阅读说明：本技术 一种低硅高铝含硫钢的连铸生产方法 (Continuous casting production method of low-silicon high-aluminum sulfur-containing steel ) 是由 于飞 郭动动 管挺 张天 王海心 徐建飞 于 2021-09-22 设计创作，主要内容包括：本发明涉及一种低硅高铝含硫钢的连铸生产方法,包括首先采用精炼炉先脱硫再增硫的方法,具体为钢水精炼时先将硫脱至0.003％以下,之后先喂钙线再喂硫磺线调整硫含量；之后连铸采用开浇第一炉生产硅和铝范围宽的低硫钢种、开浇第二炉生产铝含量范围宽的低硅含硫钢种、开浇第三炉和连浇炉生产低硅高铝含硫钢的过渡生产方法。本发明采用精炼炉在常规脱氧脱硫后,采取首先加入钙线再喂硫磺线增硫的方法,使得喂入钢水中的钙元素首先与Al-(2)O-(3)反应生成钙铝酸盐,之后再喂入硫磺线,利用钢水中游离钙较低而产生的CaS较少的特点,有效地控制连铸液面波动,减少因液面波动超标产生的报废,减缓连铸水口结瘤的速度,从而大幅增加连浇炉数,降低生产成本。(The invention relates to a continuous casting production method of low-silicon high-aluminum sulfur-containing steel, which comprises the steps of firstly adopting a method of firstly desulfurizing and then increasing sulfur in a refining furnace, specifically, firstly desulfurizing the molten steel to be less than 0.003 percent during refining, and then feeding a calcium wire and then feeding a sulfur wire to adjust the sulfur content; and then the continuous casting adopts a transitional production method that the casting-on first furnace is adopted to produce low-sulfur steel with wide range of silicon and aluminum, the casting-on second furnace is adopted to produce low-silicon sulfur-containing steel with wide range of aluminum content, and the casting-on third furnace and the continuous casting furnace are adopted to produce low-silicon high-aluminum sulfur-containing steel. The invention adopts a refining furnace to increase the sulfur content by adding a calcium wire and feeding a sulfur wire after conventional deoxidation and desulfurization, so that calcium element fed into molten steel and Al are mixed 2 O 3 Reacting to form calcium aluminate, and thenAnd then feeding a sulfur line, effectively controlling the continuous casting liquid level fluctuation by utilizing the characteristic that the CaS generated by lower free calcium in the molten steel is less, reducing scrappage caused by the exceeding standard of the liquid level fluctuation and slowing down the speed of the accretion of a continuous casting water gap, thereby greatly increasing the number of continuous casting furnaces and reducing the production cost.)

1. A continuous casting production method of low-silicon high-aluminum sulfur-containing steel is characterized by comprising the following steps: when molten steel is refined, firstly, sulfur is removed to be below 0.003 percent, then, a calcium line is fed first, then a sulfur line is fed to adjust the sulfur content, continuous casting adopts a first furnace for casting to produce low-sulfur steel, a second furnace for casting to produce low-silicon sulfur-containing steel, a third furnace for casting and a subsequent continuous casting furnace to produce low-silicon high-aluminum sulfur-containing steel, and the method specifically comprises the following steps:

s1, casting the first furnace:

1) and the control requirement of the converter endpoint composition: c is less than or equal to 0.05 percent and P is less than or equal to 0.020 percent;

2) the refining adopts normal deoxidation and desulfurization and component adjustment operation, the components are adjusted to 0.04-0.07 percent of C, 0.08-0.12 percent of Si, 0.25-0.35 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.003 percent of S and 0.020-0.025 percent of Al;

3) feeding calcium wires into the steel ladle according to 2 m of ton steel, and soft blowing for 5 min;

4) feeding a sulfur wire into the molten steel ladle, and adjusting the S content in the molten steel from below 0.003% to 0.008-0.012%;

5) hoisting the molten steel to a continuous casting start, wherein the molten steel comprises 0.04-0.07% of component C, 0.08-0.12% of component Si, 0.25-0.35% of component Mn, less than or equal to 0.025% of component P, 0.008-0.012% of component S and 0.015-0.023% of component Al during ladle hoisting;

s2, casting a second furnace:

1) and the control requirement of the converter endpoint composition: c is less than or equal to 0.05 percent and P is less than or equal to 0.020 percent;

2) normal deoxidation and desulfurization and component adjustment operations are adopted in refining, and the components are adjusted to 0.04-0.07% of C, 0.06-0.08% of Si, 0.25-0.35% of Mn, less than or equal to 0.025% of P, less than or equal to 0.003% of S and 0.035-0.045% of Al;

