CN112779460A - Production method of HRB500E fine-grain high-strength anti-seismic anti-corrosion reinforcing steel bar - Google Patents
Production method of HRB500E fine-grain high-strength anti-seismic anti-corrosion reinforcing steel bar 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
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- 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
- B21B1/16—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 wire rods, bars, merchant bars, rounds wire or material of like small cross-section
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- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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Abstract
The invention discloses a production method of HRB500E fine-grain high-strength anti-seismic and anti-rust steel bars, which comprises the following steps of converter smelting, deoxidation alloying, LF furnace refining, square billet continuous casting, billet heating, rolling and cooling in sequence to produce the fine-grain high-strength anti-seismic and anti-rust steel bars with stable quality, excellent ductility and toughness, a yield ratio of more than 1.27 and a ferrite grain size of 11.5-12.0. The invention adopts Cr, V and Ni composite microalloying process, adopts converter smelting and LF external refining, combines finishing and promotes the formation and precipitation of fine and dispersed microalloy carbon (nitride) second phase by a rolling technology of controlling the inner diameter and negative deviation of the steel bar at low temperature, obviously improves the ductility and toughness while improving the steel strength, is beneficial to mechanical connection, realizes reasonable matching of high strength, obdurability, low strain timeliness, shock resistance and corrosion resistance of the steel bar, and can be applied to the fields of dry flow hydropower station cave-discharging engineering, highway flood bridge engineering and the like.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a production method for producing HRB500E fine-grain high-strength anti-seismic and anti-rust reinforcing steel bars with reasonable matching of high strength, toughness, low strain timeliness, shock resistance and corrosion resistance.
Background
With the development of basic engineering such as energy and traffic, the construction of hydropower stations, high-speed railways and highways is gradually promoted to severe environment areas such as plateaus and mountainous areas, dams, high bridges and the like with high construction difficulty and requirements are gradually increased, and the requirements for building materials such as reinforcing steel bars and the like used by the dams, the high bridges and the like are also increasingly severe. For example, a hydropower station hub mainly comprises a dam, a flood discharge system, a water diversion power generation plant and the like, and the general flood discharge system has a special structure, has a certain spraying angle (23-33 degrees) and is subjected to 4000-12500 m3The flow rate per second and the flow speed of 30-47 m/s. Therefore, the quality requirement of the steel used is very high under the influence of factors such as geology, atmospheric environment (acid rain), special structural design and the like, which need to bear complex alternating stress during working. And for dams of hydropower stations, flood protection tunnel projects and the like, large-size HRB500 high-strength steel bars with the diameter of 36-40 mm are required, and a mechanical (namely sleeve) connection mode is required in the construction process. Because the large-specification HRB500 high-strength steel bar has a large cross section, the rolling compression ratio from a casting blank to the steel bar is small, the composition difference from the surface to the center of the steel bar is large, and the cooling rate difference from the surface of a rolled piece to the center of the rolled piece is large in the rolling process and after rolling, the microstructure difference from the surface to the center of the steel bar is large, the performance difference is also large, the performance of the steel bar is unqualified frequently, and the performance qualified rate is low.
At present, in order to improve the strength and reduce the production cost, the high-strength steel bars in the market adopt different microalloying elements, different rolling process parameters and different controlled cooling modes after rolling, and the presented steel bars have different qualities: the production is carried out by adopting a high-cost hot rolling process, a strong cooling control (namely water penetration) process after rolling, a weak cooling control process and the like. But also has the problems that the production cost is high by adopting an V, Nb microalloying hot rolling process, the initial rolling temperature must reach more than 1100 ℃, and the production is carried out by adopting a post-rolling forced cooling process, so that the metallographic structure has tempered martensite, the yield strength is lower than the HRB500E standard requirement, and the compact iron scale structure formed by hot rolling can be damaged by rapid cooling after rolling, so that the short-term corrosion phenomenon of the steel bar can be caused; although the production cost of the post-rolling weak controlled cooling process is low, the temperature fluctuation of a cooling bed on a rolled piece is large, the process is difficult to operate, so that the strip passing performance of the steel bar is unstable, and the high-performance construction requirement is difficult to meet.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a production method for producing the HRB500E fine-grain high-strength anti-seismic and anti-rust reinforcing steel bar with reasonable matching of high strength, toughness, low strain aging property, shock resistance and corrosion resistance.
