阅读说明：本技术 一种超高拉速含铌hrb400e螺纹钢及其生产工艺 (Ultra-high pulling speed niobium-containing HRB400E deformed steel bar and production process thereof ) 是由 郭春光 张汉山 于 2020-06-19 设计创作，主要内容包括：本发明提供了一种超高拉速含铌HRB400E螺纹钢及其生产工艺,其重量百分比及化学成分为：C：0.16％～0.22％,Si：0.20％～0.50％,Mn：0.30％～0.60％,P：≤0.025％,S：≤0.025％,Cr：≤0.35％,Mo：0.20％～0.40％,余量为Fe及不可避免残余元素；具体的生产工艺为：钢水冶炼、连铸、连铸坯加热、轧制钢筋。该方法通过成分优化设计和炼钢、精炼、连铸和轧钢工艺优化,解决国内目前在含铌螺纹钢生产过程中,普遍存在的铸坯质量问题和铸机降速生产才能保证不出漏钢事故的问题。(The invention provides an ultra-high pulling speed niobium-containing HRB400E deformed steel bar and a production process thereof, wherein the deformed steel bar comprises the following chemical components in percentage by weight: c: 0.16% -0.22%, Si: 0.20-0.50%, Mn: 0.30% -0.60%, P: less than or equal to 0.025 percent, S: less than or equal to 0.025 percent, Cr: less than or equal to 0.35 percent, Mo: 0.20 to 0.40 percent of the total weight of the alloy, and the balance of Fe and inevitable residual elements; the specific production process comprises the following steps: smelting molten steel, continuous casting, heating continuous casting billets and rolling reinforcing steel bars. The method solves the problems that the casting blank quality problem and the steel leakage accident can not be guaranteed only by the speed reduction production of a casting machine in the prior production process of the niobium-containing deformed steel bar at home through the optimization design of components and the optimization of steel making, refining, continuous casting and steel rolling processes.)

1. The ultra-high pulling speed niobium-containing HRB400E deformed steel bar is characterized by comprising the following chemical components in percentage by weight:

c: 0.22 to 0.245 percent, Si: 0.35-0.45%, Mn: 1.15% -1.30%, P: less than or equal to 0.04 percent, S: less than or equal to 0.025 percent, Nb: 0.005-0.01 percent, and the balance of Fe and inevitable residual elements.

2. The ultra-high pulling speed niobium-containing HRB400E deformed steel bar as claimed in claim 1, wherein the weight percentage and chemical composition are as follows:

c: 0.22 to 0.245 percent, Si: 0.35-0.45%, Mn: 1.15% -1.25%, P: less than or equal to 0.04 percent, S: less than or equal to 0.025 percent, Nb: 0.005-0.01 percent, and the balance of Fe and inevitable residual elements.

3. The ultra-high pulling speed niobium-containing HRB400E deformed steel bar as claimed in claim 1, wherein the weight percentage and chemical composition are as follows:

c: 0.22 to 0.245 percent, Si: 0.35-0.45%, Mn: 1.20% -1.30%, P: less than or equal to 0.04 percent, S: less than or equal to 0.025 percent, Nb: 0.005-0.01 percent, and the balance of Fe and inevitable residual elements.

4. The ultra-high pulling speed niobium-containing HRB400E deformed steel bar of claim 1, wherein: the weight percentage and chemical components are as follows: c: 0.23%, Si: 0.40%, Mn: 1.20%, P: less than or equal to 0.025 percent, S: less than or equal to 0.025 percent, Cr: less than or equal to 0.35 percent, Nb: 0.006%, the balance being Fe and unavoidable residual elements.

5. The ultra-high pulling speed niobium-containing HRB400E deformed steel bar as claimed in claim 1, wherein the chemical composition is as follows: ceq: 0.41 to 0.47 percent.

