CN111235350B - Strengthening method for adding vanadium-titanium balls in construction steel bar smelting process - Google Patents
Strengthening method for adding vanadium-titanium balls in construction steel bar smelting process Download PDFInfo
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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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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
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- 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
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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
- 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
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Abstract
The invention discloses a strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process, which comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added in the steel tapping deoxidation alloying of a molten steel converter, the molten steel is hoisted to an LF refining furnace to be supplemented with the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon in the molten steel and the temperature of refining reducing atmosphere are controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved. The vanadium-titanium ball is creatively added in the process of smelting the building reinforcing steel bar, and beneficial strengthening alloy elements V, Ti and Cr with higher content in the vanadium-titanium ball are reduced into the molten steel through the control of molten steel carbon, temperature and reduction reaction atmosphere, so that a composite strengthening effect is achieved; the process is simple to operate, the reduction yield is stable, and the production cost of the construction steel bar is reduced.
Description
Technical Field
The invention belongs to the technical field of smelting, and particularly relates to a strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process.
Background
HRB400 is named as hot-rolled ribbed steel bar, and the diameter is 6-100 mm. HRB400 is a twisted steel bar number specified in national mandatory standard GB 1499.2-2007 Hot rolled ribbed steel bar for reinforced concrete, the implementation is started from 2008, 3, 1, the new standard replaces GB1499-1998 Hot rolled ribbed steel bar for reinforced concrete and GB13014-1991 waste heat treatment steel bar for reinforced concrete, and compared with the original standard GB1499-1998, grade III steel bar in the old standard is called HRB400 steel bar under the new standard. Due to the wide range of standard components and the difference of production equipment and process control of manufacturers, the components of HRB400 hot-rolled ribbed steel bars produced by the manufacturers are different, and the production processes of steel mills are different.
HRB500 is a hot-rolled ribbed IV-grade steel bar specified in the national standard GB1499.2-2018 Hot-rolled ribbed steel bar for reinforced concrete, is called a four-grade steel bar, has the yield strength of not less than 500Mpa and the diameter of generally 6-100 mm. The national mandatory standard GB1499.2-2018 hot-rolled ribbed steel bars for reinforced concrete is implemented from 11 months and 1 day in 2018, the new standard replaces GB1499-2007 hot-rolled ribbed steel bars for reinforced concrete and GB13014-1991 waste heat treatment steel bars for reinforced concrete, and compared with the original standard GB1499-2007, the IV-grade steel bars in the old standard are changed into HRB 500-grade steel bars under the new standard.
HRB400 and HRB500 building material steel bars are important components in building steel in China and are widely applied to infrastructure and civil engineering in China. The implementation of the new national standard GB/T1499.2-2018 is a huge shock for steel bar production enterprises. The new national standard correspondingly standardizes the metallographic structure, the strength grade and the weight deviation of the steel bar. The specification prompts various production enterprises to research a reasonable reinforcing steel bar reinforcing mode, meets the new requirements of the construction industry on the reinforcing steel bar development, and promotes the new trends of innovative development and high-quality development of steel enterprises. Under such a situation, alloy strengthening is a common research direction for various production enterprises.
Currently, there are some publications on HRB400 construction rebar or HRB500 construction rebar, such as:
1. patent application No. cn201811016844.x discloses an HRB400 steel bar and a production method of the HRB400 steel bar, wherein the HRB400 steel bar comprises the following chemical components in percentage by mass: 0.19-0.25% of C, 0.55-0.80% of Si, 1.45-1.60% of Mn, 0.02-0.04% of V, 0.008-0.010% of N, and the balance of Fe and inevitable impurities. According to the technical scheme, the strength is improved by utilizing vanadium-nitrogen microalloying, and compared with the method adopting ferrovanadium microalloying, the cost is reduced, so that the HRB400 steel bar has the advantages of excellent and stable mechanical property and low cost.
