribution ratio of the secondary cooling section to the third cooling section is 20%: 50%: 15%: 15 percent, the blank drawing speed is 3.5m/min, and a heat preservation cover is adopted to preserve heat during the blank drawing operation of the square blank;
(4) and (3) conveying the square billet to a wire rod rough rolling unit through a conveying roller way, rolling at the beginning temperature of 900 ℃, and then adopting a rolling process of 8-frame rough rolling, 4-frame medium rolling, 4-frame pre-finish rolling and 10-frame finish rolling to prepare a disc-screw 635 MPa-grade high-strength steel bar sample 1.,
example 2:
(1) smelting in a converter, ending smelting and tapping when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1700 ℃, deoxidizing and alloying in a steel ladle in the tapping process, wherein the addition of vanadium-nitrogen alloy is 1.6kg/t, is reduced by 20% compared with the conventional production process of 2.0kg/t, and enters an LF furnace for refining;
(2) refining the steel ladle in an LF furnace, starting bottom blowing inert gas, starting an electrode for heating, adding a slag making material for making white slag, sampling, inspecting and finely adjusting components after the set heating time and temperature are reached, so that the requirements of the components of the steel bar are met, discharging the steel ladle out of a refining station at the discharge temperature of 1560 ℃, and discharging the steel ladle out of the refining station;
(3) hoisting the ladle to a continuous casting platform, continuously casting 150 square billets, controlling the temperature of the tundish to 1520 ℃ and the cooling water amount of the crystallizer to be 140m3The cooling water amount of the fan-shaped second cooling section is 1.2L/kg, and the foot roll area is as follows: secondary cooling and first stage: a second cooling section: the water distribution ratio of the secondary cooling section to the third cooling section is 20%: 50%: 15%: 15 percent, the blank drawing speed is 3.5m/min, and a heat preservation cover is adopted to preserve heat during the blank drawing operation of the square blank;
(4) and (3) conveying the square billet to a wire rod rough rolling unit through a conveying roller way, rolling at the beginning temperature of 900 ℃, and then adopting a rolling process of 8-frame rough rolling, 4-frame medium rolling, 4-frame pre-finish rolling and 10-frame finish rolling to prepare a disc-screw 635 MPa-grade high-strength steel bar sample 2.
Example 3:
(1) smelting in a converter, ending smelting and tapping when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1700 ℃, deoxidizing and alloying in a steel ladle in the tapping process, wherein the addition of vanadium-nitrogen alloy is 1.7kg/t, is reduced by 15% compared with the conventional production process, and entering an LF furnace for refining;
(2) refining the steel ladle in an LF furnace, starting bottom blowing inert gas, starting an electrode for heating, adding a slag making material for making white slag, sampling, inspecting and finely adjusting components after the set heating time and temperature are reached, so that the requirements of the components of the steel bar are met, discharging the steel ladle out of a refining station at the discharge temperature of 1560 ℃, and discharging the steel ladle out of the refining station;
(3) hoisting the ladle to a continuous casting platform, continuously casting 150 square billets, wherein the temperature of a tundish is 1550 ℃, and the cooling water amount of a crystallizer is 130m3The cooling water amount of the fan-shaped second cooling section is 1.4L/kg, and the foot roll area is as follows: secondary cooling and first stage: a second cooling section: the water distribution ratio of the secondary cooling section to the third cooling section is 20%: 50%: 15%: 15 percent, the blank drawing speed is 4.0m/min, and a heat preservation cover is adopted to preserve heat during the blank drawing operation of the square blank;
(4) the square billet is heated by a heating furnace, namely is conveyed to a bar rolling unit through a conveying roller way to roll the steel bar, the rolling temperature is 900-.