The purpose of the invention is realized as follows: the method comprises the working procedures of converter smelting, deoxidation alloying, LF furnace refining, square billet continuous casting, billet heating, rolling and cooling, and the specific working procedures comprise:
A. smelting in a converter: adding molten iron, scrap steel and pig iron into a converter to carry out top-bottom combined blowing, adding lime, dolomite and magnesite balls according to a conventional amount for slagging, and controlling the end point carbon content to be 0.08-0.12 wt% and the tapping temperature to be 1620-1660 ℃; lime and refining slag are added to the bottom of the ladle for slag washing before tapping, and a whole-process bottom argon blowing process is adopted during tapping;
B. and (3) deoxidation alloying: tapping the molten steel smelted in the step A, and when the molten steel amount in the steel ladle is more than 1/4, sequentially adding silicon-calcium-barium, silicon-iron, high-carbon ferromanganese, high-carbon ferrochrome, ferronickel and vanadium-nitrogen alloy into the steel ladle until the molten steel amount in the steel ladle reaches 3/4;
C. refining in an LF furnace: and (3) hoisting the molten steel after the step B to an LF furnace, blowing argon by adopting a small argon amount, then melting slag by a lower electrode, controlling the slag alkalinity to be 5.0-7.0, then heating the molten steel to 1540-1550 ℃, feeding a calcium silicate wire, performing soft argon blowing on the molten steel by adopting a small argon amount after the wire feeding is finished, and then adding a molten steel covering agent to finish refining to obtain the molten steel with the following components:
0.21 to 0.24 wt% of C, 0.48 to 0.54 wt% of Si, 1.34 to 1.40wt% of Mn, less than or equal to 0.035wt% of S, less than or equal to 0.025wt% of P, 0.230 to 0.245wt% of Cr, 0.080 to 0.100wt% of Ni, 0.100 to 0.112wt% of V, and the balance of Fe and inevitable impurities;
D. and (3) square billet continuous casting: casting the molten steel into a steel billet by the tundish obtained in the step C under the conditions that the temperature is 1535-1545 ℃, the pulling speed is 2.3-2.5 m/min and the crystallizer is electromagnetically stirred;
E. heating a steel billet: heating the billet obtained in the step D to 990-1020 ℃ in a hearth of a micro-positive pressure heating furnace at a hot charging temperature of 600-650 ℃;
F. rolling: and E, rolling the billet heated in the step E at a start rolling temperature of 980-1010 ℃ and a finish rolling temperature of 1000-1020 ℃ by adopting a flat/cross alternative rolling method:
G. and (3) cooling: and F, air cooling the steel after the finish rolling in the step F, then cutting the steel to length, bundling and stacking the steel for cooling to obtain the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar.
The invention has the beneficial effects that:
1. the invention adopts a special V, Cr and Ni composite micro-alloying process: by adding the vanadium-nitrogen alloy, the cost is reduced compared with the vanadium-iron microalloy, and V is added into the steel, so that the crystal grains are mainly refined, and V (C, N) high-temperature particles are formed, and the strength is improved; cr is added into the steel, so that the strength and the hardness of the steel can be improved, and the corrosion resistance of the steel is improved; proper amount of Cr and V are added into the steel in a matching way, so that pearlite transformation can be remarkably delayed, the pearlite content in the steel is increased by 3.0-5.0%, and fine grain strengthening is remarkable, so that the anti-seismic performance of the steel is improved; the Ni is added into the steel, so that the strength of the steel can be improved without reducing the plasticity of the steel, and the low-temperature toughness of the steel is improved; ni can enlarge an austenite region and is an effective element for austenitizing; the critical cooling speed of the steel can be reduced, and the hardenability of the steel is improved; and Ni has certain corrosion resistance and good corrosion resistance to atmosphere of some reducing acids, and a proper amount of small amount of Ni is mainly formed in solid solution in the steel, so that the strength of the steel can be improved.
2. The invention adopts converter smelting and LF external refining: the components of the molten steel can be accurately adjusted by adopting LF external refining, so that the component fluctuation of steel of different heats is small, and the performance of the finished steel bar is stable; meanwhile, inclusions in the steel can be removed in the refining process, so that the quality of the steel is improved, and the defect that the central inclusions are not easy to be rolled and scattered due to the large specification of finished steel bars is avoided; the LF furnace can also heat the molten steel, and can accurately control the temperature of the molten steel, so that the temperature of the molten steel is stable during continuous casting, and the defects of a casting blank are reduced to improve the quality of the casting blank.
3. According to the invention, the steel billet before the steel rolling link is heated to 990-1020 ℃ by adopting a reducing atmosphere heating furnace, so that an excessively high heating temperature is not required, the production cost is reduced, the surface decarburization of the steel billet can be effectively avoided, the quality control during rolling is facilitated, coarse V compounds formed in the continuous casting cooling process can be dissolved into the steel as much as possible, and the performance reduction caused by coarse microstructure of the steel bar after subsequent rolling due to coarse austenite grains caused by too high temperature can be avoided.
4. The invention adopts a low-temperature rolling technology different from the conventional technology: the initial rolling temperature is 980-1010 ℃, the rolled steel bars are cooled in an air cooling mode, and intermediate cooling and rapid cooling after rolling are not needed in the rolling process. The low-temperature rolling can promote the formation and the precipitation of fine and dispersed second phases of microalloy carbon (nitride), so that the strength of the steel is improved, and the ductility and toughness are obviously improved; the compact hot-rolled iron scale structure formed during rolling can be reserved by air cooling, so that the steel bar is not easy to rust; the temperature of the upper cooling bed after air cooling and rolling is controlled to be 1000-1020 ℃, compared with strong cooling, the difference of the internal cooling speed and the external cooling speed of the steel bar is small, the difference of the internal microstructure and the external microstructure of the steel bar is small, and the difference of the internal mechanical property and the external mechanical property of the steel bar is small, so that the overall performance of the steel bar is improved; the cold bed air cooling is gone up to rolling back, can also make things convenient for the collection packing of follow-up finishing, avoids high temperature to collect.