2. Patent application CN201510286456.3 discloses an HRB400 earthquake-resistant corrosion-resistant steel bar, which is composed of the following components by weight: c: 0.01 to 0.10 percent; si: 0.10-0.30%; mn: 0.20-0.80%; ni: 0.01 to 0.05 percent; cr: 0.01 to 0.05 percent; nb: 0.02-0.03%; p: 0.02% -0.03%; s: less than or equal to 0.03 percent; mo is less than or equal to 0.02 percent; the invention utilizes the cheap laterite-nickel ore resources to replace part of iron ore resources to smelt steel, so that a large amount of iron in the laterite-nickel ore is effectively utilized, and the addition of nickel, chromium, titanium and other components in the laterite-nickel ore replaces part of conventional manganese, vanadium and niobium elements to refine crystal grains of steel, thereby improving the seismic performance and the corrosion resistance of the steel.
3. Patent application CN201710139657.X discloses a 500MPa anti-seismic steel bar and a production process, wherein the steel bar contains calcium-based composite particles, and the steel bar comprises the following elements: 10 to 15 percent of Ca, 12 to 13 percent of Si, 2 to 3 percent of Al, 30 to 35 percent of Mn, 4 to 5 percent of S, 30 to 35 percent of O and 100 percent of the sum of the mass percentages of the elements. In the production process, after molten steel is poured into a tundish, calcium carbide is added into a crystallizer for final deoxidation, the amount of the added calcium carbide is controlled so that the oxygen content in the molten steel of the steel bar is reduced to 30-50 ppm, calcium-based composite particles are generated, and the steel bar is cooled at the temperature of 800-500 ℃ at the speed of 5-15 ℃/s. According to the invention, a certain amount of calcium carbide is added into the crystallizer for secondary deoxidation after molten steel tapping, so that a large amount of fine particles such as CaO and the like which are dispersed and distributed in the steel are generated, under the condition of controlling the cooling speed, the calcium-based composite particles are used as heterogeneous nucleation cores to promote the formation of acicular ferrite in the crystal, and original austenite grains are refined, thereby improving the strength and toughness of the steel bar.
4. Patent application CN201410140848.4 discloses an HRB 500-grade hot-rolled ribbed anti-seismic steel bar and a preparation method thereof. The steel comprises the following chemical components in percentage by weight: c: 0.17 to 0.25%, Si: 0.4-0.8%, Mn: 1.2-1.5%, P is less than or equal to 0.045%, S is less than or equal to 0.045%, V: 0.028 ~ 0.045%, N: 0.008 to 0.014 percent, and the balance of Fe and inevitable impurity elements. The preparation method comprises the steps of molten iron desulphurization, converter smelting, argon blowing, continuous casting, square billet heating, rolling, controlled cooling after rolling and cooling by a cooling bed. The steel has the advantages of high strength, high toughness and low manufacturing cost, and the preparation process is simple and the production cost is low.
However, the mechanical strength of the existing HRB400 and HRB500 construction steel bars is not good, the yield is unstable, and in order to improve the strength of the steel bars, the prior art also adopts methods of rapidly cooling and strengthening fine grains to improve the strength of the steel bars, or improves the strength of the steel bars by microalloying, but the cost is higher.
Disclosure of Invention
The invention provides a strengthening method for adding vanadium-titanium balls in the process of smelting construction steel bars, which aims to solve the technical problems. The method combines the research results of using vanadium-titanium balls for many years, creatively adds the vanadium-titanium balls in the smelting process of the building reinforcing steel bars HRB400 and HRB500, and controls the carbon, temperature and reduction reaction atmosphere of molten steel to promote beneficial strengthening alloy elements V, Ti and Cr with higher content in the vanadium-titanium balls to be reduced into the molten steel, so that the composite strengthening effect is achieved, the strength of the reinforcing steel bars is improved, the reduction yield is stable, the prepared reinforcing steel bars meet the new national standard requirements of the building reinforcing steel bars, the production cost of the building reinforcing steel bars is reduced, and the method is easy to popularize and apply.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added in the steel tapping deoxidation alloying of a molten steel converter, the molten steel is hoisted to an LF refining furnace to be supplemented with the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon in the molten steel and the temperature of refining reducing atmosphere are controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved.
