阅读说明：本技术 一种高延耐蚀钢筋生产方法 (Production method of high-ductility corrosion-resistant steel bar ) 是由 郭庆峰 伍永锐 王彬 于 2021-06-07 设计创作，主要内容包括：本申请公开了一种高延耐蚀钢筋生产方法,采用烧结矿和球团矿获得铁水,可提高钢筋强度,并将铁水和废钢进行冶炼得钢水,在冶炼时加入白云石和石灰以提高钢水纯度,在冶炼出钢过程中加入硅锰合金、硅氮合金、增碳剂、钒氮合金实现钢水的脱氧合金化,通过底吹氩确保钢水混合物成分的均匀性,最后对连续铸钢所得的钢坯先后进行粗轧、中轧及精轧得钢筋,其中精轧过程采用高耐磨性复合碳化物轧辊和控温工艺,可确保钢筋成品的耐腐蚀性和塑韧性,再将钢筋进行冷却后即可得到钢筋成品。该钢筋生产采用较低的C及Ceq成分设计,采用较少的V添加甚至无V添加的生产技术,达到提高钢筋延性和焊接性能、减少贵重资源消耗,实现建筑用钢的绿色化生产。(The application discloses a method for producing high-ductility corrosion-resistant steel bars, which adopts sintered ores and pellets to obtain molten iron, can improve the strength of the steel bars, and smelt the molten iron and scrap steel to obtain molten steel, wherein dolomite and lime are added during smelting to improve the purity of the molten steel, silicon-manganese alloy, silicon-nitrogen alloy, carburant and vanadium-nitrogen alloy are added during smelting and tapping to realize deoxidation alloying of the molten steel, bottom blowing argon is used for ensuring the uniformity of components of a molten steel mixture, and finally rough rolling, intermediate rolling and finish rolling are carried out on steel billets obtained by continuous casting steel to obtain the steel bars, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature control process, so that the corrosion resistance and plastic toughness of the finished steel bars can be ensured, and the finished steel bars can be obtained after cooling the steel bars. The production of the steel bar adopts the design of lower C and Ceq components, adopts the production technology of less V addition or even no V addition, achieves the purposes of improving the ductility and the welding performance of the steel bar, reducing the consumption of valuable resources and realizing the green production of the steel for the building.)

1. A method for producing high-elongation corrosion-resistant steel bars is characterized by comprising the following steps:

sintering vanadium titano-magnetite to prepare sinter and roasting to prepare pellet;

mixing the sintered ore, the pellet ore and coke, and adding the mixture into a blast furnace to perform oxygen-enriched blowing smelting to obtain molten iron;

injecting the molten iron and the scrap steel into a converter for smelting, and adding dolomite and lime into the converter according to the content of P and S in the molten iron to obtain molten steel, wherein the molten iron is 135 +/-2 t, the scrap steel is 15 +/-1 t, and the smelting period is 25-30 minutes;

adding a silicon-manganese alloy, a silicon-nitrogen alloy, a carburant and a vanadium-nitrogen alloy into a ladle while transferring the molten steel into the ladle, and blowing argon into the bottom of the ladle to obtain a molten steel mixture;

adding the molten steel mixture into a continuous casting machine for continuous casting of steel to obtain a steel billet, wherein the flow number of the continuous casting machine is 8 flows, and the drawing speed is 3 m/min;

conveying the steel billet into a stepping heating furnace, heating to 1050 +/-30 ℃, pushing the steel billet discharged out of the furnace into a rolling mill at the speed of 2-3m/s, and sequentially carrying out rough rolling, medium rolling and finish rolling to obtain a steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature-controlled rolling process;

and cooling the reinforcing steel bars by a cooling device, then conveying the reinforcing steel bars to a cooling bed for air cooling to room temperature, and then cooling to room temperature by adopting an air cooling mode to obtain reinforcing steel bar finished products.

2. The method for producing ductile corrosion resistant steel bars according to claim 1, wherein said feeding of said molten steel mixture into a continuous casting machine for continuous casting of steel to obtain a steel slab is embodied as follows:

and a sleeve is communicated and arranged at the bottom of the steel ladle so as to introduce the molten steel mixture into a tundish of the continuous casting machine, the molten steel mixture is introduced into a crystallizer of the continuous casting machine through an intrusive water pipe at the bottom of the tundish, and casting powder is added into the crystallizer so as to obtain the steel billet.

