阅读说明：本技术 一种psb830精轧螺纹钢筋及其生产方法 (PSB830 finish-rolled twisted steel and production method thereof ) 是由 李建宾 秦小梅 田力 郭志春 钦祥斗 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种PSB830精轧螺纹钢筋及其生产方法,涉及钢筋生产技术领域,其化学成分及质量百分比如下：C：0.43%～0.48%,Si：1.60%～1.80%,Mn：0.90%～1.00%,(Cr+Ni+Cu)≤0.10%,Nb：0.01%～0.025%,V：0.125%～0.155%,P≤0.020%,S≤0.015%,N：75～110ppm,余量为Fe及不可避免的杂质。保证了钢材整个截面微观组织的细化和均匀化,在保证精轧螺纹钢筋的强度的同时提高塑韧性,具有良好的力学综合性能。(The invention discloses a PSB830 finish-rolled twisted steel and a production method thereof, relating to the technical field of steel bar production, wherein the PSB830 finish-rolled twisted steel comprises the following chemical components in percentage by mass: c: 0.43% -0.48%, Si: 1.60% -1.80%, Mn: 0.90-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.01% -0.025%, V: 0.125-0.155%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 110ppm, and the balance of Fe and inevitable impurities. The refining and homogenization of the microstructure of the whole section of the steel are ensured, the ductility and toughness are improved while the strength of the finish-rolled twisted steel is ensured, and the finish-rolled twisted steel has good mechanical comprehensive performance.)

1. The PSB830 finish-rolled threaded steel bar is characterized by comprising the following chemical components in percentage by mass: c: 0.43% -0.48%, Si: 1.60% -1.80%, Mn: 0.90-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.01% -0.025%, V: 0.125-0.155%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 110ppm, and the balance of Fe and inevitable impurities.

2. The PSB830 finish rolled twisted steel according to claim 1, wherein the PSB830 finish rolled twisted steel comprises the following chemical components in percentage by mass: c: 0.43 to 0.447%, Si: 1.62-1.68%, Mn: 0.90-0.95%, not more than 0.10% of (Cr + Ni + Cu), Nb: 0.01% -0.017%, V: 0.127-0.135%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 90ppm, and the balance of Fe and inevitable impurities.

3. The PSB830 finish rolled twisted steel according to claim 1, wherein the PSB830 finish rolled twisted steel comprises the following chemical components in percentage by mass: c: 0.452 to 0.48%, Si: 1.66% -1.80%, Mn: 0.93-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.015% -0.020%, V: 0.135-0.145%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 80 to 93ppm, and the balance of Fe and inevitable impurities.

4. The PSB830 finish rolled twisted steel according to claim 1, wherein: the specification of the finished product of the twisted steel is phi 25mm or phi 32mm, the allowable deviation of the length of the finished product is 0+20mm, the bending degree of the steel per meter is less than or equal to 4mm, and the total bending degree is less than or equal to 0.4% of the total length of the steel.

5. A PSB830 finish-rolled twisted steel production method as set forth in claim 1, comprising electric furnace smelting-LF furnace refining treatment-VD treatment-continuous casting-slab heating-rolling-controlled cooling after rolling, characterized in that:

steel making: smelting by an electric furnace, wherein the end point of the electric furnace is controlled to be more than or equal to 0.04 percent of C and less than or equal to 0.013 percent of P; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is more than 30 min; VD vacuum treatment is carried out, the vacuum degree is less than or equal to 1mbar, and the holding time is more than 12 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium rod core-spun wires for 50-150 m, and then statically stirring for more than 15 min;

continuous casting: the temperature of the first ladle is 1535-1550 ℃, the temperature of the continuous casting furnace secondary ladle is 1525-1540 ℃, the liquidus temperature is 1480 ℃, and the temperature is overheatedThe temperature is 10-40 ℃; cross section 150 x 150mm²The drawing speed is 2.0-2.4 m/min, full-protection casting is adopted for continuous casting, electromagnetic stirring is carried out, the liquid level of a tundish and a crystallizer is ensured to be stable, and the centering and the insertion depth of an invasive water gap are ensured;

rolling: the furnace temperature of the preheating section of the heating furnace before rolling is less than or equal to 900 ℃, the furnace temperature of the heating section is 1120-1180 ℃, and the furnace temperature of the soaking section is 1120-1200 ℃; the initial rolling temperature is 1000-1050 ℃, the red returning temperature is 600-630 ℃, and the descaling pressure of high-pressure water is more than or equal to 15 MPa;

and (5) after rolling, controlling and cooling.