5. The invention controls the inner diameter of the steel bar according to d +/-0.20 mm and the negative deviation of the weight of the steel bar to be-1% -3% in the steel rolling link, and uses a forming blade with a round hole shape to cut to length and finish after cooling, thereby avoiding the flattening deformation of the cut end and being beneficial to the mechanical connection during construction.
6. The physical properties of the fine-grained high-strength anti-seismic and anti-rust reinforcing steel bar with the diameter of 40mm HRB500E obtained by the invention are shown in Table 1.
TABLE 1 physical properties of 40mm phi HRB500E fine-grained high-strength aseismic corrosion-resistant steel bar
In conclusion, the steel bar produced by the invention realizes reasonable matching of high strength, obdurability, low strain timeliness, shock resistance and corrosion resistance, and has the advantages of lower production cost, strong process applicability, reliable operation, overall controllable product quality and the like.
Detailed Description
The present invention is further illustrated by the following examples, but is not limited thereto in any way, and any modification or improvement based on the teaching of the present invention is within the scope of the present invention.
The invention comprises the working procedures of converter smelting, deoxidation alloying, LF furnace refining, square billet continuous casting, billet heating, rolling and cooling, and the specific working procedures comprise:
A. smelting in a converter: adding molten iron, scrap steel and pig iron into a converter to carry out top-bottom combined blowing, adding lime, dolomite and magnesite balls according to a conventional amount for slagging, and controlling the end point carbon content to be 0.08-0.12 wt% and the tapping temperature to be 1620-1660 ℃; lime and refining slag are added to the bottom of the ladle for slag washing before tapping, and a whole-process bottom argon blowing process is adopted during tapping;
B. and (3) deoxidation alloying: tapping the molten steel smelted in the step A, and when the molten steel amount in the steel ladle is more than 1/4, sequentially adding silicon-calcium-barium, silicon-iron, high-carbon ferromanganese, high-carbon ferrochrome, ferronickel and vanadium-nitrogen alloy into the steel ladle until the molten steel amount in the steel ladle reaches 3/4;
C. refining in an LF furnace: and (3) hoisting the molten steel after the step B to an LF furnace, blowing argon by adopting a small argon amount, then melting slag by a lower electrode, controlling the slag alkalinity to be 5.0-7.0, then heating the molten steel to 1540-1550 ℃, feeding a calcium silicate wire, performing soft argon blowing on the molten steel by adopting a small argon amount after the wire feeding is finished, and then adding a molten steel covering agent to finish refining to obtain the molten steel with the following components:
0.21 to 0.24 wt% of C, 0.48 to 0.54 wt% of Si, 1.34 to 1.40wt% of Mn, less than or equal to 0.035wt% of S, less than or equal to 0.025wt% of P, 0.230 to 0.245wt% of Cr, 0.080 to 0.100wt% of Ni, 0.100 to 0.112wt% of V, and the balance of Fe and inevitable impurities;
D. and (3) square billet continuous casting: casting the molten steel into a steel billet by the tundish obtained in the step C under the conditions that the temperature is 1535-1545 ℃, the pulling speed is 2.3-2.5 m/min and the crystallizer is electromagnetically stirred;
E. heating a steel billet: heating the billet obtained in the step D to 990-1020 ℃ in a hearth of a micro-positive pressure heating furnace at a hot charging temperature of 600-650 ℃;
F. rolling: and E, rolling the billet heated in the step E at a start rolling temperature of 980-1010 ℃ and a finish rolling temperature of 1000-1020 ℃ by adopting a flat/cross alternative rolling method:
G. and (3) cooling: and F, air cooling the steel after the finish rolling in the step F, then cutting the steel to length, bundling and stacking the steel for cooling to obtain the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar.
The molten iron in the step A comprises the following components: 4.0-5.0 wt% of C, 0.30-0.55 wt% of Si, 0.30-0.60 wt% of Mn, 0.080-0.120 wt% of P, less than or equal to 0.045wt% of S, and the balance of Fe and inevitable impurities; the steel scrap comprises the following components: 0.12 to 0.20wt% of C, 0.15 to 0.35 wt% of Si, 0.35 to 0.65wt% of Mn, 0.025 to 0.040wt% of P, 0.025 to 0.040wt% of S, and the balance of Fe and inevitable impurities; the pig iron comprises the following components: 3.0 to 3.5wt% of C, 0.30 to 0.55wt% of Si, 0.40 to 0.65wt% of Mn, 0.060 to 0.100wt% of P, 0.030 to 0.050wt% of S, and the balance of Fe and inevitable impurities; the molten iron, scrap steel and pig iron are respectively 930-940 kg/tSteel、100～115kg/tSteel、30～40kg/tSteelThe amount of (A) is added to the converter.
The bottom of the ladle before tapping in the step A is 2.0kg/tSteelAdding lime in an amount of 1.0kg/tSteelAdding refining slag for slag washing, and adopting a flow of 30-50 NL/min for whole-process bottom argon blowing process during tapping.
