Production method for increasing continuous casting furnace number of oriented silicon steel

Abstract

The invention discloses a production method for increasing the number of continuous casting furnaces of oriented silicon steel. The production method comprises the following steps: 1, component range; 2, controlling the temperature of molten steel; 3, the baking effect of the refractory material is ensured; 4, protective casting; 5, equipment precision control; 6, optimizing the insertion depth of the submersed nozzle; seventhly, a crystallizer and primary cooling are conducted; 8, secondary cooling; ninthly, dynamic soft reduction is conducted; 10, the pulling speed is controlled, casting is started at the normal pulling speed of 0.8 m / min to 1.0 m / min and the weight of a tundish is 25 tons, casting is started manually, and a withdrawal and straightening machine is started according to a normal casting program; the pulling speed is set to be 0.4 m / min before casting, and after a new blank is taken out of a crystallizer, the pulling speed is gradually increased to the typical pulling speed of 1.0 m / min. According to the production method for increasing the number of continuous casting furnaces of the oriented silicon steel, the smelting pulling speed of the oriented silicon steel is increased to 1.0 m / min from 0.80 m / min, and the number of continuous casting furnaces is increased to 17 from 11.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of continuous casting production, and particularly relates to a production method for improving continuous casting furnace number of oriented silicon steel. BACKGROUND

[0002] Oriented silicon steel is an important soft magnetic alloy material, which is mainly used as core material in various transformer products and is widely used in the power industry. According to different process characteristics and magnetic properties, the oriented silicon steel is divided into two types of general oriented silicon steel (CGO) and high magnetic oriented silicon steel (Hi-B). The production process characteristics of CGO steel is to use MnS as the inhibitor and the secondary medium reduction cold rolling method. The high magnetic oriented silicon steel (Hi-B) has two different production methods according to the use of inhibitors and manufacturing processes.

[0003] In continuous casting production, since the oriented silicon steel is a traditional "soft steel", it has poor heat conduction ability, and the liquid heat conduction rate is about 27% lower than that of plain carbon steel, and has the characteristics of weak heat conduction, and is easy to deform at high temperature. Therefore, in the continuous casting production, the problems of crystallizer liquid level fluctuation, casting billet bulging and concave defects, center segregation, center porosity and crack internal quality problems of the casting billet are important factors affecting the continuous casting furnace number, and therefore, the reasonable design of the cooling system and the casting speed is an important method to improve the continuous casting furnace number. SUMMARY

[0004] The purpose of the application is to provide a production method for improving the continuous casting furnace number of oriented silicon steel, which increases the oriented silicon steel smelting pulling speed from 0.80 meters per minute to 1.0 meters per minute, and increases the continuous casting furnace number from 11 furnaces to 17 furnaces.

[0005] To solve the above technical problems, the application adopts the following technical scheme:

[0006] The application is a production method for improving the continuous casting furnace number of oriented silicon steel, which comprises the following steps:

[0007] I. Component range

[0008] The mass percentage of the chemical components includes: C 0.05-0.06%, Si 3.20-3.40%, Mn 0.09-0.11%, P 0.020-0.035%, S 0.07-0.011%, Als 0.027-0.030%, N 0.070-0.082%, and the rest is Fe and inevitable impurities;

[0009] II. Molten steel temperature control

[0010] The first tundish liquid steel temperature is 10℃ higher than normal casting, and cold ladle, overhaul ladle and new ladle are prohibited from going online to avoid such accidents. Since the oriented silicon steel has high Si content, its thermal conductivity is lower than that of plain carbon steel, so the solidification speed is also lower. According to the composition of the steel grade, the liquidus temperature is calculated to be 1501℃. Combined with the low solidification speed of oriented silicon steel, low superheat casting can inhibit the growth of columnar crystals and promote the growth of equiaxed crystals. The temperature of the continuous casting tundish is controlled to be 10-25℃;

[0011] III. Ensure the roasting effect of refractory

[0012] The roasting time of the quick-change tundish is increased by 0.5h compared to the normal tundish, and the temperature of the tundish before quick change is ensured to be above 1100℃, the submerged entry nozzle is roasted to above 950℃, and the weight during casting is 60-75t, and the pouring process is stopped for 15-25t;