6. The method of claim 5, wherein the PSB830 finish-rolled reinforcing bar comprises: the crystallizer casting powder is 38Si7 casting powder, the tundish covering agent is TD-BA, and the YB/T2012 is executed on the external dimension and the surface quality of the continuous casting billet.

7. The method of claim 6, wherein the PSB830 finish-rolled reinforcing bar comprises: the production of phi 25mmPSB finish rolling twisted steel is as follows:

steel making: smelting by adopting an electric furnace, and controlling the end point of the electric furnace C: 0.05%, P: 0.010%; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is 30 min; VD vacuum processing is carried out, the vacuum degree is 1mba, and the holding time is 15 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium bar core-spun wires for 80 meters, and then statically stirring for 20 min;

continuous casting: the temperature of a first ladle is 1540 ℃, the temperature of a continuous casting furnace secondary ladle is 1530 ℃, the liquidus temperature is 1480 ℃, and the superheat degree is 20-30 ℃; cross section 150 x 150mm²The drawing speed is 2.2m/min, full-protection casting is adopted for continuous casting, the crystallizer casting powder is 38Si7 casting powder, the tundish covering agent adopts tundish covering agent TD-BA, electromagnetic stirring and non-stirring normal operation are guaranteed, the liquid level of a tundish and a crystallizer is guaranteed to be stable, the centering and inserting depth of an invasive water gap are guaranteed, and finally a continuous casting blank with excellent internal quality and the appearance size and the surface quality conforming to YB/T2012 is obtained;

rolling: the furnace temperature of the preheating section of the heating furnace is 900 ℃, the furnace temperature of the heating section is 1150 ℃, and the furnace temperature of the soaking section is 1170 ℃; the rolling temperature is 1020 ℃, the re-reddening temperature is 630 ℃, and the high-pressure water descaling pressure is 15 MPa;

and (5) after rolling, controlling and cooling.

8. The method of claim 6, wherein the PSB830 finish-rolled reinforcing bar comprises: producing phi 32mmPSB finish rolling twisted steel, which comprises the following steps:

steel making: smelting by adopting an electric furnace, and controlling the end point of the electric furnace C: 0.05%, P: 0.010%; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is 30 min; VD vacuum processing is carried out, the vacuum degree is 1mba, and the holding time is 15 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium bar core-spun wires for 80 meters, and then statically stirring for 20 min;

continuous casting: the temperature of a first ladle is 1540 ℃, the temperature of a continuous casting furnace secondary ladle is 1530 ℃, the liquidus temperature is 1480 ℃, and the superheat degree is 20-30 ℃; cross section 150 x 150mm²The drawing speed is 2.2m/min, full-protection casting is adopted for continuous casting, the crystallizer casting powder is 38Si7 casting powder, the tundish covering agent adopts tundish covering agent TD-BA, electromagnetic stirring and non-stirring normal operation are guaranteed, the liquid level of a tundish and a crystallizer is guaranteed to be stable, the centering and inserting depth of an invasive water gap are guaranteed, and finally a continuous casting blank with excellent internal quality and the appearance size and the surface quality conforming to YB/T2012 is obtained;

rolling: the furnace temperature of the preheating section of the heating furnace is 900 ℃, the furnace temperature of the heating section is 1160 ℃, and the furnace temperature of the soaking section is 1180 ℃; the rolling temperature is 1030 ℃, the red returning temperature is 620 ℃, and the high-pressure water descaling pressure is 15 MPa;

and (5) after rolling, controlling and cooling.

Technical Field

The invention relates to the technical field of steel bar production, in particular to a PSB830 finish-rolled twisted steel bar and a production method thereof.