3) feeding calcium wires into the steel ladle according to the ton steel of 1.5 meters, and soft-blowing for 5 min;

4) feeding a sulfur wire into the molten steel ladle to adjust the S content in the molten steel from below 0.003% to 0.018-0.025%;

5) hoisting the molten steel to a continuous casting start for casting, wherein the molten steel comprises 0.04-0.07% of component C, 0.06-0.08% of component Si, 0.25-0.35% of component Mn, less than or equal to 0.025% of component P, 0.018-0.025% of component S, and 0.033-0.041% of component Al during hoisting;

s3, casting a third furnace:

1) and the control requirement of the converter endpoint composition: c is less than or equal to 0.05 percent and P is less than or equal to 0.020 percent;

2) normal deoxidation and desulfurization and component adjustment operation are adopted in refining, and the components are adjusted to 0.04-0.07% of C, 0.04-0.08% of Si, 0.25-0.35% of Mn, less than or equal to 0.025% of P, less than or equal to 0.003% of S and 0.045-0.055% of Al;

3) feeding calcium wires into the steel ladle according to the ton steel of 1.5 meters, and soft-blowing for 5 min;

4) feeding a sulfur wire into the molten steel ladle to adjust the S content in the molten steel from below 0.003% to 0.018-0.025%;

5) and hoisting the molten steel to a continuous casting start for casting, wherein the molten steel comprises 0.04-0.07% of C, 0.04-0.08% of Si, 0.25-0.35% of Mn, less than or equal to 0.025% of P, 0.018-0.025% of S and 0.043-0.051% of Al during ladle hoisting.

Technical Field

The invention relates to the technical field of steelmaking continuous casting, in particular to a continuous casting production method of low-silicon high-aluminum sulfur-containing steel.

Background

The continuous casting steel is a technological process of utilizing the buffering action of tundish to continuously cast high-temperature molten steel into one or more metal cavities (crystallizers) with forced water cooling, solidifying and forming, and then secondary cooling to solidify and form a casting blank with a certain shape (specification), and is characterized by the continuity of the production process.

During specific operation, molten steel flows into the tundish from the ladle and then flows into the crystallizer from the tundish to form a primary blank shell, and the primary blank shell is drawn into a qualified casting blank by the blank drawing machine. The most remarkable characteristics are as follows: because of the buffer function of the tundish for storing the molten steel, the operation of replacing the steel containing barrel can be realized, so that the continuous casting can be realized by replacing the next steel containing barrel (containing the next furnace of molten steel) after the furnace of molten steel in the steel containing barrel is poured, and the production efficiency is improved.

The steel for the motor claw pole is a typical steel grade of low-silicon high-aluminum sulfur-containing steel, and with the development of industries such as new energy automobiles, the product quality requirement of the market on the steel for the motor claw pole is continuously improved. The control technology for controlling the liquid level fluctuation of the crystallizer in the continuous casting at present mainly comprises two main categories, one of which is a metering nozzle flow control technology, the method mainly takes measures of adjusting the casting speed and controlling the liquid level height of a tundish, the control precision is not high, and the liquid level fluctuation is more than or equal to +/-5 mm; the second is a stopper rod flow control technology, which adopts the scheme that a stopper rod moves up and down to change the size of steel flow to stabilize the liquid level of the crystallizer, and the fluctuation control precision of the liquid level of the crystallizer is less than or equal to +/-3 mm in the prior method. The fluctuation range of the liquid level of the crystallizer is small, and the condition that large-particle inclusions caused by slag entrapment in the drawing casting process exceed the standard can be avoided, so that the liquid level fluctuation of the crystallizer is stably controlled by adopting a stopper rod flow control technology in the continuous casting when the steel for the claw pole of the motor is produced at present. The steel for the claw pole of the motor comprises, by mass, 0.04-0.07% of main elements C, less than or equal to 0.08% of Si, 0.25-0.40% of Mn, less than or equal to 0.030% of P, 0.018-0.035% of S, 0.02-0.07% of Al, and belongs to the category of low-silicon high-aluminum sulfur-containing steel.