In the step B, the silicon-calcium-barium content is 2.0kg/tSteel6.75-7.92 kg/t ferrosiliconSteel18.25-19.20 kg/t of high-carbon ferromanganeseSteel4.25-4.85 kg/t of high-carbon ferrochromeSteelThe ferronickel is added according to the proportion of 3.40-4.45 kg/tSteel1.34-1.51 kg/t of vanadium-nitrogen alloySteelAnd adding a steel ladle.
The silicon-calcium-barium alloy comprises the following components: 52.5wt% of Si, 11.5wt% of Ca, 13.5wt% of Ba, 4.2wt% of Al, and the balance of Fe and inevitable impurities; the ferrosilicon comprises the following components: 73.2wt% of Si, and the balance of Fe and inevitable impurities; the high-carbon ferromanganese comprises the following components: 75.8wt% of Mn, 7.8wt% of C and the balance of Fe and inevitable impurities; the high carbon ferrochrome comprises the following components: 54.2wt% of Cr, 7.8wt% of C, 0.085wt% of P, 0.035wt% of S and the balance of Fe and inevitable impurities; the ferronickel comprises the following components: FeNi20, wherein the Ni accounts for 20 percent, and the balance is Fe and inevitable impurities; the vanadium-nitrogen alloy comprises the following components: 77.6wt% of V, 16.5wt% of N, 3.2wt% of C, and the balance Fe and inevitable impurities.
In the step C, the molten steel is lifted to an LF furnace, argon is blown for 2min at the flow rate of 20-30 NL/min, then slag melting is carried out on a lower electrode at the speed of 6-8 grades, the alkalinity of slag is controlled to be 5.0-7.0, then the temperature of the molten steel is heated to 1540-1550 ℃, and the feeding components are as follows at the feeding linear speed of 2.5 m/s: 56.5wt% of Si, 29.5 wt% of Ca and the balance of Fe and inevitable impurities, wherein 100m of the calcium silicate wire is used for feeding molten steel, soft argon blowing is carried out on the molten steel for more than or equal to 5min at the flow rate of 15-25 NL/min after wire feeding is finished, and then a molten steel covering agent is added according to the amount of 1.0kg/t to finish refining.
In the step D, the secondary cooling specific water amount is 1.5-1.7L/kg, the current intensity of electromagnetic stirring of the crystallizer is 400A, and the operating frequency is 3.0HZUnder the condition of (1), a R12m straight-arc continuous straightening 7-flow bloom casting machine is adopted to cast the molten steel into small billets with the cross sections of 165mm multiplied by 165 mm.
In the step E, the steel billet is fed into a heat-resisting slide rail push type double heat storage heating furnace with the inlet end and the outlet side at the hot charging temperature of 600-650 ℃ for heating, wherein the preheating temperature of blast furnace gas and air is more than or equal to 1000 ℃, the hearth of the heating furnace is operated at a slight positive pressure of 10-15 Pa, and the atmosphere in the furnace is a reducing atmosphere; the temperature of the soaking section of the heating furnace is controlled to be 1080-1120 ℃, the heating time is 70-90 min, and the temperature of the steel billet is controlled to be 990-1020 ℃.
And the step F is to send the heated steel billet to a full continuous rolling bar machine set, and the final rolling steel bar is controlled according to the inner diameter d +/-0.20 mm at the rolling start temperature of 980-1010 ℃, the final rolling temperature of 1000-1020 ℃ and the rolling speed of 6.0-6.2 m/s, and the negative deviation of the weight of the steel bar is controlled to be-1-3%.
And G, shearing the finally rolled steel by a multi-length flying shear, then feeding the steel into a stepping cooling bed for air cooling through a roller way and apron board steel feeding system, aligning, mounting by taking a forming blade with a hole as an upper sheet, performing fixed-length shearing by adopting a downward cutting mode, bundling and stacking for cooling to obtain the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar.
Example 1-Rolling phi 40mm HRB500E Fine-grained high-strength anti-seismic and anti-corrosion reinforcing steel bar
S100: molten iron (chemical components C: 4.0-5.0 wt%, Si: 0.30-0.55 wt%, Mn: 0.30-0.60 wt%, P: 0.080-0.120 wt%, S: 0.045wt%, and the balance Fe and unavoidable impurities), scrap (chemical components C: 0.12-0.20 wt%, Si: 0.15-0.35 wt%, Mn: 0.35-0.65 wt%, P: 0.025-0.040 wt%, S: 0.025-0.040 wt%, and the balance Fe and unavoidable impurities), and pig iron (chemical components C: 3.0-3.5 wt%, Si: 0.30-0.55 wt%, Mn: 0.40-0.65 wt%, P: 0.060-0.100 wt%, S: 0.030-0.050 wt%, and the balance Fe and unavoidable impurities) are added in an amount of 930-940 kg/t%, 930-0.5 wt%, and the balance Fe and unavoidable impurities are addedSteel、100～115kg/tSteel、30～40kg/tSteelAdding the mixture into a 120-ton converter, performing conventional top-bottom combined blowing, adding lime, dolomite and magnesite balls according to a conventional amount for slagging, and controlling the end point carbon content to be 0.08-0.12 wt% and the tapping temperature to be 1620-1660 ℃; lime and refining slag are added to the bottom of the ladle for slag washing before tapping, and the addition amount of the lime is as follows: 2.0kg/tSteelThe adding amount of the refining slag is as follows: 1.0kg/tSteel(ii) a And during tapping, a whole-process bottom argon blowing process is adopted, and the flow rate of argon is controlled to be 30-50 NL/min.