Further, the strengthening method for adding the vanadium-titanium balls in the construction steel bar smelting process comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10 percent, the slag-stopping tapping temperature is controlled to be 1650-1680 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizing agent after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not completely discharged, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 1-3 min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.0-3.5, the FeO% + MnO% in the white slag is less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, discharging and weakly blowing for 4.5-5.5 min to hoist to a continuous casting level;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.06-0.1% of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.5-1.2% of the weight of the molten steel; the adding amount of the aluminum particles is 0.004-0.006% of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0-0.5% of the weight of the molten steel; the adding amount of the vanadium-titanium balls for the third time is 0-0.5% of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.008-0.012% of the weight of the molten steel, and the adding amount of the aluminum particles is 0.02-0.05% of the weight of the molten steel; the adding amount of the lime is 0.55-0.65% of the weight of the molten steel.
Further, in the step (3), the refining temperature is controlled to be 1620 ℃ to 1640 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1525-1550 ℃, and the drawing speed is 2.20-2.60 m/min.
Further, in the step (5), the construction steel bar is hot-rolled ribbed steel bar HRB400 or HRB500, wherein the yield strength of HRB400 is 430 MPa-460 MPa, the tensile strength is 615 MPa-640 MPa, the elongation is 20% -25%, and the yield ratio is 1.30-1.45; the yield strength of HRB500 is 530 MPa-570 MPa, the tensile strength is 720 MPa-760 MPa, the elongation is 15% -25%, and the yield ratio is 1.25-1.45.
Further, the HRB400 comprises the following components in percentage by weight: c: 0.20-0.25%, Si: 0.40-0.60%, Mn: 1.30 to 1.50 percent of the total weight of the alloy, less than or equal to 0.045 percent of P, less than or equal to 0.045 percent of S, and the balance of Fe and inevitable impurities, wherein the content of the impurities is less than or equal to 0.04 percent; the HRB500 comprises the following components in percentage by weight: c: 0.21% -0.25%, Si: 0.60-0.80%, Mn: 1.40 to 1.60 percent of the total weight of the alloy, less than or equal to 0.045 percent of P, less than or equal to 0.045 percent of S, and the balance of Fe and inevitable impurities, wherein the content of the impurities is less than or equal to 0.04 percent.
Further, in the step (5), the rolling specification is one of phi 12mm multiplied by 4 slitting rolling, phi 14 multiplied by 4 slitting rolling, phi 16mm multiplied by 2 slitting rolling, phi 20-phi 22mm multiplied by 2 slitting rolling, phi 25mm and phi 28mm rolling; the initial rolling temperature of the rolling is 1065-1081 ℃, and the final rolling temperature is 930-950 ℃.
Further, the vanadium-titanium ball comprises the following components in percentage by weight: s: 0.010% -0.015% of SiO2：4.50％～5.50％，FeO：3.50％～5.00％，MgO：2.50％～3.50％，MnO：0.15％～0.25％，P：0.001％～0.015％，Cu：0.016％～0.040％，TiO2：10.0％～15.0％，Cr：0.35％～2.20％，V2O5: 0.80 to 1.50 percent, and the balance of Fe and inevitable impurities, wherein the content of the impurities is less than or equal to 0.04 percent.
Due to the adoption of the technical scheme, the invention has the following beneficial effects:
(1) the method combines the use research results of the vanadium-titanium balls for many years, creatively adds the vanadium-titanium balls in the smelting process of the building reinforcing steel bars HRB400 and HRB500, and promotes beneficial strengthening alloy elements V, Ti and Cr with higher content in the vanadium-titanium balls to be reduced into molten steel through controlling molten steel carbon, temperature and reduction reaction atmosphere, thereby playing a role in composite strengthening.
(2) The process has the advantages of simple operation, stable reduction yield and low cost far lower than the cost of reinforcing by adopting VFe, TiFe and CrFe under the conventional process, the prepared reinforcing steel bar meets the new national standard requirement of the construction reinforcing steel bar, the production cost of the construction reinforcing steel bar is reduced, and the process is easy to popularize and apply.