3. The method for producing the high-elongation corrosion-resistant steel bar according to claim 1, wherein the steel bar obtained by pushing the steel billet discharged from the furnace into a rolling mill at a speed of 2-3m/s and then performing rough rolling, intermediate rolling and finish rolling is specifically as follows:

firstly, carrying out rough rolling treatment by 6 rough rolling mills, then carrying out medium rolling treatment by 6 medium rolling mills, and cooling the steel billet subjected to medium rolling treatment to 900 +/-20 ℃ in a water cooling mode;

and sending the cooled steel billet into a 6-frame finishing mill for finish rolling treatment to obtain the steel bar.

4. The method for producing the high-elongation corrosion-resistant reinforcing steel bar according to claim 1, wherein the step of conveying the reinforcing steel bar to a cooling bed for air cooling to room temperature after cooling the reinforcing steel bar by a cooling device comprises the following specific steps:

and cooling the reinforcing steel bars to 850 +/-20 ℃ through the 3-level cooling device, and then conveying the reinforcing steel bars to the cooling bed for air cooling to room temperature.

5. The method for producing high-elongation corrosion-resistant steel bars according to claim 1, wherein after the steel bar finished product is obtained by cooling to normal temperature in an air cooling manner, the method further comprises:

and sampling and detecting the finished reinforcing steel bar product.

Technical Field

The application relates to the field of novel materials, in particular to a production method of a high-ductility corrosion-resistant steel bar.

Background

The existing 400 MPa-grade steel bars are mainly prepared according to the 2 nd part of steel for reinforced concrete of GBT 1499.2-2018: HRB400E produced by hot rolling ribbed steel bar, the production process of which mainly depends on the strengthening action of C and V to achieve the purpose of improving the strength. The higher C content sacrifices the ductility of the product and is not beneficial to the bending processing of the steel bar, and the brittle fracture is easy to occur particularly in the construction under the cold condition; on the other hand, Ceq is increased, the welding performance is poor, and the safety of the steel bar component is influenced. V belongs to precious metals, and a large amount of V is added in the steel bar smelting production, so that the huge consumption and waste of rare resources are caused. In addition, the existing 400 MPa-level hot-rolled ribbed steel bar is mainly produced by adopting a common cast steel roller, and the surface of a rolled product has microcracks due to the aging of the surface of the roller in the middle and later stages of a rolling process, so that the corrosion resistance of the steel bar product is poor, and most of the surfaces have obvious corrosion phenomena when the engineering is not used. The corrosion on the surface of the steel bar has adverse effect on the binding force between the steel bar and the concrete, and even endangers the use safety of the building when the binding force is serious.

Disclosure of Invention

The application provides a production method of a high-ductility corrosion-resistant reinforcing steel bar, and solves the problems that the traditional reinforcing steel bar in the prior art is poor in ductility, not beneficial to bending processing, easy to brittle failure and poor in corrosion resistance during actual use.

In order to solve the technical problem, the application provides a method for producing high-elongation corrosion-resistant steel bars, which comprises the following steps:

sintering vanadium titano-magnetite to prepare sinter and roasting to prepare pellet;

mixing the sintered ore, the pellet ore and coke, and adding the mixture into a blast furnace to perform oxygen-enriched blowing smelting to obtain molten iron;

injecting the molten iron and the scrap steel into a converter for smelting, and adding dolomite and lime into the converter according to the content of P and S in the molten iron to obtain molten steel, wherein the molten iron is 135 +/-2 t, the scrap steel is 15 +/-1 t, and the smelting period is 25-30 minutes;

adding a silicon-manganese alloy, a silicon-nitrogen alloy, a carburant and a vanadium-nitrogen alloy into a ladle while transferring the molten steel into the ladle, and blowing argon into the bottom of the ladle to obtain a molten steel mixture;

adding the molten steel mixture into a continuous casting machine for continuous casting of steel to obtain a steel billet, wherein the flow number of the continuous casting machine is 8 flows, and the drawing speed is 3 m/min;

conveying the steel billet into a stepping heating furnace, heating to 1050 +/-30 ℃, pushing the steel billet discharged out of the furnace into a rolling mill at the speed of 2-3m/s, and sequentially carrying out rough rolling, medium rolling and finish rolling to obtain a steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature-controlled rolling process;

and cooling the reinforcing steel bars by a cooling device, then conveying the reinforcing steel bars to a cooling bed for air cooling to room temperature, and then cooling to room temperature by adopting an air cooling mode to obtain reinforcing steel bar finished products.

Preferably, the step of adding the molten steel mixture into a continuous casting machine for continuous casting of steel to obtain a steel billet is as follows:

and a sleeve is communicated and arranged at the bottom of the steel ladle so as to introduce the molten steel mixture into a tundish of the continuous casting machine, the molten steel mixture is introduced into a crystallizer of the continuous casting machine through an intrusive water pipe at the bottom of the tundish, and casting powder is added into the crystallizer so as to obtain the steel billet.