The casting time of the high-quality steel produced by continuous casting is about 15 furnaces generally, the high-quality steel from the third furnace to the 15 th furnace is called a continuous casting furnace, the secondary oxidation of the molten steel can not be completely avoided although a protective casting technology is adopted during the continuous casting of the low-silicon high-aluminum sulfur-containing steel, and simultaneously because the Si content in the components is low, Al generated by the mass oxidation of Al in the molten steel in the casting process is low₂O₃The nozzle of the stopper rod can be nodulated, thereby causing the liquid level of the crystallizer to fluctuate and even causing the crystallizer to stop flowing. Another method for controlling continuous casting pouring nodulation in the prior art is to feed a large amount of calcium wires into molten steel to ensure that Al generated in a tundish due to secondary oxidation₂O₃The calcium aluminate with low melting point is generated by the reaction with Ca, thereby solving the problem that Al2O3 gathers to block the water gap. However, for low-silicon high-aluminum sulfur-containing steel, as the molten steel S is 0.018-0.035%, CaS is generated by feeding calcium wires, and the CaS is accumulated at a stopper water gap to cause nodulation, so that the liquid level of a crystallizer fluctuates or the crystallizer is dead and stops casting.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects in the prior art, the invention provides a continuous casting production method of low-silicon high-aluminum sulfur-containing steel, which aims to solve the problems that a large amount of Al in molten steel of a low-silicon high-aluminum sulfur-containing steel casting furnace is oxidized into Al2O3 and CaS is generated after a pure Ca line is added, so that the liquid level fluctuation caused by the clogging of a stopper rod water gap is avoided, and the number of continuous casting furnaces is greatly increased.

The technical scheme adopted by the invention for solving the technical problems is as follows: a continuous casting production method of low-silicon high-aluminum sulfur-containing steel comprises the steps of firstly removing sulfur to be below 0.003 percent during molten steel refining, and then feeding a calcium line and then feeding a sulfur line to adjust the sulfur content; the continuous casting adopts a first furnace for casting to produce low-sulfur steel, a second furnace for casting to produce low-silicon sulfur-containing steel, a third furnace for casting and a subsequent continuous casting furnace to produce low-silicon high-aluminum sulfur-containing steel.

The composition of the three furnaces before casting is controlled as follows:

the continuous casting production method specifically comprises the following steps:

s1, casting the first furnace:

1) and the control requirement of the converter endpoint composition: c is less than or equal to 0.05 percent and P is less than or equal to 0.020 percent;

2) the refining adopts normal deoxidation and desulfurization and component adjustment operation, the components are adjusted to 0.04-0.07 percent of C, 0.08-0.12 percent of Si, 0.25-0.35 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.003 percent of S and 0.020-0.025 percent of Al;

3) feeding calcium wires into the steel ladle according to 2 m of ton steel, and soft blowing for 5 min;

4) feeding a sulfur wire into the molten steel ladle, and adjusting the S content in the molten steel from below 0.003% to 0.008-0.012%;

5) hoisting the molten steel to a continuous casting start, wherein the molten steel comprises 0.04-0.07% of component C, 0.08-0.12% of component Si, 0.25-0.35% of component Mn, less than or equal to 0.025% of component P, 0.008-0.012% of component S and 0.015-0.023% of component Al during ladle hoisting;

s2, casting a second furnace:

1) and the control requirement of the converter endpoint composition: c is less than or equal to 0.05 percent and P is less than or equal to 0.020 percent;

2) normal deoxidation and desulfurization and component adjustment operations are adopted in refining, and the components are adjusted to 0.04-0.07% of C, 0.06-0.08% of Si, 0.25-0.35% of Mn, less than or equal to 0.025% of P, less than or equal to 0.003% of S and 0.035-0.045% of Al;

3) feeding calcium wires into the steel ladle according to the ton steel of 1.5 meters, and soft-blowing for 5 min;

4) feeding a sulfur wire into the molten steel ladle to adjust the S content in the molten steel from below 0.003% to 0.018-0.025%;

5) hoisting the molten steel to a continuous casting start for casting, wherein the molten steel comprises 0.04-0.07% of component C, 0.06-0.08% of component Si, 0.25-0.35% of component Mn, less than or equal to 0.025% of component P, 0.018-0.025% of component S, and 0.033-0.041% of component Al during hoisting;

s3, casting a third furnace:

1) and the control requirement of the converter endpoint composition: c is less than or equal to 0.05 percent and P is less than or equal to 0.020 percent;

2) normal deoxidation and desulfurization and component adjustment operation are adopted in refining, and the components are adjusted to 0.04-0.07% of C, 0.04-0.08% of Si, 0.25-0.35% of Mn, less than or equal to 0.025% of P, less than or equal to 0.003% of S and 0.045-0.055% of Al;

3) feeding calcium wires into the steel ladle according to the ton steel of 1.5 meters, and soft-blowing for 5 min;

4) feeding a sulfur wire into the molten steel ladle to adjust the S content in the molten steel from below 0.003% to 0.018-0.025%;

5) and hoisting the molten steel to a continuous casting start for casting, wherein the molten steel comprises 0.04-0.07% of C, 0.04-0.08% of Si, 0.25-0.35% of Mn, less than or equal to 0.025% of P, 0.018-0.025% of S and 0.043-0.051% of Al during ladle hoisting.