Detailed Description
The following is a detailed description of the embodiments of the present invention, but the present invention is not limited to these embodiments, and any modifications or substitutions in the basic spirit of the embodiments are included in the scope of the present invention as claimed in the claims.
The components of the vanadium-titanium spheres used in examples 1 to 5 of the present application are shown in table 1 below in terms of weight percentage.
TABLE 1
Example 1
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1650 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 1min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.0, the FeO% and MnO% in the white slag is less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 4.5min to be hoisted to be continuous casting flat;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.06 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.5 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.004 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.1% of the weight of the molten steel; the adding amount of the third vanadium-titanium ball is 0.3 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.008 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.02 percent of the weight of the molten steel; the adding amount of the lime is 0.55 percent of the weight of the molten steel; the refining temperature was controlled to 1620 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1525 ℃, and the drawing speed is 2.20 m/min.
Further, in step (5), the construction steel bar is a hot-rolled ribbed steel bar HRB400, wherein the yield strength of HRB400 is 453MPa, the tensile strength is 626MPa, the elongation is 23.2%, and the yield ratio is 1.38; the rolling specification is phi 12mm multiplied by 4 slitting rolling; the initial rolling temperature of the rolling is 1078 ℃, and the final rolling temperature is 940 ℃.
Example 2
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1680 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 3min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.5, the FeO% and the MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 5.5min to be hoisted to be flat for continuous casting;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.1 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.6 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.006 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.3% of the weight of the molten steel; the adding amount of the third vanadium-titanium ball is 0.2 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.012 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.05 percent of the weight of the molten steel; the adding amount of the lime is 0.65 percent of the weight of the molten steel; the refining temperature is controlled to be 1640 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1550 ℃, and the drawing speed is 2.60 m/min.
Further, in step (5), the construction steel bar is a hot-rolled ribbed steel bar HRB400, wherein the yield strength of the HRB400 is 442MPa, the tensile strength is 622MPa, the elongation is 24.6%, and the yield ratio is 1.41; the rolling specification phi 16mm multiplied by 2 is cut and rolled; the initial rolling temperature of the rolling is 1070 ℃, and the final rolling temperature is 948 ℃.
Example 3
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting the molten steel in a converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1655 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 1.3min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.2, the FeO% and MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking out of the station and blowing for 4.7min to hoist to the continuous casting level;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.07 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.5 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.004 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.3% of the weight of the molten steel; the adding amount of the third vanadium-titanium ball is 0.3 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.009% of the weight of the molten steel, and the adding amount of the aluminum particles is 0.03% of the weight of the molten steel; the adding amount of the lime is 0.56 percent of the weight of the molten steel; the refining temperature was controlled at 1625 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1530 ℃, and the casting speed is 2.25 m/min.
Further, in step (5), the construction steel bar is a hot-rolled ribbed steel bar HRB400, wherein the yield strength of the HRB400 is 460MPa, the tensile strength is 632MPa, the elongation is 24.3%, and the yield ratio is 1.37; the rolling specification phi 22mm multiplied by 2 is cut and rolled; the initial rolling temperature of the rolling is 1075 ℃, and the final rolling temperature is 950 ℃.
Example 4
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1675 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing of the argon at the bottom to weak blowing for 2.9min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.4, the FeO% and MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 5.4min to be hoisted to be flat for continuous casting;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.09 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.6 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.006 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.3% of the weight of the molten steel; the adding amount of the third vanadium-titanium ball is 0.2 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.011 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.047 percent of the weight of the molten steel; the adding amount of the lime is 0.63 percent of the weight of the molten steel; the refining temperature was controlled at 1637 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1548 ℃, and the casting speed is 2.57 m/min.