Preferably, the step of pushing the steel billet discharged from the furnace into a rolling mill at the speed of 2-3m/s to perform rough rolling, intermediate rolling and finish rolling in sequence to obtain the steel bar specifically comprises the following steps:

firstly, carrying out rough rolling treatment by 6 rough rolling mills, then carrying out medium rolling treatment by 6 medium rolling mills, and cooling the steel billet subjected to medium rolling treatment to 900 +/-20 ℃ in a water cooling mode;

and sending the cooled steel billet into a 6-frame finishing mill for finish rolling treatment to obtain the steel bar.

Preferably, the step of conveying the steel bars to a cooling bed for air cooling to room temperature after cooling the steel bars by a cooling device specifically comprises:

and cooling the reinforcing steel bars to 850 +/-20 ℃ through the 3-level cooling device, and then conveying the reinforcing steel bars to the cooling bed for air cooling to room temperature.

Preferably, after the reinforcing bar finished product is obtained by cooling to normal temperature in an air cooling manner, the method further includes:

and sampling and detecting the finished reinforcing steel bar product.

Compared with the prior art, the production method of the high-ductility corrosion-resistant reinforcing steel bar comprises the steps of sintering vanadium titano-magnetite to prepare sintered ore and roasting to prepare pellet ore; mixing sintered ore, pellet ore and coke, and adding the mixture into a blast furnace to perform oxygen-enriched blowing smelting to obtain molten iron; injecting molten iron and scrap steel into a converter for smelting, and adding dolomite and lime into the converter according to the content of P and S in the molten iron to obtain molten steel, wherein the molten iron is 135 +/-2 t, the scrap steel is 15 +/-1 t, and the smelting period is 25-30 minutes; adding a silicon-manganese alloy, a silicon-nitrogen alloy, a carburant and a vanadium-nitrogen alloy into a ladle while transferring the molten steel into the ladle, and blowing argon into the bottom of the ladle to obtain a molten steel mixture; adding the molten steel mixture into a continuous casting machine for continuous casting of steel to obtain a steel billet, wherein the flow number of the continuous casting machine is 8 flows, and the drawing speed is 3 m/min; conveying the steel billet into a stepping heating furnace, heating to 1050 +/-30 ℃, pushing the steel billet discharged out of the furnace into a rolling mill at the speed of 2-3m/s, and sequentially carrying out rough rolling, medium rolling and finish rolling to obtain the steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature-controlled rolling process; and cooling the reinforcing steel bars by a cooling device, conveying the reinforcing steel bars to a cooling bed for air cooling to room temperature, and cooling to room temperature by adopting an air cooling mode to obtain reinforcing steel bar finished products.

Therefore, the production method adopts the sintered ore and the pellet ore produced by mixing vanadium titano-magnetite to obtain high vanadium-titanium molten iron, can improve the strength of the steel bar and simultaneously save the consumption of valuable alloy resources, smelt the molten iron and waste steel to obtain molten steel, add dolomite and lime during smelting to improve the purity of the molten steel, simultaneously add silicon-manganese alloy, silicon-nitrogen alloy, carburant and vanadium-nitrogen alloy during smelting and tapping to realize the deoxidation alloying of the molten steel, ensure the uniformity of the components of the molten steel mixture by bottom argon blowing, prevent the secondary oxidation of the molten steel by adopting the whole protective casting process during continuous casting, finally precisely heat the steel billet obtained by continuous casting, and sequentially carry out rough rolling, medium rolling and finish rolling to obtain the steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature-control rolling process, and can greatly improve the surface quality of the product, And refining the crystal grains to ensure the corrosion resistance and the plastic toughness of the finished product of the steel bar, and then cooling the steel bar to obtain the finished product of the steel bar. The production of the steel bar adopts the design of lower C and Ceq components, adopts the production technology of less V addition or even no V addition, achieves the purposes of improving the ductility and the welding performance of the steel bar and reducing the consumption of valuable resources, realizes the green production of high-quality building steel, and has great significance for promoting the structure adjustment and transformation upgrading of the steel industry and the building industry.

Drawings

In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments are briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without making any inventive changes.

Fig. 1 is a flow chart of a method for producing high-elongation corrosion-resistant steel bars according to an embodiment of the present invention.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings.

The core of the application is to provide a production method of the high-ductility corrosion-resistant steel bar, and the problems that the traditional steel bar in the prior art is poor in ductility, not beneficial to bending processing, easy to brittle failure and poor in corrosion performance in actual use can be solved.