Example 4:
(1) smelting in a converter, ending smelting and tapping when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1700 ℃, deoxidizing and alloying in a steel ladle in the tapping process, wherein the addition of vanadium-nitrogen alloy is 1.6kg/t, is reduced by 20% compared with the conventional production process of 2.0kg/t, and enters an LF furnace for refining;
(2) refining the steel ladle in an LF furnace, starting bottom blowing inert gas, starting an electrode for heating, adding a slag making material for making white slag, sampling, inspecting and finely adjusting components after the set heating time and temperature are reached, so that the requirements of the components of the steel bar are met, discharging the steel ladle out of a refining station at the discharge temperature of 1560 ℃, and discharging the steel ladle out of the refining station;
(3) hoisting the ladle to a continuous casting table, continuously casting 165 square billets, wherein the temperature of a tundish is 1550 ℃, and the cooling water amount of a crystallizer is 160m3The cooling water amount of the fan-shaped second cooling section is 1.4L/kg, and the foot roll area is as follows: secondary cooling and first stage: a second cooling section: the water distribution ratio of the secondary cooling section to the third cooling section is 20%: 50%: 15%: 15 percent, the blank drawing speed is 3.5m/min, and a heat preservation cover is adopted to preserve heat during the blank drawing operation of the square blank;
(4) the square billet is heated by a heating furnace, namely is conveyed to a bar rolling unit through a conveying roller way to roll the steel bar, the rolling temperature is 900-.
The yield strength R of the steel bar samples 1-4 is testedeLNot less than 635MPa, tensile strength RmNot less than 795MPa, the yield ratio not less than 1.25, the yield ratio not less than 1.0, the elongation A after fracture not less than 15%, and the total elongation A under maximum forcegt≥9.0％。
It should be understood by those skilled in the art that the foregoing is only illustrative of several embodiments of the invention, and not of all embodiments. It should be noted that many variations and modifications are possible to those skilled in the art, and all variations and modifications that do not depart from the gist of the invention are intended to be within the scope of the invention as defined in the appended claims.
Claims (6)
1. A method for rolling 635 MPa-level high-strength steel bars by using billet waste heat in a short process is characterized by comprising the following steps:
s1, weighing molten iron and scrap steel with the mass ratio of 85:15 as steelmaking raw materials, loading the scrap steel into a steelmaking furnace, then pouring the molten iron into the steelmaking furnace, converting by using a top-blown oxygen lance, finishing smelting when the weight content of C in crude molten steel is more than or equal to 0.06%, the weight content of P and S is less than or equal to 0.025%, and the temperature is 1665-1685 ℃, tapping the crude molten steel, and adding a deoxidizer and an alloy into a ladle in the tapping process, wherein the addition amount of the alloy is 80-90% of that of the conventional production process;
s2, enabling the ladle to enter a refining furnace for refining, adding a slagging material, opening bottom blowing argon, controlling the total slag amount to be 1-1.2% of the total amount of the molten steel, adding 10-15kg/t of calcium carbide foaming slag after the slag material is melted, adding the calcium carbide for multiple times to prevent the calcium carbide from overflowing from a ladle opening after foaming, sampling and measuring the temperature at the later stage of refining, finely adjusting the components according to the component inspection result, and enabling the ladle to be taken out of a refining station after the molten steel reaches the set components and the temperature of 1555 and 1570 ℃;
s3, hoisting the ladle to a continuous casting platform, and casting the ladle into a steel billet, wherein the tundish temperature of the continuous casting square billet in the continuous casting process is 1520-; cooling water amount of the continuous casting crystallizer section: 150 square billet is 100-130m3165 square billet is 140-3H; cooling specific water amount of the continuous casting fan-shaped second cooling section: the volume ratio of cooling water in the 150 square billet is 1.1-1.4L/kg, the 165 square billet is 1.2-1.5L/kg, the continuous casting fan-shaped second cooling section consists of a foot roll area, a second cooling section and a second cooling section, and the cooling water volume distribution ratio of the foot roll area, the second cooling section and the second cooling section is 20:50: 15; the billet drawing speed is 3.5-4.0m/min, and during the billet drawing operation, a heat preservation cover is adopted for heat preservation, and the billet reaches the temperature of 900-950 ℃ which is suitable for rolling by a roughing mill set;
s4, the square billet is heated by a heating furnace, namely is conveyed to a wire rod rough rolling unit through a conveying roller way to roll the steel bar, the rolling temperature is 900-;
or the square billet is heated by a heating furnace, namely is conveyed to a bar rolling unit through a conveying roller way to roll the steel bar, the rolling temperature is 900-950 ℃, and then the rolling process of 6-frame rough rolling, 6-frame medium rolling and 6-frame finish rolling is adopted, so that the straight-strip 635 MPa-level high-strength steel bar is prepared.