Further, in step (5), the construction steel bar is hot-rolled ribbed steel bar HRB400, wherein the yield strength of HRB400 is 450MPa, the tensile strength is 619MPa, the elongation is 24.3%, and the yield ratio is 1.38; the rolling specification is phi 25 mm; the initial rolling temperature of the rolling is 1080 ℃ and the final rolling temperature is 948 ℃.
Example 5
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1665 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 2min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.3, the FeO% and the MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 5.0min to be hoisted to the continuous casting level;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.08 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.5 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.005 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.25% of the weight of the molten steel; the adding amount of the vanadium-titanium ball for the third time is 0.4 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.010 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.035 percent of the weight of the molten steel; the adding amount of the lime is 0.60 percent of the weight of the molten steel; the refining temperature was controlled at 1630 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1540 ℃, and the casting speed is 2.40 m/min.
Further, in step (5), the construction steel bar is hot-rolled ribbed steel bar HRB400, wherein the yield strength of HRB400 is 446MPa, the tensile strength is 624MPa, the elongation is 24.3%, and the yield ratio is 1.40; the rolling specification is phi 28 mm; the initial rolling temperature of the rolling is 1073 ℃, and the final rolling temperature is 940 ℃.
The components and performance test results of HRB400 prepared in examples 1-5 are shown in Table 2 below.
TABLE 2
The components of the vanadium-titanium spheres used in examples 6 to 10 of the present application are, in weight percent, shown in table 3 below.
TABLE 3
Example 6
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1660 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 1min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.2, the FeO% and MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 4.6min to be hoisted to be flat for continuous casting;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.06 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.7 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.004 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.4% of the weight of the molten steel; the adding amount of the third vanadium-titanium ball is 0.3 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.008 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.02 percent of the weight of the molten steel; the adding amount of the lime is 0.55 percent of the weight of the molten steel; the refining temperature was controlled to 1620 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1530 ℃, and the casting speed is 2.30 m/min.
Further, in step (5), the construction steel bar is hot-rolled ribbed steel bar HRB500, the yield strength of HRB500 is 554MPa, the tensile strength is 725MPa, the elongation is 23.5%, and the yield ratio is 1.31; the rolling specification is phi 12mm multiplied by 4 slitting rolling; the initial rolling temperature of the rolling is 1081 ℃, and the final rolling temperature is 950 ℃.
Example 7
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1670 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 3min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.1, the FeO% and MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 5.5min to be hoisted to be flat for continuous casting;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.1 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.8 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.006 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.3% of the weight of the molten steel; the adding amount of the third vanadium-titanium ball is 0.3 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.012 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.05 percent of the weight of the molten steel; the adding amount of the lime is 0.63 percent of the weight of the molten steel; the refining temperature is controlled to be 1640 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1545 ℃, and the casting speed is 2.50 m/min.
Further, in the step (5), the construction steel bar is hot-rolled ribbed steel bar HRB500, the yield strength of HRB500 is 562MPa, the tensile strength is 728MPa, the elongation is 24.6%, and the yield ratio is 1.30; the rolling specification is phi 14 multiplied by 4 slitting rolling; the initial rolling temperature of the rolling is 1080 ℃, and the final rolling temperature is 944 ℃.
Example 8
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1660 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 1.5min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3..2, the FeO% + MnO% in the white slag is less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking out of the station and blowing for 4.8min to hoist to the continuous casting level;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.07 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.8 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.004-0.006% of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.5% of the weight of the molten steel; the adding amount of the vanadium-titanium ball for the third time is 0.35 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.009% of the weight of the molten steel, and the adding amount of the aluminum particles is 0.03% of the weight of the molten steel; the adding amount of the lime is 0.58 percent of the weight of the molten steel; the refining temperature was controlled at 1625 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1535 ℃, and the drawing speed is 2.30 m/min.
Further, in step (5), the construction steel bar is hot-rolled ribbed steel bar HRB500, the yield strength of HRB500 is 540MPa, the tensile strength is 730MPa, the elongation is 22%, and the yield ratio is 1.35; the rolling specification is phi 20mm multiplied by 2 slitting rolling; the initial rolling temperature of the rolling is 1070 ℃, and the final rolling temperature is 940 ℃.