In the scheme, the Si and the Al in the molten steel components need three-furnace transition, and the S in the molten steel components needs two-furnace transition.

The invention has the beneficial effects that:

(1) the invention adopts the method that after the conventional deoxidation and desulfurization are carried out by the refining furnace, the calcium wire is firstly added and then the sulfur wire is fed for increasing the sulfur, so that the calcium element fed into the molten steel can be firstly mixed with Al₂O₃Calcium aluminate is generated by reaction, and then the sulfur wire is fed, so that less CaS is generated in molten steel due to lower free calcium.

(2) The method provided by the invention can effectively control the continuous casting liquid level fluctuation and reduce the scrap caused by the overproof liquid level fluctuation.

(3) The method provided by the invention can effectively slow down the speed of the continuous casting nozzle nodulation, thereby greatly increasing the number of continuous casting furnaces and reducing the production cost.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a graph showing the position of a flow control stopper and the level of molten steel in a mold in the examples.

FIG. 2 is a graph showing the position of a flow control stopper and the level of molten steel in a mold in a comparative example.

Detailed Description

The continuous casting production method of the low-silicon high-aluminum sulfur-containing steel of the invention is specifically explained by the specific embodiment of matching a 120-ton converter with a 160-square continuous casting machine.

Example (b):

the method comprises the following specific steps:

1. the first furnace is started to be poured, and the operation process is as follows:

1) the converter end point components C are 0.04 percent and P is 0.018 percent;

2) refining by normal deoxidation and desulfurization and component adjustment operation, wherein the components are adjusted to 0.06 percent of C, 0.10 percent of Si, 0.31 percent of Mn, 0.020 percent of P, 0.002 percent of S and 0.025 percent of Al;

3) feeding 240 m calcium wire into the steel ladle, and soft blowing for 5 min:

4) feeding 100 m sulfur wire into the ladle to adjust the S content in the molten steel to 0.009%;

5) hoisting the molten steel to a continuous casting start ladle, wherein the molten steel comprises 0.06% of C, 0.10% of Si, 0.31% of Mn, 0.020% of P, 0.009% of S and 0.021% of Al during ladle hoisting;

6) and taking a finished product sample in the tundish to observe the aluminum loss, wherein the finished product sample C is 0.06 percent, Si is 0.09 percent, Mn is 0.31 percent, P is 0.020 percent, S is 0.009 percent, and Al is 0.017 percent, and compared with the ladle sample, the continuous casting aluminum loss is 0.004 percent.

2. And (3) starting a second furnace, wherein the operation process is as follows:

1) the converter end point component C is 0.05 percent, and the P is 0.016 percent;

2) refining with normal deoxidation and desulfurization and component regulation until C is 0.06%, Si is 0.08%, Mn is 0.30%, P is 0.019%, S is 0.003% and Al is 0.036%;

3) feeding a calcium wire for 180 meters into the steel ladle and soft-blowing for 5 min;

4) feeding a sulfur wire of 200 m into a ladle, and adjusting the S content in the molten steel to 0.019%;

5) hoisting the molten steel to a continuous casting start ladle, wherein the molten steel comprises 0.06% of C, 0.07% of Si, 0.30% of Mn, 0.019% of P, 0.019% of S and 0.034% of Al;

6) and taking a finished product sample in the tundish to observe the aluminum loss, wherein the finished product sample C is 0.06%, Si is 0.07%, Mn is 0.30%, P is 0.019%, S is 0.019%, and Al is 0.033%, and compared with the ladle sample, the continuous casting aluminum loss is 0.001%.