Background

The finish-rolled twisted steel bar is a straight steel bar with large diameter, high strength and high dimensional accuracy, wherein external threads are rolled on the whole steel bar, and the steel bar is connected by screwing a connector with internal threads at any interface or anchored by screwing a nut with threads. The finish-rolled twisted steel is widely used for continuous beams and large frame structures in large-scale hydraulic engineering, industrial and civil buildings, highway, railway large-midspan bridges, nuclear power stations, ground anchors and other projects, has the advantages of simple and convenient connection and anchoring, strong adhesion, safe and reliable stretching and anchoring, convenient construction and the like, saves steel bars, and reduces the area and the weight of components. Because welding is avoided, the performance of the steel bar can not be restricted by weldability, and therefore, the high-strength steel bar can be produced by adopting various high-content alloy or heat treatment processes. With the improvement of application requirements, higher requirements are put forward on technical indexes such as elongation and the like of finish-rolled twisted steel, and the difficulty of on-line direct production is increased. The PSB 830-grade finish-rolled threaded steel bar is easy to have the problems of brittle fracture after rolling, low elongation and the like, and needs to be quenched and tempered offline, so that the production process is complicated, and the production cost of the finish-rolled threaded steel bar is increased.

Disclosure of Invention

In order to solve the technical problems, the invention provides a PSB830 finish-rolled twisted steel, which comprises the following chemical components in percentage by mass: c: 0.43% -0.48%, Si: 1.60% -1.80%, Mn: 0.90-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.01% -0.025%, V: 0.125-0.155%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 110ppm, and the balance of Fe and inevitable impurities.

The technical effects are as follows: the invention provides PSB830 finished finish-rolled twisted steel with specifications of phi 25mm and phi 32mm, and the finished finish-rolled twisted steel obtains ferrite grain size of more than 12 levels by establishing a new alloy system, rolling and controlling a cooling process after rolling, simultaneously ensures the refinement and homogenization of the microstructure of the whole section of steel, improves the ductility and toughness while ensuring the strength of the finish-rolled twisted steel, and has good mechanical comprehensive performance.

The technical scheme of the invention is further defined as follows:

the PSB830 finish-rolled twisted steel comprises the following chemical components in percentage by mass: c: 0.43 to 0.447%, Si: 1.62-1.68%, Mn: 0.90-0.95%, not more than 0.10% of (Cr + Ni + Cu), Nb: 0.03% -0.017%, V: 0.127-0.135%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 90ppm, and the balance of Fe and inevitable impurities.

The PSB830 finish-rolled twisted steel comprises the following chemical components in percentage by mass: c: 0.452 to 0.48%, Si: 1.66% -1.80%, Mn: 0.93-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.015% -0.020%, V: 0.135-0.145%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 80 to 93ppm, and the balance of Fe and inevitable impurities.

The PSB830 finish-rolled twisted steel has the specification of phi 25mm or phi 32mm, the allowable deviation of the length of a finished product is 0+20mm, the bending degree of the steel per meter is less than or equal to 4mm, and the total bending degree is less than or equal to 0.4% of the total length of the steel.

The invention also aims to provide a production method of the PSB830 finish-rolled twisted steel, which comprises the steps of electric furnace smelting, LF furnace refining treatment, VD treatment, continuous casting, slab heating, rolling, controlled cooling after rolling,

steel making: smelting by an electric furnace, wherein the end point of the electric furnace is controlled to be more than or equal to 0.04 percent of C and less than or equal to 0.013 percent of P; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is more than 30 min; VD vacuum treatment is carried out, the vacuum degree is less than or equal to 1mbar, and the holding time is more than 12 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium rod core-spun wires for 50-150 m, and then statically stirring for more than 15 min;

continuous casting: the temperature of a first ladle is 1535-1550 ℃, the temperature of a continuous casting furnace secondary ladle is 1525-1540 ℃, the liquidus temperature is 1480 ℃, and the superheat degree is 10-40 ℃; cross section 150 x 150mm²The drawing speed is 2.0-2.4 m/min, full-protection casting is adopted for continuous casting, electromagnetic stirring is carried out, the liquid level of a tundish and a crystallizer is ensured to be stable, and the centering and the insertion depth of an invasive water gap are ensured;

rolling: the furnace temperature of the preheating section of the heating furnace before rolling is less than or equal to 900 ℃, the furnace temperature of the heating section is 1120-1180 ℃, and the furnace temperature of the soaking section is 1120-1200 ℃; the initial rolling temperature is 1000-1050 ℃, the red returning temperature is 600-630 ℃, and the descaling pressure of high-pressure water is more than or equal to 15 MPa;

and (5) after rolling, controlling and cooling.