Example 9
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1670 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing of the argon at the bottom to weak blowing for 2.5min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.4, the FeO% and MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 5.3min to be hoisted to be flat for continuous casting;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.09 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.9 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.006 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.4% of the weight of the molten steel; the adding amount of the vanadium-titanium ball for the third time is 0.35 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.011 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.045 percent of the weight of the molten steel; the adding amount of the lime is 0.62 percent of the weight of the molten steel; the refining temperature was controlled at 1635 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1540 ℃, and the casting speed is 2.50 m/min.
Further, in step (5), the construction steel bar is hot-rolled ribbed steel bar HRB500, and the yield strength of HRB500 is 550MPa, the tensile strength is 750MPa, the elongation is 24%, and the yield ratio is 1.40; the rolling specification is phi 25 mm; the initial rolling temperature of the rolling is 1065 ℃, and the final rolling temperature is 947 ℃.
Example 10
A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process comprises the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added through steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon and refining reducing atmosphere in the molten steel is controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved, and the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10%, the slag-stopping tapping temperature is controlled at 1668 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizer after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not discharged completely, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 2min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.3, the FeO% and the MnO% in the white slag are less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, taking the molten steel out of a station and weakly blowing the molten steel for 5.0min to be hoisted to the continuous casting level;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: and rolling the molten steel after the continuous casting to obtain the construction steel bar.
Further, in the step (2), the addition amount of the deoxidizer is 0.08 percent of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.9 percent of the weight of the molten steel; the adding amount of the aluminum particles is 0.005 percent of the weight of the molten steel.
Further, in the step (3), the adding amount of the second vanadium-titanium ball is 0.3% of the weight of the molten steel; the adding amount of the vanadium-titanium ball for the third time is 0.4 percent of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.010 percent of the weight of the molten steel, and the adding amount of the aluminum particles is 0.035 percent of the weight of the molten steel; the adding amount of the lime is 0.60 percent of the weight of the molten steel; the refining temperature was controlled at 1630 ℃.
Further, in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1540 ℃, and the casting speed is 2.40 m/min.
Further, in step (5), the construction steel bar is hot-rolled ribbed steel bar HRB500, and the yield strength of HRB500 is 545MPa, the tensile strength is 734MPa, the elongation is 23.8%, and the yield ratio is 1.35; the rolling specification is phi 28 mm; the initial rolling temperature of the rolling is 1075 ℃, and the final rolling temperature is 933 ℃.
The HRB500 components and performance test results obtained in examples 6-10 are shown in Table 4 below.
TABLE 4
To further illustrate that the present invention can achieve the technical effects, the following experiments were performed:
the HRB400 is prepared by adopting a traditional process, which comprises the following specific steps: the vanadium-nitrogen alloy is directly added during converter alloying, LF refining treatment is not carried out, and the Si content is about 0.70 percent which is 0.20 percent higher than that of the invention; the content of V is 0.020%, which is about 0.005% higher than that of the invention; no Ti is added; the rolling process comprises the following steps: the initial rolling temperature is 1030-1050 ℃, and the final rolling temperature is 850-900 ℃.5 parallel experiments were performed simultaneously and labeled comparative example 1, comparative example 2, comparative example 3, comparative example 4, and comparative example 5, and the results of comparison of the HRB400 components prepared in each comparative example with performance tests are shown in Table 5 below.
TABLE 5
By comparing examples 1-5 with comparative examples 1-5, the invention directly uses vanadium-titanium balls to reduce and obtain strong alloy elements such as V, Ti, Cr and the like, reduces the use amount of VFe alloy and SiFe alloy, and has relatively low production cost.