S200: tapping the molten steel smelted in the S100 step, and when the molten steel amount in the ladle is more than 1/4, carrying out the following deoxidation alloying sequence: barium silico-calcium → ferrosilicon → high-carbon ferromanganese → high-carbon ferrochrome → ferronickel (FeNi20) → vanadium-nitrogen alloy, and the following substances are sequentially added to the ladle: at a rate of 2.0kg/tSteelAdding Si-Ca-Ba alloy (chemical components of Si:52.5wt%, Ca:11.5wt%, Ba:13.5wt%, Al:4.2wt%, and the balance of Fe and inevitable impurities); push button6.75～7.92kg/tSteelAdding ferrosilicon (chemical component Si:73.2wt%, the rest is Fe and inevitable impurities); at 18.25-19.20 kg/tSteelHigh-carbon ferromanganese (chemical components of Mn:75.8wt%, C:7.8wt%, and the balance of Fe and inevitable impurities) is added; according to 4.25-4.85 kg/tSteelAdding high-carbon ferrochrome (chemical components of Cr:54.2wt%, C:7.8wt%, P:0.085wt%, S:0.035wt%, and the balance of Fe and inevitable impurities); according to 3.40-4.45 kg/tSteelAdding ferronickel (chemical component FeNi20, wherein Ni is 20%, and the rest is Fe and inevitable impurities); according to the ratio of 1.34-1.51 kg/tSteelThe vanadium-nitrogen alloy (chemical composition V:77.6wt%, N:16.5wt%, C:3.2wt%, and the balance Fe and inevitable impurities) was added in an amount of 3/4, and the addition of the alloy was completed when the amount of molten steel in the ladle reached.
S300: hoisting the molten steel after the S200 steel tapping to an LF furnace refining station to be connected with an argon band, starting argon, blowing argon for 2min by adopting small argon amount (20-30 NL/min), and then melting slag by adopting gears 6-8 on a lower electrode; after electrifying for 3min, lifting an electrode to observe the slagging condition in the furnace: if the slag condition is relatively dilute, adding 4.0-6.0 kg/t limeSteel1.0kg/t calcium carbideSteelRegulating slag, otherwise, adding 1.0-2.0 kg/t of premelted refining slagSteelAdjusting and controlling the slag alkalinity to be 5.5-7.0; then measuring and sampling temperature, adding alloy to adjust the components of the molten steel and heating the lower electrode according to the steel sample and the temperature detection result, and ensuring the components and the temperature to be qualified; then heating the molten steel to 1540-1550 ℃, feeding calcium silicate wire (chemical components of Si:56.5wt%, Ca:29.5 wt%, and the balance of Fe and inevitable impurities), wherein the wire feeding speed is 2.5m/s, and the wire feeding amount is 100 m; carrying out soft argon blowing on the molten steel at the flow rate of 15-25 NL/min for more than or equal to 5min after wire feeding, and then carrying out soft argon blowing on the molten steel at the flow rate of 1.0kg/tSteelAdding the molten steel covering agent in the amount to obtain molten steel with the following components:
0.22 wt% of C, 0.50 wt% of Si, 1.35wt% of Mn, 0.035wt% of S, 0.025wt% of P, 0.235wt% of Cr, 0.085wt% of Ni, 0.105wt% of V, and the balance of Fe and inevitable impurities.
S400: and (3) casting the molten steel into a small square billet with the section of 165mm multiplied by 165mm by adopting an R12m straight-arc 7-flow large square billet casting machine under the conditions that the temperature of the tundish obtained in the step (300) is 1535-1545 ℃, the drawing speed is 2.3-2.5 m/min, the secondary cooling specific water amount is 1.5-1.7L/kg, the electromagnetic stirring current intensity of the crystallizer is 400A, and the operating frequency is 3.0 HZ.
S500: conveying the bloom of S400 to a heat-resisting slide rail push steel type double heat accumulation heating furnace with the end inlet side out for heating through a conveying roller way at the hot charging temperature of 600-650 ℃, wherein the preheating temperature of blast furnace gas and air is more than or equal to 1000 ℃, the hearth of the heating furnace is operated by micro positive pressure of 10-15 Pa, and the atmosphere in the furnace is reducing atmosphere; the temperature of the soaking section of the heating furnace is controlled at 1080 ℃, the heating time is 70-80 min, and the temperature of the billet is controlled at 990-1000 ℃.
