A method for improving the recovery of a calcium line

Abstract

This invention discloses a method for improving the yield of calcium wire rod, comprising: S1: measuring the current temperature of the molten steel and calculating the superheat, denoted as ΔT; S2: calculating the calcium wire feeding speed V, the formula for calculating speed V is as follows: V = 6.6 - 0.195 * ΔT + 0.0011 * ΔT 2 V is in m / s; △T is in °C; S3: Calculate the calcium wire length L based on the molten steel mass m; S4: Feed the calcium wire at a feeding speed V, with the feeding device set to a speed of V*60, i.e., a feeding speed per minute; S5: Soft blowing argon gas; The beneficial effects of this invention are: it determines the feeding speed of molten steel in different ladles, solves the problem of calcium wire vaporization and dispersion into the air caused by premature melting of the added calcium wire, and the problem of erosion of the ladle bottom caused by slow melting, improves the calcium wire yield, directly affects the castability of molten steel, is beneficial to subsequent continuous casting production, and controls the consumption of calcium wire, reducing production costs.

Description

Technical Field

[0001] This invention belongs to the field of steel refining in iron and steel metallurgy, specifically a method for improving the yield of calcium wire. Background Technology

[0002] In the continuous casting process, the primary issue to be addressed is the castability of molten steel. The castability of molten steel depends on its cleanliness, meaning that the inclusions in the molten steel must be easily absorbed by the top slag, be few in number, and free of large inclusions. For hot-rolled specialty steels, to improve the castability of molten steel, calcium wire is often fed into the molten steel during the refining process to achieve the purpose of removing inclusions by modifying them.

[0003] In the refining process, when calcium wire is fed into the molten steel, it is necessary to ensure that the calcium wire does not melt too early. If the calcium wire melts too early, it will easily vaporize and escape into the air because calcium has a low boiling point while the temperature of molten steel is high. Similarly, the calcium wire should not melt too late, as this will cause corrosion to the bottom of the ladle and also affect the overall production rhythm.

[0004] In the current production process, parameters such as wire feeding speed, calcium wire diameter, and molten steel superheat are mostly determined based on production rhythm and experience. The wire feeding speed is usually fixed at 100m / min to 150m / min. However, when facing multiple production tasks, the temperature of molten steel in different batches and ladles is not a constant value. Determining a uniform and fixed wire feeding speed based solely on production experience can easily lead to problems such as calcium wire melting too early or too slowly, resulting in low yield, large calcium wire consumption, and increased costs.

[0005] The calcium wire yield directly leads to inconsistent deformation of inclusions in the steel, resulting in fluctuations in the castability of the molten steel and seriously affecting the stable operation of continuous casting. Summary of the Invention

[0006] The purpose of this invention is to provide a method for improving the yield of calcium wire, so as to solve at least one of the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides a method for improving the yield of calcium wire, comprising the following steps:

[0008] S1: Measure the current superheat of molten steel, calculate the superheat, and record the superheat as ΔT;

[0009] S2: Solve for the calcium feeding velocity V. The formula for calculating the velocity V is as follows:

[0010] V=6.6-0.195*△T+0.0011*△T 2 ;

[0011] The unit of V is m / s;

[0012] The unit of △T is ℃;

[0013] S3: Select the length L of the calcium wire based on the mass m of the molten steel;

[0014] S4: Feed the calcium wire at the speed V set on the wire feeding device to V*60, which is the wire feeding speed per minute;

[0015] S5: Soft blowing argon gas.

[0016] Furthermore: the difference between the current measured temperature of the molten steel and the liquidus temperature of the corresponding steel grade is calculated using the following formula:

[0017]

[0018] Where T is the current measured temperature of the molten steel; the unit of T is °C.

[0019] This refers to the liquidus temperature of the steel grade corresponding to the molten steel. The unit is ℃.