[0013] IV. Protect the casting

[0014] The argon flow rate of the long nozzle of the ladle is 6-10m 3 / h, and a solid stopper is used;

[0015] V. Control the precision of equipment

[0016] Increase the inspection, measurement and calibration frequency between casting; adjust the inspection equipment state and precision, check the measurement of the mold, the state of the mold thermocouple, avoid the liquid level fluctuation in the production process, the sticking alarm reason unplanned stop pouring, check the ladle rotating table, the sliding nozzle of the ladle, ensure the normal rotation, normal action, realize multi-furnace continuous casting;

[0017] VI. Optimize the insertion depth of submerged entry nozzle

[0018] With the increase of continuous casting furnace number, the original 3 slag lines are increased to 4 slag lines, the distance between slag lines is 20mm, and the tundish car height is 60mm, 40mm, 20mm and 0mm respectively to avoid slag line overlap, which leads to nozzle erosion and fracture;

[0019] VII. Mold and primary cooling

[0020] 1) Mold steel quantity: use right-angle mold, narrow side copper plate ≤50,000 tons, wide side copper plate ≤100,000 tons;

[0021] 2) Primary cooling system: for 1650mm caster pouring, water flow wide side 4800L / min, narrow side 500L / min, require mold water temperature difference ≤10℃, narrow side water flow can be appropriately increased, actual value and set value deviation ≤5%;

[0022] 3) Adjust the lower mouth and taper: mold lower mouth taper coefficient 1.0%, lower mouth shrinkage coefficient 1.00; taper actual value and set value deviation ≤0.3%;

[0023] 4) Mold level: After the mold level stabilizes, the actual level must be measured, and the target level fluctuation is ≤±3 mm;

[0024] 5) Mold vibration parameters: secondary control, silicon steel vibration parameters;

[0025] Eight, secondary cooling

[0026] According to the characteristics of high-magnetic-induction oriented silicon steel, the secondary cooling system adopts a "strong" cooling mode, with a water quantity of 0.7-0.9 L / Kg to 1.8-2.0 L / Kg higher than that of general carbon steel and low-carbon alloy steel. Meanwhile, referring to the design idea of the water table of the first-stage secondary cooling of the 1650 mm caster: water quantity in the middle of the fan-shaped section = 0.5 * water quantity at the edge, the water table of the first-stage secondary cooling of the silicon steel is established. Then, taking the first-stage water table as the original parameter, and based on the target temperature of the casting blank, the dynamic control of the secondary cooling water is finally realized according to the micro-unit heat balance principle; the target temperature of the casting blank

[0027] Cooling water zones Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Zone 6 Zone 7 Zone 8 Zone 9 Zone 10 Zone 11 Target temperature °C 1120 1070 975 950 920 905 892 883 879 850 850

[0028] Nine, dynamic soft reduction

[0029] Due to the poor heat conduction of the oriented silicon steel liquid, the soft reduction interval needs to be moved backward to ensure that it is reduced at the end of solidification. The dynamic soft reduction parameters are shown in the following table:

[0030]

[0031] The dynamic soft reduction is automatically controlled in two stages, and the roll gap deviation is ≤0.3 mm;

[0032] Ten, speed control:

[0033] The normal speed is 0.8 m / min-1.0 m / min, the tundish weight is 25 tons for casting, and the casting is started manually with the normal casting program to start the speed and straightening machine. Before casting, the speed is set to 0.4 m / min, and after the new blank comes out of the mold, the speed is gradually increased to the typical speed of 1.0 m / min.

[0034] Further, the tundish is roasted for 150-155 min during normal casting.

[0035] Further, the tundish temperature is measured to be 1130℃ by lifting the roaster.

[0036] Further, the submerged entry nozzle is roasted to 967℃.

[0037] Further, the argon flow rate of the long nozzle of the 1# ladle is 9 m 3 / h.

[0038] Further, the arc deviation of the measured sector before the first pouring is less than ±0.30mm, and the opening deviation is less than ±0.50mm.

[0039] Further, the light pressing position is the 6th-7th segment, the pressing amount is 3mm, and the roll gap deviation is less than or equal to 0.3mm.