3. And (3) starting a third furnace, wherein the operation process is as follows:

1) the converter end point component C is 0.03 percent, and the P is 0.013 percent;

2) refining by normal deoxidation and desulfurization and component adjustment operation, wherein the components are adjusted to 0.05 percent of C, 0.06 percent of Si, 0.32 percent of Mn, 0.015 percent of P, 0.002 percent of S and 0.049 percent of Al;

3) feeding a calcium wire for 180 meters into the steel ladle and soft-blowing for 5 min;

4) feeding a sulfur wire of 250 meters into the ladle to adjust the S content in the molten steel to 0.022%;

5) hoisting the molten steel to a continuous casting start ladle, wherein the molten steel comprises 0.05% of C, 0.05% of Si, 0.32% of Mn, 0.015% of P, 0.022% of S and 0.046% of Al in ladle hoisting;

6) and taking a finished product sample in the tundish to observe the aluminum loss, wherein the finished product sample C is 0.05 percent, Si is 0.05 percent, Mn is 0.32 percent, P is 0.015 percent, S is 0.019 percent, Al is 0.043 percent, and compared with the ladle sample, the continuous casting aluminum loss is 0.003 percent.

4. The total of the pouring times is fourteen furnaces, the pouring curve is shown in figure 1, and the position of the stopper rod is stable during pouring, and the liquid level is stable without large fluctuation.

Comparative example:

the method comprises the following specific steps:

1. the first furnace is started to be poured, and the operation process is as follows:

1) the converter end point component C is 0.05 percent, and the P is 0.018 percent;

2) refining is carried out by normal deoxidation and component adjustment (strong desulfurization is not adopted), and the components are adjusted to 0.06 percent of C, 0.06 percent of Si, 0.31 percent of Mn, 0.021 percent of P, 0.006 percent of S and 0.045 percent of Al;

3) sequentially feeding 200 meters of sulfur wire and 240 meters of calcium wire into the steel ladle, and adjusting the S to 0.022%;

4) hoisting the molten steel to a continuous casting start ladle, wherein the molten steel comprises 0.06% of C, 0.06% of Si, 0.31% of Mn, 0.021% of P, 0.022% of S and 0.043% of Al in ladle hoisting;

5) and taking a finished product sample in the tundish to observe the aluminum loss, wherein the finished product sample C is 0.06%, Si is 0.06%, Mn is 0.31%, P is 0.021%, S is 0.022%, Al is 0.035%, and compared with the ladle sample, the continuous casting aluminum loss is 0.008%.

2. And (3) starting a second furnace, wherein the operation process is as follows:

1) the converter end point component C is 0.03 percent, and the P is 0.015 percent;

2) refining is carried out by normal deoxidation and component adjustment (strong desulfurization is not carried out), and the components are adjusted to 0.05% of C, 0.06% of Si, 0.30% of Mn, 0.017% of P, 0.005% of S and 0.046% of Al;

3) sequentially adding 200 meters of sulfur wire and 180 meters of calcium wire into the steel ladle, and adjusting the S to 0.021%;

4) hoisting the molten steel to a continuous casting start ladle, wherein the molten steel comprises 0.05% of C, 0.06% of Si, 0.30% of Mn, 0.017% of P, 0.021% of S and 0.042% of Al in ladle hoisting;

5) and taking a finished product sample in the tundish to observe the aluminum loss, wherein the finished product sample C is 0.05 percent, Si is 0.06 percent, Mn is 0.30 percent, P is 0.021 percent, S is 0.021 percent and Al is 0.040 percent, and compared with the ladle sample, the continuous casting aluminum loss is 0.002 percent.

3. And (3) starting a third furnace, wherein the operation process is as follows:

1) the converter end point component C is 0.04 percent, and the P is 0.015 percent;

2) refining by normal deoxidation and component adjustment (without strong desulfurization), wherein the components are adjusted to 0.05% of C, 0.07% of Si, 0.32% of Mn, 0.017% of P, 0.007% of S and 0.043% of Al;

3) sequentially feeding 200 meters of sulfur wire and 180 meters of calcium wire into the ladle, and adjusting S to 0.023%;

4) hoisting the molten steel to a continuous casting start ladle, wherein the molten steel comprises 0.05% of C, 0.07% of Si, 0.32% of Mn, 0.017% of P, 0.023% of S and 0.040% of Al during ladle hoisting;

5) and taking a finished product sample in the tundish to observe the aluminum loss, wherein the finished product sample C is 0.05 percent, Si is 0.07 percent, Mn is 0.32 percent, P is 0.017 percent, S is 0.023 percent, Al is 0.037 percent, and compared with the ladle sample, the continuous casting aluminum loss is 0.003 percent.

4. The pouring is stopped due to overlarge liquid level fluctuation after the six-furnace production in the pouring time, the pouring curve is shown in figure 2, the fluctuation of the liquid level of the two furnaces before the pouring time is large, the opening degree of the stopper rod is fast increased, and the process stability is poor.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.