S600: conveying the heated steel billets to a full continuous rolling bar machine set through a roller way, and adopting flat/vertical (H/V) alternative typical arrangement through 18 full continuous rolling bar machine sets at the rolling temperature of 980-1000 ℃, wherein the process arrangement is as follows: rough rolling phi 550 × 4/phi 450 × 2, medium rolling phi 450 × 6, finish rolling phi 380 × 6; the rolling speed is V =6.0m/s, and the finish rolling temperature after finish rolling is controlled to be 1000-1010 ℃; the sizes of the material types are strictly controlled in the rolling process, the inner diameter of the finished steel bar is controlled according to d +/-0.20 mm, and the negative deviation of the weight of the steel bar is controlled according to minus 1% -minus 2%.
S700: after being sheared by a double-length flying shear, the rolled steel bar enters a stepping type cooling bed (the area of the cooling bed is 120m multiplied by 9.5 m) through a roller bed and apron plate steel feeding system for air cooling (natural cooling), then the air-cooled steel bar is conveyed to a roller bed before shearing through an alignment roller bed and a steel moving trolley, a forming blade with holes is used as an upper piece for installation, a 850t cold shearing machine is adopted for cutting in a following cutting mode for cutting to length, and the length deviation of the steel bar is controlled according to 0+40 mm; sampling, inspecting and collecting the steel bars subjected to fixed-length shearing and finishing, counting, performing fixed-length bundling (2 at two ends and 2 at the middle at equal intervals), and finally weighing, marking, warehousing, stacking in a shape like a Chinese character jing and naturally cooling to obtain the phi-40 mm HRB500E fine-grain high-strength anti-seismic and anti-corrosion steel bars.
The physical examination of the steel bar obtained above showed the results in table 2.
TABLE 2 physical properties of 40mm phi HRB500E fine-grained high-strength aseismic corrosion-resistant steel bar
Example 2 Rolling of phi 40mm HRB500E Fine-grained high-strength anti-seismic and anti-corrosion reinforcing steel bar
S100: the same as in example 1.
S200: the same as in example 1.
S300: in the same manner as in example 1, a molten steel having the following composition was obtained:
0.23 wt% of C, 0.55wt% of Si, 1.38wt% of Mn, 0.030wt% of S, 0.020wt% of P, 0.238wt% of Cr, 0.090wt% of Ni, 0.107wt% of V, and the balance of Fe and inevitable impurities;
s400: the same as in example 1.
S500: conveying the bloom of S400 to a heat-resisting slide rail push steel type double heat accumulation heating furnace with the end inlet side out for heating through a conveying roller way at the hot charging temperature of 600-650 ℃, wherein the preheating temperature of blast furnace gas and air is more than or equal to 1000 ℃, the hearth of the heating furnace is operated by micro positive pressure of 10-15 Pa, and the atmosphere in the furnace is reducing atmosphere; the temperature of the soaking section of the heating furnace is controlled at 1110 ℃, the heating time is 70-90 min, and the temperature of the steel billet is controlled at 1010-1020 ℃.
S600: conveying the heated steel billets to a full continuous rolling bar machine set through a roller way, and adopting flat/vertical (H/V) alternative typical arrangement through 18 full continuous rolling bar machine sets at the initial rolling temperature of 1000-1005 ℃, wherein the process arrangement is as follows: rough rolling phi 550 × 4/phi 450 × 2, medium rolling phi 450 × 6, finish rolling phi 380 × 6; the rolling speed is V =6.1m/s, and the finish rolling temperature after finish rolling is controlled at 1010 ℃; the sizes of the material types are strictly controlled in the rolling process, the inner diameter of the finished steel bar is controlled according to d +/-0.20 mm, and the negative deviation of the weight of the steel bar is controlled according to minus 1% -minus 3%.
S700: the same as example 1, HRB500E fine crystal high-strength anti-seismic rust-proof steel bar with phi of 40mm is obtained.
The physical examination of the steel bar obtained above showed the results in table 3.
TABLE 3 physical properties of 40mm phi HRB500E fine-grained high-strength aseismic corrosion-resistant steel bar
Example 3 Rolling of phi 40mm HRB500E Fine-grained high-strength anti-seismic and anti-corrosion reinforcing steel bars
S100: the same as in example 1.
S200: the same as in example 1.
S300: in the same manner as in example 1, a molten steel having the following composition was obtained:
0.24 wt% of C, 0.49 wt% of Si, 1.40wt% of Mn, 0.035wt% of S, 0.025wt% of P, 0.245wt% of Cr, 0.100wt% of Ni, 0.112wt% of V, and the balance of Fe and inevitable impurities;
s400: the same as in example 1.
S500: conveying the bloom of S400 to a heat-resisting slide rail push steel type double heat accumulation heating furnace with the end inlet side out for heating through a conveying roller way at the hot charging temperature of 600-650 ℃, wherein the preheating temperature of blast furnace gas and air is more than or equal to 1000 ℃, the hearth of the heating furnace is operated by micro positive pressure of 10-15 Pa, and the atmosphere in the furnace is reducing atmosphere; the temperature of the soaking section of the heating furnace is controlled to be 1110-1120 ℃, the heating time is 80-90 min, and the temperature of the steel billet is controlled to be 1010-1020 ℃.