[0040] Compared with the prior art, the beneficial technical effects of the present application are:

[0041] The production practice of improving the continuous casting furnace number of oriented silicon steel is carried out under the above conditions, and good application effects are obtained. The oriented silicon steel is initially smelted at a speed of 0.80 meters per minute, and the continuous casting furnace number is 11. After the above application, the smelting speed of the oriented silicon steel is increased from 0.80 meters per minute to 1.0 meters per minute, and the continuous casting furnace number is increased from 11 to 17.

[0042] Since the present application is adopted, the production capacity of oriented silicon steel is greatly improved, the production frequency and pouring interval of oriented silicon steel per month are reduced, the smelting production capacity of oriented silicon steel is fully released, and the surface and internal quality of the oriented silicon steel are ensured through the implementation of the above measures, and the annual output of the oriented silicon steel is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The production trend chart. DETAILED DESCRIPTION

[0044] A production method for improving the continuous casting furnace number of oriented silicon steel, comprising:

[0045] I. Composition range

[0046] Taking the 1# pouring of the 1650mm double-flow slab continuous casting machine as an example, a total of 17 heats are poured, and the chemical composition of the tundish meets the requirements in the following table.

[0047]

[0048] II. Molten steel temperature control

[0049] 1# pouring plan: BTGQ021250x17 heats, steel grade liquidus temperature: 1501℃, 12# ladle (normal turnover ladle, good bottom blowing), first heat 1# RH steel temperature 1565℃, higher than normal steel temperature by 10℃.

[0050] III. Ensure the baking effect of refractory

[0051] 1# pouring uses 9# tundish, tundish baking time: 17:30-20:35, baking 185min, normal pouring opening tundish baking 150-155min, measure the tundish temperature by lifting the baking device to 1130℃, and the submerged entry nozzle is baked to 967℃.

[0052] Four, protect casting

[0053] 1# Pouring large ladle argon flow 9m3 / h, using solid plug. Ladle water sampling in 140 tons, 80 tons of molten steel ladle sampling, sampling tons less than ± 5 tons.

[0054] Five, equipment precision control

[0055] 1# Pouring before measuring the sector segment arc deviation is less than ± 0.30mm, opening degree deviation is less than ± 0.50mm. Check the measurement of crystallizer centering, crystallizer thermocouple state is normal, before pouring check ladle rotary table, ladle sliding nozzle, rotation is normal, normal action, realize multi-continuous casting.

[0056] Six, immersion nozzle insertion depth optimization

[0057] 1# Pouring plan for 17 furnaces, casting time from 2024 September 20 20 points 42 minutes to 2024 September 21 14 points 55 minutes, a total of 18 hours 13 minutes, slag line as follows:

[0058] Tundish car height 60 mm 40 mm 20 mm 0 mm Time period 20:45-1:05 1:05-5:25 5:25-9:50 9:50-14:55

[0059] Seven, crystallizer and primary cooling

[0060] 1, the amount of steel crystallizer: using right angle crystallizer, narrow side copper plate is less than or equal to 5 million tons, wide side copper plate is less than or equal to 10 million tons.

[0061] 2, the primary cooling system: requires 1650mm caster pouring, water flow wide side 4800L / min, narrow side 500L / min, crystallizer water temperature difference is less than or equal to 10℃.

[0062] 3, 1# Pouring section: 1250mm, adjust the lower mouth and taper: crystallizer lower mouth: 1250mm, taper coefficient 1.0%, set taper: 6.2 taper, actual taper: 6.3mm, actual value and set value deviation is less than or equal to 0.3%.

[0063] 4, the crystallizer liquid level: 1# Pouring crystallizer liquid level after stable, the actual liquid level is 100mm from the crystallizer upper mouth, the actual liquid level is normal, liquid level fluctuation is less than or equal to ± 3mm.

[0064] 5, the crystallizer vibration parameters: two stage control, silicon steel 5# table vibration parameters

[0065] Eight, secondary cooling

[0066] Primary water table

[0067]

[0068]

[0069] Secondary water meter

[0070]

[0071]

[0072] Nine, dynamic soft reduction

[0073] Dynamic soft reduction secondary automatic control, silicon steel dynamic soft reduction is executed, soft reduction position is 6-7 section, reduction amount is 3mm, roll gap deviation is ≤00.3mm.