Fig. 1 is a flow chart of a method for producing high-elongation corrosion-resistant steel bars according to an embodiment of the present invention, as shown in fig. 1, the method includes the following steps:

s101: sintering vanadium titano-magnetite to prepare sinter and roasting to prepare pellet.

S102: and mixing the sintered ore, the pellet ore and the coke, and then adding the mixture into a blast furnace for oxygen-enriched blowing smelting to obtain molten iron.

The obtained molten iron contains 4.0-5.5% of C, 0.20-0.70% of Si, 0.20-0.40% of Mn, less than or equal to 0.070% of P, less than or equal to 0.040% of S, 0.10-0.30% of V, and the temperature of the molten iron is more than or equal to 1250 ℃.

S103: injecting molten iron and scrap steel into a converter for smelting, and adding dolomite and lime into the converter according to the content of P and S in the molten iron to obtain molten steel, wherein the molten iron is 135 +/-2 t, the scrap steel is 15 +/-1 t, and the smelting period is 25-30 minutes.

The addition of dolomite and lime (lime) ([ Si ]% hot metal x 2.14 x R (yield strength) × hot metal charge x 1000/CaO% lime, CaO% lime being the percentage of available CaO in lime; during actual smelting, the smelting time can be set to be 28 minutes, a converter oxygen lance for smelting adopts a 5-hole nozzle, and the included angle is 12.5-14 degrees, so that slag is generated during slag splashing, impurities are oxidized into gas to escape or into oxides to form slag with added flux, and the purity is improved to obtain molten steel.

S104: and (3) adding a silicon-manganese alloy, a silicon-nitrogen alloy, a carburant and a vanadium-nitrogen alloy into the ladle while transferring the molten steel into the ladle, and blowing argon into the bottom of the ladle to obtain a molten steel mixture.

The purpose of adding the silicon-manganese alloy, the silicon-nitrogen alloy, the recarburizing agent and the vanadium-nitrogen alloy is to realize the deoxidation alloying of the molten steel, and the purpose of bottom argon blowing is to enhance the stirring and improve the uniformity of each component in the molten steel mixture. The adding amount of the silicon-manganese alloy is (target value-residual value) × 1000 tapping amount/(alloy content) × alloy recovery rate), the target value is a set value, and the residual value is a value for detecting residual manganese in the molten steel at the end point. The gas flow and the pressure of Ar after tapping ensure that the molten steel does not leak naked, and Ar is blown for 3 minutes after tapping, and then temperature measurement and sampling are carried out; the temperature after argon blowing is controlled to be 1560-1580 ℃, and according to the sampling analysis result, the contents of C, Si, P, S and V are 0.15-0.20%, 0.30-0.50%, 1.30-1.50%, less than or equal to 0.030% and 0.010-0.020%.

S105: and adding the molten steel mixture into a continuous casting machine for continuous casting of steel to obtain a steel billet, wherein the flow number of the continuous casting machine is 8 flows, and the drawing speed is 3 m/min.

On the basis of the above examples, as a preferred embodiment, the molten steel mixture is fed into a continuous casting machine for continuous casting of steel to obtain a steel slab, specifically:

and a sleeve is communicated and arranged at the bottom of the steel ladle so as to introduce the molten steel mixture into a tundish of a continuous casting machine, the molten steel mixture is introduced into a crystallizer of the continuous casting machine through an intrusive water pipe at the bottom of the tundish, and casting powder is added into the crystallizer so as to obtain a steel billet. The measures can prevent molten steel from being oxidized, ensure that the molten steel is pure, and the size of the cast billet is 165mm by 12000 mm.

S106: and conveying the steel billet into a stepping heating furnace, heating to 1050 +/-30 ℃, pushing the steel billet discharged from the furnace into a rolling mill at the speed of 2-3m/s, and sequentially carrying out rough rolling, medium rolling and finish rolling to obtain the steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature-controlled rolling process.

On the basis of the above examples, as a preferred embodiment, pushing the discharged steel slab into the rolling mill at a speed of 2-3m/s to perform rough rolling, intermediate rolling and finish rolling in sequence to obtain the steel bar specifically:

firstly, carrying out rough rolling treatment by 6 rough rolling mills, then carrying out medium rolling treatment by 6 medium rolling mills, and cooling the steel billet subjected to medium rolling treatment to 900 +/-20 ℃ by a water cooling mode to realize temperature-controlled rolling so as to achieve the purposes of refining crystal grains and improving the plastic toughness of the product;

and (3) sending the cooled steel billet into a 6-frame finishing mill for finish rolling treatment to obtain the steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller technology, so that the surface quality of the product is greatly improved.