6. The process for producing the ultra-high pulling speed niobium-containing HRB400E deformed steel bar as claimed in claim 1, wherein the process comprises the steps of:

s1 molten steel smelting

Smelting molten iron and/or scrap steel materials by a converter or an electric furnace to obtain molten steel; when the condition is satisfied: controlling the mass fraction of oxygen in molten steel according to grades and tapping, wherein the temperature is 1615-1625 ℃, the mass fraction of C is less than or equal to 0.06%, the mass fraction of P is less than or equal to 0.02%, and the mass fraction of sulfur is less than or equal to 0.025%; during tapping, adding Si iron, Mn iron and Nb iron alloy, after tapping, blowing argon through LF according to the chemical components of the niobium-containing HRB400E deformed steel, and adding alloy bulk cargo to adjust the contents of C, Si and Mn elements in molten steel;

s2 continuous casting

The LF refined qualified molten steel is continuously cast in a whole-process protection mode, the temperature of a tundish is 1515-1535 ℃, the drawing speed is more than or equal to 4.0m/s, D-type inclusions in the produced continuous casting square billet steel are less than or equal to 2.0 grade, and Ds-type inclusions are less than or equal to 2.0 grade; the loosening and cracking grade is less than or equal to 1.5 grade, and the macroscopic defect meets the requirement of a qualified continuous casting billet;

s3 continuous casting billet heating

The continuous casting billet is hot-charged at the temperature of 1100-1140 ℃ in a heating soaking section of a steel rolling heating furnace, and the heating time is 60-90 min; or the continuous casting billet is cold-packed at the temperature of 1120-1160 ℃ in the heating soaking section of the steel rolling heating furnace, and the heating time is cold-packed for 80-110 min;

s4 Rolling reinforcing bar

And continuously rolling the heated continuous casting blank, controlling the initial rolling temperature to be 980-1020 ℃, obtaining a rolled steel bar according to the dimension specification of the wire rod and the final rolling temperature to be 960-1000 ℃, and blowing and cooling the rolled steel bar in the air by a fan to obtain the ultra-high pulling speed niobium-containing HRB400E deformed steel bar.

7. The process for producing ultra-high pulling speed niobium-containing HRB400E deformed steel bar as claimed in claim 6, wherein: in step S1, the mass fraction of oxygen in the molten steel is controlled to be three grades, wherein the oxygen content is larger than 550ppm, 300ppm to 550ppm and less than or equal to 300ppm respectively.

Technical Field

The invention belongs to the technical field of steel preparation, and particularly relates to ultra-high pulling speed niobium-containing HRB400E deformed steel bar and a production process thereof.

Background

At present, manufacturers using a large amount of niobium-containing deformed steel bars in China can replace vanadium to perform alloy strengthening, cracks and stripping are easy to generate in the production process, the pulling speed is often low, and the production efficiency is influenced, for example, Kun steel R9M direct-arc 5-machine 5-flow small square billet casting machines are cast into small square billets with the cross sections of 150mm multiplied by 150mm, tundish molten steel is cast at low superheat degree (15-30 ℃) and typical pulling speed (2.6-2.8 m/min), secondary cooling is performed in an inter-cooling water distribution mode, the straightening temperature of the casting billets is higher than 1000 ℃, and the casting billets are ensured to have no cracks.

Disclosure of Invention

The invention provides a production process of ultra-high pulling speed niobium-containing HRB400E deformed steel bar in view of the blank problem of the prior domestic hot rolling polished round refractory steel bar production process, and the method solves the problems of casting blank quality and steel leakage accident which can be ensured only by the speed reduction production of a casting machine in the domestic niobium-containing deformed steel bar production process through component optimization design and optimization of steel making, refining, continuous casting and steel rolling processes.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides ultra-high pulling speed niobium-containing HRB400E deformed steel, which comprises the following chemical components in percentage by weight: c: 0.22 to 0.245 percent, Si: 0.35-0.45%, Mn: 1.15% -1.30%, P: less than or equal to 0.04 percent, S: less than or equal to 0.025 percent, Nb: 0.005-0.01 percent, and the balance of Fe and inevitable residual elements.

The ultra-high pulling speed niobium-containing HRB400E deformed steel comprises the following chemical components in percentage by weight: c: 0.22 to 0.245 percent, Si: 0.35-0.45%, Mn: 1.15% -1.25%, P: less than or equal to 0.04 percent, S: less than or equal to 0.025 percent, Nb: 0.005-0.01 percent, and the balance of Fe and inevitable residual elements.