[0020] Furthermore, the selection rules for the calcium wire length L are as follows:

[0021]

[0022] In the formula: L is the selected length of the calcium wire, in meters;

[0023] A represents the preset calcium content in the molten steel, in ppm.

[0024] B represents the preset yield of calcium line;

[0025] m represents the mass of molten steel, in tons;

[0026] X represents the mass of calcium contained in each meter of calcium wire, expressed in g / m.

[0027] Furthermore, the value of A ranges from 10ppm to 12ppm.

[0028] Furthermore, the value of B ranges from 20% to 22%.

[0029] Furthermore, the soft blowing of argon gas lasts for 10 to 20 minutes.

[0030] Furthermore: the soft-blown argon gas has a flow rate controlled at 4m³ / h. 3 / min~6m 3 / min.

[0031] Furthermore: the mass of calcium X contained in each meter of calcium wire, where X ranges from 50 g / m to 60 g / m.

[0032] The design principle of the numerical calculation formula for V in this invention is as follows:

[0033] Under different wire feeding rates and superheat degrees, the convective heat transfer between calcium wire and molten steel varies, which affects the melting of calcium wire. Therefore, the melting of calcium wire in multiple groups of molten steel production was observed, and the variables at the same melting state were recorded: calcium wire feeding rate V and superheat degree ΔT. At the same time, a linear regression equation was established: V=a1+a2*ΔT+a3*ΔT 2 By fitting the data, we obtained the following values: a1 = 6.6, a2 = -0.195, a3 = 0.0011.

[0034] The beneficial effects of this invention are as follows:

[0035] 1. Determine the wire feeding speed for molten steel in different ladles and adapt different wire feeding speeds for different molten steels; thereby solving the problems of calcium wire vaporization and escape into the air caused by premature melting and the erosion of the ladle bottom caused by slow melting.

[0036] 2. It improves the calcium wire yield, which directly enhances the castability of molten steel and facilitates subsequent continuous casting production.

[0037] 3. By controlling the consumption of calcium wire, production costs have been reduced. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention and the prior art, the drawings used in the description of the embodiments and the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart illustrating a specific implementation of the present invention. Detailed Implementation

[0040] The specific embodiments of the present invention are described in detail below. The flow of these embodiments is illustrated in the accompanying drawings, wherein the same reference numerals denote the same parameters throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0041] Furthermore, in the following detailed description, numerous specific details are set forth for ease of explanation in order to provide a full understanding of the embodiments disclosed herein; however, it will be apparent that one or more embodiments may be practiced without these specific details.

[0042] Figure 1This is a flowchart illustrating the implementation of a method to improve the yield of calcium filament.

[0043] like Figure 1 As shown, this embodiment is a method for improving the yield of calcium filaments, which consists of the following steps:

[0044] S1: Measure the current superheat of molten steel, calculate the superheat, and record the superheat as ΔT;

[0045] S2: Solve for the calcium feeding velocity V. The formula for calculating the velocity V is as follows:

[0046] V=6.6-0.195*△T+0.0011*△T 2 ;

[0047] S3: Based on the molten steel quality m, the preset calcium content in the molten steel A, the preset calcium wire yield B, and the calcium content per meter of wire...

[0048] The calcium content X determines the length L of the calcium line;

[0049] S4: Feed the calcium wire at a speed V, with the feeding device set to V*60, i.e., a feeding speed per minute.

[0050] Line feeding;

[0051] S5: Soft blowing argon gas;

[0052] Furthermore: Superheat is the difference between the current temperature of the molten steel and the liquidus line of the corresponding steel grade, and the specific formula is as follows:

[0053]

[0054] Where T is the current measured temperature of the molten steel;

[0055] This refers to the liquidus temperature of the steel grade corresponding to the molten steel.