S600: conveying the heated steel billets to a full continuous rolling bar machine set through a roller way, and adopting flat/vertical (H/V) alternative typical arrangement through 18 full continuous rolling bar machine sets at the initial rolling temperature of 1010 ℃, wherein the process arrangement is as follows: rough rolling phi 550 × 4/phi 450 × 2, medium rolling phi 450 × 6, finish rolling phi 380 × 6; the rolling speed is V = 6.1-6.2 m/s, and the finish rolling temperature after finish rolling is controlled at 1020 ℃; the sizes of the material types are strictly controlled in the rolling process, the inner diameter of the finished steel bar is controlled according to d +/-0.20 mm, and the negative deviation of the weight of the steel bar is controlled according to minus 1% -minus 3%.
S700: the same as example 1, HRB500E fine crystal high-strength anti-seismic rust-proof steel bar with phi of 40mm is obtained.
The physical examination of the steel bar obtained above showed the results in table 4.
TABLE 4 physical properties of 40mm phi HRB500E fine-grained high-strength aseismic corrosion-resistant steel bar
Claims (10)
1. A production method of HRB500E fine-grain high-strength anti-seismic anti-corrosion reinforcing steel bars is characterized by comprising the working procedures of converter smelting, deoxidation alloying, LF furnace refining, square billet continuous casting, billet heating, rolling and cooling, and the specific working procedures comprise:
A. smelting in a converter: adding molten iron, scrap steel and pig iron into a converter to carry out top-bottom combined blowing, adding lime, dolomite and magnesite balls according to a conventional amount for slagging, and controlling the end point carbon content to be 0.08-0.12 wt% and the tapping temperature to be 1620-1660 ℃; lime and refining slag are added to the bottom of the ladle for slag washing before tapping, and a whole-process bottom argon blowing process is adopted during tapping;
B. and (3) deoxidation alloying: tapping the molten steel smelted in the step A, and when the molten steel amount in the steel ladle is more than 1/4, sequentially adding silicon-calcium-barium, silicon-iron, high-carbon ferromanganese, high-carbon ferrochrome, ferronickel and vanadium-nitrogen alloy into the steel ladle until the molten steel amount in the steel ladle reaches 3/4;
C. refining in an LF furnace: and (3) hoisting the molten steel after the step B to an LF furnace, blowing argon by adopting a small argon amount, then melting slag by a lower electrode, controlling the slag alkalinity to be 5.0-7.0, then heating the molten steel to 1540-1550 ℃, feeding a calcium silicate wire, performing soft argon blowing on the molten steel by adopting a small argon amount after the wire feeding is finished, and then adding a molten steel covering agent to finish refining to obtain the molten steel with the following components:
0.21 to 0.24 wt% of C, 0.48 to 0.54 wt% of Si, 1.34 to 1.40wt% of Mn, less than or equal to 0.035wt% of S, less than or equal to 0.025wt% of P, 0.230 to 0.245wt% of Cr, 0.080 to 0.100wt% of Ni, 0.100 to 0.112wt% of V, and the balance of Fe and inevitable impurities;
D. and (3) square billet continuous casting: casting the molten steel into a steel billet by the tundish obtained in the step C under the conditions that the temperature is 1535-1545 ℃, the pulling speed is 2.3-2.5 m/min and the crystallizer is electromagnetically stirred;
E. heating a steel billet: heating the billet obtained in the step D to 990-1020 ℃ in a hearth of a micro-positive pressure heating furnace at a hot charging temperature of 600-650 ℃;
F. rolling: and E, rolling the billet heated in the step E at a start rolling temperature of 980-1010 ℃ and a finish rolling temperature of 1000-1020 ℃ by adopting a flat/cross alternative rolling method:
G. and (3) cooling: and F, air cooling the steel after the finish rolling in the step F, then cutting the steel to length, bundling and stacking the steel for cooling to obtain the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar.
2. The production method of the HRB500E fine-grained high-strength anti-seismic anti-rust steel bar as claimed in claim 1, wherein the molten iron in the step A comprises the following components: 4.0-5.0 wt% of C, 0.30-0.55 wt% of Si, 0.30-0.60 wt% of Mn, 0.080-0.120 wt% of P, less than or equal to 0.045wt% of S, and the balance of Fe and inevitable impurities; the steel scrap comprises the following components: 0.12 to 0.20wt% of C, 0.15 to 0.35 wt% of Si, 0.35 to 0.65wt% of Mn, 0.025 to 0.040wt% of P, 0.025 to 0.040wt% of S, and the balance of Fe and inevitable impurities; the pig iron comprises the following components: 3.0 to 3.5wt% of C, 0.30 to 0.55wt% of Si, 0.40 to 0.65wt% of Mn, 0.060 to 0.100wt% of P, 0.030 to 0.050wt% of S, and the balance of Fe and inevitable impurities; the molten iron, scrap steel and pig iron are respectively 930-940 kg/tSteel、100～115kg/tSteel、30～40kg/tSteelThe amount of (A) is added to the converter.
3. The method for producing the HRB500E fine-grained high-strength anti-seismic and anti-rust reinforcing steel bar as claimed in claim 2, wherein the bottom of the ladle is at a ratio of 2.0kg/t before tapping in the step ASteelAdding lime in an amount of 1.0kg/tSteelAdding refining slag for slag washing, and adopting a flow of 30-50 NL/min for whole-process bottom argon blowing process during tapping.