In addition, the HRB500 is prepared by adopting a traditional process, and the specific process comprises the following steps: vanadium-nitrogen alloy and VFe alloy are added during converter alloying, LF refining fine adjustment component treatment is carried out, and the content of Si is about 0.65 percent, which is 0.05 percent lower than that of the invention; the content of V is 0.085 percent, which is about 0.065 percent higher than that of the invention; no strengthening Ti element; the rolling process comprises the following steps: the initial rolling temperature is 1050-1080 ℃, and the final rolling temperature is 850-900 ℃.5 parallel experiments were performed simultaneously and labeled comparative example 6, comparative example 7, comparative example 8, comparative example 9, and comparative example 10, and the results of comparison of the HRB500 components prepared in each comparative example with performance tests are shown in Table 6 below.
TABLE 6
By comparing examples 6-10 with comparative examples 6-10, the invention directly uses vanadium-titanium balls for reduction to obtain the V, Ti, Cr and other strong alloy elements, reduces the use amount of VFe alloy, and realizes lower V, Ti and Cr contents to achieve better strengthening effect. The vanadium-titanium ball is lower in price than VFe, TiFe and CrFe which are independent, so that the production cost is relatively low.
In summary, the application combines the research results of using vanadium-titanium balls for many years, the vanadium-titanium balls are creatively added in the smelting process of the building reinforcing steel bars HRB400 and HRB500, and beneficial strengthening alloy elements V, Ti and Cr with higher content in the vanadium-titanium balls are reduced into molten steel through molten steel carbon, temperature and reduction reaction atmosphere control, so that a composite strengthening effect is achieved; the process is simple to operate, the reduction yield is stable, the cost is far lower than the cost of reinforcing by adopting VFe, TiFe and CrFe under the conventional process, the prepared reinforcing steel bar meets the new national standard requirement of the construction reinforcing steel bar, the production cost of the construction reinforcing steel bar is reduced, and the popularization and the application are easy.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (8)
1. A strengthening method for adding vanadium-titanium balls in a construction steel bar smelting process is characterized by comprising the following steps: in the steel bar smelting process, a part of vanadium-titanium balls are added in the steel tapping deoxidation alloying of a molten steel converter, then the molten steel is hoisted to an LF refining furnace to supplement the vanadium-titanium balls, ferrosilicon powder and aluminum particles are used for deoxidation to produce reducing white slag, argon stirring is adopted in bottom blowing in the whole production process, the temperature of carbon in the molten steel and the temperature of refining reducing atmosphere are controlled, beneficial strengthening alloy elements V, Ti and Cr with high content in the vanadium-titanium balls are promoted to be reduced into the molten steel, and the effect of compositely strengthening the construction steel bars is achieved;
the method specifically comprises the following steps:
(1) tapping by a converter: smelting in a molten steel converter, wherein the tapping carbon is more than or equal to 0.10 percent, the slag-stopping tapping temperature is controlled to be 1650-1680 ℃, and the tapping time is more than or equal to 3 min;
(2) and (3) deoxidation alloying: adding a deoxidizing agent after the molten steel converter for deoxidation alloying, adding a first vanadium-titanium ball before the molten steel is deoxidized and alloyed and the molten steel is not completely discharged, blowing argon at the bottom of a steel ladle for stirring, adjusting the blowing argon at the bottom to weak blowing for 1-3 min after the molten steel is discharged, closing the bottom blowing after the weak blowing is finished, and uniformly scattering aluminum particles on the slag surface;
(3) LF refining and slagging: hoisting the molten steel added with the vanadium-titanium balls to LF to produce reducing slag, heating, supplementing the vanadium-titanium balls in the LF for the second time according to the deoxidation alloying condition, adding lime and the refining slag for slagging at the beginning of refining, deoxidizing by adopting ferrosilicon powder and aluminum particles to produce reducing white slag, wherein the alkalinity of top slag is 3.0-3.5, the FeO% + MnO% in the white slag is less than or equal to 1.5%, adding the vanadium-titanium balls for the third time, and after the temperature of the molten steel meets the requirement, discharging and weakly blowing for 4.5-5.5 min to hoist to a continuous casting level;
(4) continuous casting: continuously casting the molten steel subjected to LF refining and slagging, and performing full-protection pouring;
(5) rolling: rolling the molten steel after the continuous casting to obtain the construction steel bar;
the vanadium-titanium ball comprises the following components in percentage by weight: s: 0.010% -0.015% of SiO2：4.50％～5.50％，FeO：3.50％～5.00％，MgO：2.50％～3.50％，MnO：0.15％～0.25％，P：0.001％～0.015％，Cu：0.016％～0.040％，TiO2：10.0％～15.0％，Cr：0.35％～2.20％，V2O5: 0.80 to 1.50 percent, and the balance of Fe and inevitable impurities, wherein the content of the impurities is less than or equal to 0.04 percent.
2. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars according to claim 1, which is characterized in that: in the step (2), the addition amount of the deoxidizer is 0.06-0.1% of the weight of the molten steel; the adding amount of the first vanadium-titanium ball is 0.5-1.2% of the weight of the molten steel; the adding amount of the aluminum particles is 0.004-0.006% of the weight of the molten steel.
3. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars according to claim 1, which is characterized in that: in the step (3), the adding amount of the second vanadium-titanium ball is 0-0.5% of the weight of the molten steel; the adding amount of the vanadium-titanium balls for the third time is 0-0.5% of the weight of the molten steel; the adding amount of the ferrosilicon powder is 0.008-0.012% of the weight of the molten steel, and the adding amount of the aluminum particles is 0.02-0.05% of the weight of the molten steel; the adding amount of the lime is 0.55-0.65% of the weight of the molten steel.
4. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars according to claim 1, which is characterized in that: in the step (3), the refining temperature is controlled to be 1620-1640 ℃.
5. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars according to claim 1, which is characterized in that: in the step (4), the section of the continuously cast blank is 160mm multiplied by 160mm, the tundish temperature is 1525-1550 ℃, and the drawing speed is 2.20-2.60 m/min.
6. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars according to claim 1, which is characterized in that: in the step (5), the construction steel bar is hot-rolled ribbed steel bar HRB400 or HRB500, wherein the yield strength of HRB400 is 430 MPa-460 MPa, the tensile strength is 615 MPa-640 MPa, the elongation is 20% -25%, and the yield ratio is 1.30-1.45; the yield strength of HRB500 is 530 MPa-570 MPa, the tensile strength is 720 MPa-760 MPa, the elongation is 15% -25%, and the yield ratio is 1.25-1.45.
7. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars, according to claim 6, is characterized in that: the HRB400 comprises the following components in percentage by weight: c: 0.20-0.25%, Si: 0.40-0.60%, Mn: 1.30 to 1.50 percent of the total weight of the alloy, less than or equal to 0.045 percent of P, less than or equal to 0.045 percent of S, and the balance of Fe and inevitable impurities, wherein the content of the impurities is less than or equal to 0.04 percent; the HRB500 comprises the following components in percentage by weight: c: 0.21% -0.25%, Si: 0.60-0.80%, Mn: 1.40 to 1.60 percent of the total weight of the alloy, less than or equal to 0.045 percent of P, less than or equal to 0.045 percent of S, and the balance of Fe and inevitable impurities, wherein the content of the impurities is less than or equal to 0.04 percent.
8. The strengthening method for adding vanadium-titanium balls in the smelting process of construction steel bars according to claim 1, which is characterized in that: in the step (5), the rolling specification is one of phi 12mm multiplied by 4 slitting rolling, phi 14 multiplied by 4 slitting rolling, phi 16mm multiplied by 2 slitting rolling, phi 20-phi 22mm multiplied by 2 slitting rolling, phi 25mm and phi 28 mm; the initial rolling temperature of the rolling is 1065-1080 ℃, and the final rolling temperature is 930-950 ℃.
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| CN113802044B (en) * | 2021-08-02 | 2022-05-24 | 河钢股份有限公司承德分公司 | Alloying method of high-strength anti-seismic steel bar |
| CN114606427A (en) * | 2022-02-16 | 2022-06-10 | 首钢集团有限公司 | HRB400E anti-seismic reinforcing steel bar and preparation method thereof and HRB400E anti-seismic reinforcing steel bar |
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