According to the production method of the PSB830 finish rolling twisted steel, the mold powder is 38Si7 mold powder, the tundish covering agent is TD-BA, and YB/T2012 is executed on the external dimension and the surface quality of a continuous casting billet.

The production method of the PSB830 finish-rolled twisted steel is used for producing phi 25mm PSB finish-rolled twisted steel, and comprises the following steps:

steel making: smelting by adopting an electric furnace, and controlling the end point of the electric furnace C: 0.05%, P: 0.010%; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is 30 min; VD vacuum processing is carried out, the vacuum degree is 1mba, and the holding time is 15 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium bar core-spun wires for 80 meters, and then statically stirring for 20 min;

continuous casting: first pack temperature1540 ℃, 1530 ℃ of a continuous casting furnace secondary ladle, 1480 ℃ of a liquidus temperature and 20-30 ℃ of superheat degree; cross section 150 x 150mm²The drawing speed is 2.2m/min, full-protection casting is adopted for continuous casting, the crystallizer casting powder is 38Si7 casting powder, the tundish covering agent adopts tundish covering agent TD-BA, electromagnetic stirring and non-stirring normal operation are guaranteed, the liquid level of a tundish and a crystallizer is guaranteed to be stable, the centering and inserting depth of an invasive water gap are guaranteed, and finally a continuous casting blank with excellent internal quality and the appearance size and the surface quality conforming to YB/T2012 is obtained;

rolling: the furnace temperature of the preheating section of the heating furnace is 900 ℃, the furnace temperature of the heating section is 1150 ℃, and the furnace temperature of the soaking section is 1170 ℃; the rolling temperature is 1020 ℃, the re-reddening temperature is 630 ℃, and the high-pressure water descaling pressure is 15 MPa;

and (5) after rolling, controlling and cooling.

The production method of the PSB830 finish-rolled twisted steel is used for producing the PSB finish-rolled twisted steel with the diameter of 32mm, and comprises the following steps:

steel making: smelting by adopting an electric furnace, and controlling the end point of the electric furnace C: 0.05%, P: 0.010%; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is 30 min; VD vacuum processing is carried out, the vacuum degree is 1mba, and the holding time is 15 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium bar core-spun wires for 80 meters, and then statically stirring for 20 min;

continuous casting: the temperature of a first ladle is 1540 ℃, the temperature of a continuous casting furnace secondary ladle is 1530 ℃, the liquidus temperature is 1480 ℃, and the superheat degree is 20-30 ℃; cross section 150 x 150mm²The drawing speed is 2.2m/min, full-protection casting is adopted for continuous casting, the crystallizer casting powder is 38Si7 casting powder, the tundish covering agent adopts tundish covering agent TD-BA, electromagnetic stirring and non-stirring normal operation are guaranteed, the liquid level of a tundish and a crystallizer is guaranteed to be stable, the centering and inserting depth of an invasive water gap are guaranteed, and finally a continuous casting blank with excellent internal quality and the appearance size and the surface quality conforming to YB/T2012 is obtained;

rolling: the furnace temperature of the preheating section of the heating furnace is 900 ℃, the furnace temperature of the heating section is 1160 ℃, and the furnace temperature of the soaking section is 1180 ℃; the rolling temperature is 1030 ℃, the red returning temperature is 620 ℃, and the high-pressure water descaling pressure is 15 MPa;

and (5) after rolling, controlling and cooling.