4. The method for producing the HRB500E fine-grained high-strength anti-seismic anti-rust reinforcing steel bar according to claim 1, 2 or 3, wherein the Si-Ca-Ba content in the step B is 2.0kg/tSteel6.75-7.92 kg/t ferrosiliconSteel18.25-19.20 kg/t of high-carbon ferromanganeseSteel4.25-4.85 kg/t of high-carbon ferrochromeSteelThe ferronickel is added according to the proportion of 3.40-4.45 kg/tSteel1.34-1.51 kg/t of vanadium-nitrogen alloySteelAnd adding a steel ladle.
5. The method for producing the HRB500E fine-grained high-strength anti-seismic anti-rust reinforcing steel bar according to claim 4, wherein the silicon, calcium and barium comprise the following components: 52.5wt% of Si, 11.5wt% of Ca, 13.5wt% of Ba, 4.2wt% of Al, and the balance of Fe and inevitable impurities; the ferrosilicon comprises the following components: 73.2wt% of Si, and the balance of Fe and inevitable impurities; the high-carbon ferromanganese comprises the following components: 75.8wt% of Mn, 7.8wt% of C and the balance of Fe and inevitable impurities; the high carbon ferrochrome comprises the following components: 54.2wt% of Cr, 7.8wt% of C, 0.085wt% of P, 0.035wt% of S and the balance of Fe and inevitable impurities; the ferronickel comprises the following components: FeNi20, wherein the Ni accounts for 20 percent, and the balance is Fe and inevitable impurities; the vanadium-nitrogen alloy comprises the following components: 77.6wt% of V, 16.5wt% of N, 3.2wt% of C, and the balance Fe and inevitable impurities.
6. The production method of the HRB500E fine-grain high-strength anti-seismic anti-corrosion reinforcing steel bar according to claim 4, wherein in the step C, the molten steel is hoisted to an LF furnace, argon is blown for 2min at a flow rate of 20-30 NL/min, then slag melting is performed on a lower electrode at a speed of 6-8 grades, the alkalinity of the slag is controlled to be 5.0-7.0, then the temperature of the molten steel is heated to 1540-1550 ℃, and the feeding components are as follows at a feeding speed of 2.5 m/s: 56.5wt% of Si, 29.5 wt% of Ca and the balance of Fe and inevitable impurities, wherein 100m of the calcium silicate wire is used for feeding molten steel, soft argon blowing is carried out on the molten steel for more than or equal to 5min at the flow rate of 15-25 NL/min after wire feeding is finished, and then a molten steel covering agent is added according to the amount of 1.0kg/t to finish refining.
7. The production method of the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar according to claim 6, wherein the secondary cooling water ratio in the step D is 1.5-1.7L/kg, the electromagnetic stirring current intensity of the crystallizer is 400A, and the operating frequency is 3.0HZUnder the condition of (1), a R12m straight-arc continuous straightening 7-flow bloom casting machine is adopted to cast the molten steel into small billets with the cross sections of 165mm multiplied by 165 mm.
8. The production method of the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar according to claim 7, wherein the step E is to feed the steel billet into a heat-resistant slide rail push type double heat storage heating furnace for heating at a hot charging temperature of 600-650 ℃, wherein the preheating temperature of blast furnace gas and air is more than or equal to 1000 ℃, the furnace hearth of the heating furnace is operated at a slight positive pressure of 10-15 Pa, and the atmosphere in the furnace is a reducing atmosphere; the temperature of the soaking section of the heating furnace is controlled to be 1080-1120 ℃, the heating time is 70-90 min, and the temperature of the steel billet is controlled to be 990-1020 ℃.
9. The method for producing the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar according to claim 8, wherein the step F is to send the heated steel billet to a full continuous rolling bar machine set, the inner diameter of the finally rolled steel bar is controlled within d +/-0.20 mm according to the start rolling temperature of 980-1010 ℃, the finish rolling temperature of 1000-1020 ℃ and the rolling speed of 6.0-6.2 m/s, and the negative deviation of the weight of the steel bar is controlled within-1-3%.
10. The method for producing the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar according to claim 9, wherein the step G comprises shearing the finally rolled steel by a double-length flying shear, feeding the steel into a stepping cooling bed through a roller table and apron plate steel feeding system for air cooling, aligning, installing a strip-hole forming blade as an upper piece, shearing the steel to a fixed length by a downward cutting method, bundling and stacking for cooling to obtain the HRB500E fine-grain high-strength anti-seismic anti-rust steel bar.
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| CN115181904A (en) * | 2021-11-05 | 2022-10-14 | 柳州钢铁股份有限公司 | High-safety hot-rolled steel bar |
| CN115386788B (en) * | 2022-09-05 | 2024-04-30 | 阳春新钢铁有限责任公司 | Cold bending cracking control process for HRB500E deformed steel bar |
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| CN115386788B (en) * | 2022-09-05 | 2024-04-30 | 阳春新钢铁有限责任公司 | Cold bending cracking control process for HRB500E deformed steel bar |
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