[0056] Furthermore, the selection rules for the calcium line length L are as follows:

[0057] Given that the calcium content in the molten steel is preset to A, the preset calcium wire yield is B, and the mass of calcium in each meter of calcium wire is X, the formula for selecting the length L of the calcium wire is:

[0058]

[0059] In the formula: L is the length of the calcium line, in meters;

[0060] A represents the preset calcium content in the molten steel, in ppm.

[0061] B represents the preset yield of calcium line;

[0062] m represents the mass of molten steel, in tons;

[0063] X represents the mass of calcium contained in each meter of calcium wire, expressed in g / m.

[0064] Furthermore, considering the pourability of molten steel, the value range of A is set to 10ppm to 12ppm.

[0065] Furthermore: argon gas is gently blown in, with a specific blowing time of 10 to 20 minutes.

[0066] Furthermore: argon gas is gently blown in, with the specific argon gas flow rate controlled at 4 m³ / s. 3 / min~6m 3 / min.

[0067] The present invention will be further illustrated below with reference to the embodiments. The embodiments are only used to illustrate the present invention and are not intended to limit the present invention in any way.

[0068] Specific embodiment 1 of the present invention, taking the production of pipeline steel X60M as an example, is shown in the table below:

[0069] The specific steps are as follows:

[0070]

[0071] S1: The temperature of molten steel in the ladle is 1556℃, the liquidus temperature of the steel grade is 1521℃, and the superheat ΔT = 35℃;

[0072] S2: Solve for the linear velocity V of calcium feeding:

[0073] V = 6.6 - 0.195 * 35 + 0.0011 * 35 2 =1.12 m / s;

[0074] S3: Molten steel mass m = 210t, calcium wire is selected, the preset calcium content in the molten steel A = 10ppm, the preset calcium wire yield B = 20%, and the mass of calcium in each meter of calcium wire X = 55g / m. Then the length L of the calcium wire is:

[0075]

[0076] That is, the length of the calcium wire is selected as 191m;

[0077] S4: Set the wire feeding speed of the wire feeding device to V*60, i.e., 67m / min, and start feeding the wire;

[0078] S5: After wire feeding, gently blow argon gas for 10 minutes, controlling the argon gas flow rate at 6m³ / min. 3 / min.

[0079] Sampling and testing revealed that the Ca (calcium) content in the molten steel was 12 ppm, and the calcium recovery rate was 30.5%.

[0080] Specific embodiment 2 of the present invention, taking the production of pipeline steel X60M as an example, is shown in the table below:

[0081]

[0082] The specific steps are as follows:

[0083] S1: The temperature of molten steel in the ladle is 1541℃, the liquidus temperature of the steel grade is 1521℃, and the superheat ΔT = 20℃;

[0084] S2: Solve for the linear velocity V of calcium feeding:

[0085] V = 6.6 - 0.195 * 20 + 0.0011 * 20 2 =3.14 m / s;

[0086] S3: Molten steel mass m = 210t, preset calcium content in molten steel A = 10ppm, preset calcium wire yield B = 20%, calcium wire selected, mass of calcium in each meter of calcium wire X = 55g / m, then the length L of the calcium wire is:

[0087]

[0088] That is, the length of the calcium wire is selected as 191m;

[0089] S4: Set the wire feeding speed of the wire feeding device to V*60, i.e., 188m / min, and start feeding the wire;

[0090] S5: After wire feeding, gently blow argon gas for 10 minutes, controlling the argon gas flow rate at 6m³ / min. 3 / min.

[0091] Sampling and testing revealed that the Ca (calcium) content in the molten steel was 11 ppm, and the calcium recovery rate was 28.0%.