The invention has the beneficial effects that:

(1) the PSB830 finish-rolled twisted steel produced by the invention is well matched with a connector and a nut, is safe and reliable after being stressed, is simple and easy to anchor, does not need to be welded, improves the construction efficiency and is more and more widely applied;

(2) according to the invention, by adjusting the steel alloy components, the steel can be formed at one time through waste heat treatment after rolling, and offline quenching and tempering treatment is not needed, so that the processing technology is saved, and the production cost of finish-rolled twisted steel is reduced;

(3) the finish-rolled twisted steel obtained by the invention has excellent comprehensive performance, the yield strength Rel is more than or equal to 830MPa, the tensile strength Rm is more than or equal to 1030MPa, the elongation after fracture is more than or equal to 6 percent, and the total elongation under maximum force is more than or equal to 3.5 percent;

(4) the finish-rolled twisted steel designed by the invention has obvious economic benefit, for example, the finish-rolled twisted steel is used for replacing cold-drawn steel, the steel can be saved by 30-40%, and the economic benefit and the social benefit are obvious by omitting welding construction cost and anchorage device reduction cost.

Drawings

FIG. 1 is a typical structural morphology of a phi 25mm PSB830 finish-rolled threaded steel bar obtained in example 1 of the present invention under a metallographic microscope;

fig. 2 is a typical structural morphology diagram of a phi 32mm psb830 finish-rolled threaded steel bar obtained in example 2 of the present invention under a metallographic microscope.

Detailed Description

A PSB830 finish-rolled twisted steel comprises the following chemical components in percentage by mass: c: 0.43% -0.48%, Si: 1.60% -1.80%, Mn: 0.90-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.01% -0.025%, V: 0.125-0.155%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 110ppm, and the balance of Fe and inevitable impurities.

Preferably, the chemical components and the mass percentage are as follows: c: 0.43 to 0.447%, Si: 1.62-1.68%, Mn: 0.90-0.95%, not more than 0.10% of (Cr + Ni + Cu), Nb: 0.03% -0.017%, V: 0.127-0.135%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 75 to 90ppm, and the balance of Fe and inevitable impurities.

Or preferably, the chemical components and the mass percentage are as follows: c: 0.452 to 0.48%, Si: 1.66% -1.80%, Mn: 0.93-1.00 percent, (Cr + Ni + Cu) is less than or equal to 0.10 percent, Nb: 0.015% -0.020%, V: 0.135-0.145%, P is less than or equal to 0.020%, S is less than or equal to 0.015%, N: 80 to 93ppm, and the balance of Fe and inevitable impurities.

The production method of the steel bar comprises the following steps: electric furnace smelting, LF furnace refining treatment, VD treatment, continuous casting, slab heating, rolling, controlled cooling after rolling,

steel making: smelting by an electric furnace, wherein the end point of the electric furnace is controlled to be more than or equal to 0.04 percent of C and less than or equal to 0.013 percent of P; in the LF refining process, high-purity silicon carbide is used for diffusion deoxidation, and the refining time is more than 30 min; VD vacuum treatment is carried out, the vacuum degree is less than or equal to 1mbar, and the holding time is more than 12 min; after vacuum treatment, feeding manganese nitride wires to adjust the nitrogen content, then feeding pure calcium rod core-spun wires for 50-150 m, and then statically stirring for more than 15 min;

continuous casting: the temperature of a first ladle is 1535-1550 ℃, the temperature of a continuous casting furnace secondary ladle is 1525-1540 ℃, the liquidus temperature is 1480 ℃, and the superheat degree is 10-40 ℃; cross section 150 x 150mm²The drawing speed is 2.0-2.4 m/min, full-protection casting is adopted for continuous casting, electromagnetic stirring is carried out, the liquid level of a tundish and a crystallizer is ensured to be stable, the centering and inserting depth of an invasive water gap are ensured, the crystallizer casting powder is 38Si7 casting powder, a tundish covering agent is TD-BA, and YB/T2012 is executed on the overall dimension and the surface quality of a continuous casting billet;

rolling: the furnace temperature of the preheating section of the heating furnace before rolling is less than or equal to 900 ℃, the furnace temperature of the heating section is 1120-1180 ℃, and the furnace temperature of the soaking section is 1120-1200 ℃; the initial rolling temperature is 1000-1050 ℃, the red returning temperature is 600-630 ℃, and the descaling pressure of high-pressure water is more than or equal to 15 MPa;

and (5) after rolling, controlling and cooling.

The specification of the finished product of the twisted steel is phi 25mm or phi 32mm, the allowable deviation of the length of the finished product is 0+20mm, the bending degree of the steel per meter is less than or equal to 4mm, and the total bending degree is less than or equal to 0.4% of the total length of the steel.