2. The method for short-process rolling of 635MPa grade high-strength steel bars by using the billet residual heat according to claim 1, wherein the steel-making furnace in the step S1 is a converter or an electric furnace.
3. The method for rolling the 635MPa grade high-strength steel bar by using the billet residual heat in the short process according to claim 1, wherein when the alloy in the step S1 is the VN alloy, the addition amount of the VN alloy in the conventional production process is 2.0kg/t steel, and the addition amount of the VN alloy in the invention is 1.6-1.8kg/t steel.
4. The method for short-process rolling of 635MPa grade high-strength steel bars by using billet waste heat as claimed in claim 1, wherein the tapping temperature of the crude steel liquid in the step S1 is 1665-1685 ℃.
5. The method for short-process rolling of 635MPa grade high-strength steel bars by using billet waste heat according to claim 1, wherein when the components are finely adjusted in step S2, the addition amount of fine-adjustment raw materials of certain elements can be calculated according to the following calculation formula:
wherein, the internal control component refers to a control target value of the content of a certain element C, Si, Mn or V in the molten steel;
the molten steel components refer to the measured values of the contents of certain elements C, Si, Mn or V in the molten steel before the fine-tuning raw materials are added;
the alloy element content refers to the content of a certain element in the added fine-tuning raw material, wherein the fine-tuning raw material of the C element is a carburant, the fine-tuning raw material of the Si element is ferrosilicon, the fine-tuning raw material of the Mn element is silicomanganese, and the fine-tuning raw material of the V element is vanadium-nitrogen alloy;
the element absorption rate refers to the content of a certain element in molten steel/the addition amount of the element multiplied by 100 percent.
6. The method for short-process rolling of 635MPa grade high-strength steel bars by using billet waste heat according to claim 1, wherein the slag-forming material in step S2 is one or two of wollastonite and lime.
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| CN202111330471.5A CN114107781A (en) | 2021-11-11 | 2021-11-11 | Method for rolling 635 MPa-grade high-strength steel bars by using billet waste heat in short process |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115198197A (en) * | 2022-08-22 | 2022-10-18 | 安徽吾兴新材料有限公司 | 640 MPa-grade high-strength anti-seismic reinforcing steel bar and preparation method thereof |
| CN116984373A (en) * | 2023-09-27 | 2023-11-03 | 陕西钢铁集团有限公司 | Economical green production method of high-strength shock-resistant deformed steel bar |
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| CN205308952U (en) * | 2016-01-08 | 2016-06-15 | 中冶赛迪工程技术股份有限公司 | Line rod continuous casting and rolling production line |
| CN111270127A (en) * | 2018-12-04 | 2020-06-12 | 魏滔锴 | Steel for 635MPa grade high-strength hot-rolled steel bar |
| CN112111687A (en) * | 2020-08-28 | 2020-12-22 | 安徽吾兴新材料有限公司 | Ti microalloyed 635 MPa-grade hot-rolled ribbed steel bar and preparation method thereof |
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| CN205308952U (en) * | 2016-01-08 | 2016-06-15 | 中冶赛迪工程技术股份有限公司 | Line rod continuous casting and rolling production line |
| CN111270127A (en) * | 2018-12-04 | 2020-06-12 | 魏滔锴 | Steel for 635MPa grade high-strength hot-rolled steel bar |
| CN112111687A (en) * | 2020-08-28 | 2020-12-22 | 安徽吾兴新材料有限公司 | Ti microalloyed 635 MPa-grade hot-rolled ribbed steel bar and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115198197A (en) * | 2022-08-22 | 2022-10-18 | 安徽吾兴新材料有限公司 | 640 MPa-grade high-strength anti-seismic reinforcing steel bar and preparation method thereof |
| CN116984373A (en) * | 2023-09-27 | 2023-11-03 | 陕西钢铁集团有限公司 | Economical green production method of high-strength shock-resistant deformed steel bar |
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