The ultra-high pulling speed niobium-containing HRB400E deformed steel comprises the following chemical components in percentage by weight:

c: 0.22 to 0.245 percent, Si: 0.35-0.45%, Mn: 1.20% -1.30%, P: less than or equal to 0.04 percent, S: less than or equal to 0.025 percent, Nb: 0.005-0.01 percent, and the balance of Fe and inevitable residual elements.

The ultra-high pulling speed niobium-containing HRB400E deformed steel comprises the following chemical components in percentage by weight: c: 0.23%, Si: 0.40%, Mn: 1.20%, P: less than or equal to 0.025 percent, S: less than or equal to 0.025 percent, Cr: less than or equal to 0.35 percent, Nb: 0.006%, the balance being Fe and unavoidable residual elements.

The ultra-high pulling speed niobium-containing HRB400E deformed steel comprises the following chemical components: ceq: 0.41 to 0.47 percent.

The production process of the ultra-high pulling speed niobium-containing HRB400E deformed steel bar comprises the following steps:

s1 molten steel smelting

Smelting molten iron and/or scrap steel materials by a converter or an electric furnace to obtain molten steel; when the condition is satisfied: controlling the mass fraction of oxygen in molten steel according to grades and tapping, wherein the temperature is 1615-1625 ℃, the mass fraction of C is less than or equal to 0.06%, the mass fraction of P is less than or equal to 0.02%, and the mass fraction of sulfur is less than or equal to 0.025%; during tapping, adding Si iron, Mn iron and Nb iron alloy, after tapping, blowing argon through LF according to the chemical components of the niobium-containing HRB400E deformed steel, and adding alloy bulk cargo to adjust the contents of C, Si and Mn elements in molten steel;

s2 continuous casting

The LF refined qualified molten steel is continuously cast in a whole-process protection mode, the temperature of a tundish is 1515-1535 ℃, the drawing speed is more than or equal to 4.0m/s, D-type inclusions in the produced continuous casting square billet steel are less than or equal to 2.0 grade, and Ds-type inclusions are less than or equal to 2.0 grade; the loosening and cracking grade is less than or equal to 1.5 grade, and the macroscopic defect meets the requirement of a qualified continuous casting billet;

s3 continuous casting billet heating

The continuous casting billet is hot-charged at the temperature of 1100-1140 ℃ in a heating soaking section of a steel rolling heating furnace, and the heating time is 60-90 min; or the continuous casting billet is cold-packed at the temperature of 1120-1160 ℃ in the heating soaking section of the steel rolling heating furnace, and the heating time is cold-packed for 80-110 min;

s4 Rolling reinforcing bar

And continuously rolling the heated continuous casting blank, controlling the initial rolling temperature to be 980-1020 ℃, obtaining a rolled steel bar according to the dimension specification of the wire rod and the final rolling temperature to be 960-1000 ℃, and blowing and cooling the rolled steel bar in the air by a fan to obtain the ultra-high pulling speed niobium-containing HRB400E deformed steel bar.

In the production process of the ultra-high pulling speed niobium-containing HRB400E thread steel, the mass fraction of oxygen in the molten steel is controlled to be three grades in step S1, wherein the oxygen content is more than 550ppm, 300ppm to 550ppm and less than or equal to 300ppm respectively.

Compared with the prior art, the invention has the following beneficial effects:

the invention realizes the production of HRB400(E) twisted steel with a drawing speed of more than 4m/min and a square billet section of 155mm by 155 mm; the influence of the shrinkage characteristic of the niobium content in the steel on the continuous casting high drawing speed is reduced, the difficulty in condensing HRB400(E) threaded steel bars of the continuous casting blank at the drawing speed of more than 4m/min is solved, and the common casting blank defects such as surface cracks, central cracks and the like of casting blanks produced by the HRB400(E) threaded steel bars containing niobium are eliminated; the current situation that the breakout accident is easy to occur when the production of the niobium-containing HRB400(E) twisted steel is at the pulling speed of more than 4m/min is reduced.

Detailed Description

The technical solution of the present invention is further illustrated by the following examples, but the scope of the present invention is not limited thereto.