[0092] Comparative Example 3 to Specific Example 1 of the present invention, taking the production of pipeline steel X60M as an example, is shown in the table below:

[0093]

[0094] The specific steps are as follows:

[0095] S1: The temperature of the molten steel in the ladle is 1556℃, and the liquidus temperature of the steel grade is 1521℃;

[0096] S2: The wire feeding speed of the device is set to a fixed value of 150m / min;

[0097] S3: 210t of molten steel, using calcium wire, with a calcium content of X = 55g / m per meter of calcium wire, and a length of 191m;

[0098] S4: Set the wire feeding speed of the wire feeding device to a fixed value of 150m / min, and start feeding the wire;

[0099] S5: After wire feeding, gently blow argon gas for 10 minutes, controlling the argon gas flow rate at 6m³ / min. 3 / min.

[0100] Sampling and testing revealed that the Ca (calcium) content in the molten steel was 6 ppm, and the calcium recovery rate was 15.3%.

[0101] Comparative Example 4 to Specific Example 2 of the present invention, taking the production of pipeline steel X60M as an example, is shown in the table below:

[0102]

[0103] The specific steps are as follows:

[0104] S1: The temperature of molten steel in the ladle is 1541℃, and the liquidus temperature of the steel grade is 1521℃;

[0105] S2: The wire feeding speed of the device is set to a fixed value of 150m / min;

[0106] S3: 210t of molten steel, calcium wire is selected, the mass of calcium in each meter of calcium wire is X=55g / m, and the length of calcium wire is 191m;

[0107] S4: Set the wire feeding speed of the wire feeding device to a fixed value of 150m / min, and start feeding the wire;

[0108] S5: After wire feeding, gently blow argon gas for 10 minutes, controlling the argon gas flow rate at 6m³ / min. 3 / min.

[0109] Sampling and testing revealed that the Ca (calcium) content in the molten steel was 8 ppm, and the calcium linear recovery rate was 20.4%.

[0110] The foregoing has provided a very detailed description of one or more embodiments of the present invention. However, the description is merely a specific example of the present invention and should not be considered as limiting the scope of application of the present invention. All other methods and modifications proposed based on the content of this invention should fall within the scope of patent protection of this invention.

Claims

1. A method for improving the yield of calcium wire, characterized in that, Includes the following steps: S1: Measure the current temperature of the molten steel and calculate the superheat, which is denoted as ΔT; S2: Solve for the calcium feeding velocity V. The formula for calculating the velocity V is as follows: V=6.6-0.195*△T+0.0011*△T 2 ; The unit of V is m / s; The unit of △T is ℃; S3: Calculate the length L of the calcium wire based on the mass m of the molten steel; S4: Feed the calcium wire at the set speed V of the wire feeding device, which is V*60, i.e., the wire feeding speed per minute; S5: Soft blowing argon gas.

2. The method for improving calcium wire yield according to claim 1, characterized in that, The superheat is the difference between the current measured temperature of the molten steel and the liquidus temperature of the corresponding steel grade. The specific formula is as follows: Where T is the current measured temperature of the molten steel; the unit of T is °C. This refers to the liquidus temperature of the steel grade corresponding to the molten steel. The unit is ℃.

3. The method for improving calcium wire yield according to claim 1, characterized in that, The selection rules for the calcium wire length L are as follows: In the formula: L is the length of the calcium line, in meters; A represents the preset calcium content in the molten steel, in ppm. B represents the preset yield of calcium line; m represents the mass of molten steel, in tons; X represents the mass of calcium contained in each meter of calcium wire, expressed in g / m.

4. The method for improving calcium wire yield according to claim 3, characterized in that, The value of A ranges from 10ppm to 12ppm.

5. The method for improving calcium wire yield according to claim 3, characterized in that, The value of B ranges from 20% to 22%.

6. The method for improving calcium wire yield according to claim 1, characterized in that, The argon gas is blown softly for 10 to 20 minutes.

7. The method for improving calcium wire yield according to claim 6, characterized in that, The soft-blown argon gas has a flow rate controlled at 4 m³ / h. 3 / min~6m 3 / min.

8. The method for improving calcium wire yield according to claim 3, characterized in that, The mass of calcium X contained in each meter of calcium wire is in the range of 50 g / m to 60 g / m.

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