The method comprises the following steps of sequentially processing through a 6-frame roughing mill and a 6-frame middle rolling mill, accurately controlling the temperature through an intelligent water cooling device, entering a 6-frame finishing mill under the condition of 900 +/-20 ℃, fully deforming and refining austenite grains through multi-pass rolling in an uncrystallized area so as to generate a large amount of dislocation substructures and deformation bands in the austenite grains, creating conditions for a large amount of nucleation of the ferrite grains in gamma → alpha phase transition, and achieving the purpose of fully refining the ferrite grains; on the other hand, the microalloy elements are subjected to strain-induced dispersion precipitation on ferrite grains through deformation, so that the precipitation strengthening effect of carbonitride precipitated particles is improved, and the aim of improving the strength is fulfilled. The rear 4 finishing mills all adopt high-wear-resistance composite carbide rollers and a temperature-controlled rolling process technology, the service cycle of a single rolling process is improved by 4-5 times compared with that of a common cast steel roller, the surface quality of a product is obviously improved, the surface smoothness of the product is high, the product is corrosion-resistant, and the appearance is attractive.

S107: and cooling the reinforcing steel bars by a cooling device, conveying the reinforcing steel bars to a cooling bed for air cooling to room temperature, and cooling to room temperature by adopting an air cooling mode to obtain reinforcing steel bar finished products.

As a preferred embodiment, the step of conveying the steel bars to a cooling bed for air cooling to room temperature after cooling the steel bars by a cooling device is specifically as follows:

the reinforcing steel bars are cooled to 850 +/-20 ℃ by a cooling device and then conveyed to a cooling bed for air cooling to room temperature.

The cooling adopts a graded cooling control process, the detailed steps of the graded cooling are divided into 3 grades, namely, strong cooling, red returning, inter-cooling, red returning, weak cooling and red returning, the temperature range of each grade is determined according to the continuous production process, the time is determined by the length of the water tank and the rolling speed, the length of the water tank of each grade can be adjusted according to the parameters of the water quantity of a switch nozzle and the like required, the temperature of an upper cooling bed is accurately controlled to be 850 +/-20 ℃, and the uniform and stable performance of the reinforcing steel bar product is ensured. 3 level cooling process avoids the forced cooling to lead to reinforcing bar top layer closed loop martensite structure to worsen reinforcing bar plasticity and toughness when fully restraining the crystal grain to grow up, through suitable water-cooling temperature interval, guarantees that the reinforcing bar top layer generates compact oxide layer to hinder the reinforcing bar corrosion rate.

In order to ensure the quality and the relevant performance of the finished reinforcing steel bar product, on the basis of the above embodiment, as a preferable implementation mode, after the finished reinforcing steel bar product is cooled to normal temperature by adopting an air cooling mode, the method further comprises the following steps:

and sampling and detecting the finished product of the reinforcing steel bar.

Comparison of main technical indexes of product

The application provides a production method of a high-ductility corrosion-resistant reinforcing steel bar, which adopts sintered ore and pellet ore produced by matching vanadium-titanium magnetite to obtain high-vanadium-titanium molten iron, can improve the strength of the reinforcing steel bar, smelt the molten iron and scrap steel to obtain molten steel, add dolomite and lime during smelting to improve the purity of the molten steel, simultaneously add silicon-manganese alloy, silicon-nitrogen alloy, recarburizer and vanadium-nitrogen alloy during smelting and tapping to realize the deoxidation alloying of the molten steel, ensure the uniformity of the components of the molten steel mixture by bottom blowing argon, protect and cast in the whole continuous casting process, precisely heat a billet obtained by continuously casting steel, and sequentially perform rough rolling, intermediate rolling and finish rolling to obtain the reinforcing steel bar, wherein the finish rolling process adopts a high-wear-resistance composite carbide roller and a temperature control rolling process, can improve the surface quality of the product, refine crystal grains, and ensure the corrosion resistance and the plastic toughness of a reinforcing steel bar finished product, and cooling the reinforcing steel bar to obtain a finished reinforcing steel bar product. The production of the steel bar adopts the design of lower C and Ceq components, adopts the production technology of less V addition or even no V addition, achieves the purposes of improving the ductility and the welding performance of the steel bar and reducing the consumption of valuable resources, realizes the green production of high-quality building steel, and has great significance for promoting the structure adjustment and transformation upgrading of the steel industry and the building industry.

Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the application and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims.

It will be understood that the present application is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The above-described embodiments of the present application do not limit the scope of the present application.