[0074] Ten, speed control:

[0075] 1# Pouring normal speed 1.0m / min, intermediate package weight 25 tons open pouring, manual open pouring, start to pull the machine with normal open pouring program. Before open pouring, set the speed to 0.4m / min, after the new blank comes out of the crystallizer, gradually increase the speed to typical speed 1.0m / min, and pour normally.

[0076] Production trend chart is shown in Figure 1 .

[0077] Since the adoption of the present application, the oriented silicon steel production capacity has been greatly improved, the oriented silicon steel production frequency and pouring interval per month have been reduced, the smelting capacity of the oriented silicon steel has been fully released. And through the implementation of the above measures, the surface and internal quality of the oriented silicon steel is guaranteed, and the annual output of the oriented silicon steel is effectively improved.

[0078] The above-described embodiments are only preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A production method for increasing the number of continuous casting furnaces for oriented silicon steel, characterized by: Comprise: I. Ingredient range The mass percentage chemical composition includes: C 0.05-0.06%, Si 3.20-3.40%, Mn 0.09-0.11%, P 0.020-0.035%, S 0.07-0.011%, Al 0.027-0.030%, N 0.070-0.082%, the rest is Fe and inevitable impurities; II. Molten steel temperature control The first furnace molten steel temperature in the tundish is 10℃ higher than normal pouring, and cold ladle, overhaul ladle and new ladle are prohibited from going online to avoid such accidents. Since the oriented silicon steel has high Si content, its thermal conductivity is lower than that of plain carbon steel, so the solidification speed is also lower. According to the composition of the steel grade, the liquidus temperature is calculated to be 1501℃. Combined with the low solidification speed of oriented silicon steel, low superheat pouring is used to inhibit the growth of columnar crystals and promote the growth of equiaxed crystals. The temperature of the continuous casting tundish for oriented silicon steel is controlled to 10-25℃; III. Ensure the effect of refractory baking The baking time of the quick-change tundish is increased by 0.5h compared with the normal tundish, ensuring that the temperature of the quick-change tundish before quick change is above 1100℃, the submerged entry nozzle is baked to above 950℃, and the weight during pouring is 60-75t, and the stop pouring is 15-25t; IV. Protection pouring Large package long nozzle argon flow 6-10 m 3 / h, using solid plug rod; V. Equipment precision control Increase the inspection, measurement and calibration frequency between pouring; adjust the inspection equipment state and precision, check the measurement of the mold centering, the mold thermocouple state, avoid liquid level fluctuation during production, sticking alarm causes unplanned stop pouring, check the ladle rotating table, ladle slide nozzle, ensure normal rotation, normal action, realize multi-furnace continuous casting; VI. Optimization of submerged entry nozzle insertion depth With the increase of continuous casting furnace number, the original 3 slag lines are increased to 4 slag lines, the distance between slag lines is 20mm, and the tundish car height is 60mm, 40mm, 20m, 0mm respectively to avoid slag line overlap, leading to water nozzle erosion and fracture; VII. Mold and primary cooling 1) Mold steel quantity: use right-angle mold, narrow side copper plate ≤50,000 tons, wide side copper plate ≤100,000 tons; 2) Primary cooling system: require 1650mm caster pouring, water flow wide side 4800L / min, narrow side 500L / min, require mold water temperature difference ≤10℃, narrow side water flow can be appropriately increased, actual value and set value deviation ≤5%; 3) Adjust the lower mouth and taper: mold lower mouth taper coefficient 1.0%, lower mouth shrinkage coefficient 1.00; taper actual value and set value deviation ≤0.3%; 4) Mold level: after the mold level is stable, the actual level must be measured, target level fluctuation ≤±3mm; 5) Mold vibration parameters: secondary control, silicon steel vibration parameters; VIII. Secondary cooling According to the steel grade characteristics of high magnetic induction oriented silicon steel, the secondary cooling system adopts "strong" cooling mode, and the water quantity is 0.7-0.9L / kg to 1.8-2.0L / Kg higher than that of general carbon steel and low carbon alloy steel. At the same time, referring to the design idea of 1650mm caster primary secondary cooling water table: water quantity in the middle of the sector segment = 0.5*water quantity in the edge, the silicon steel primary secondary cooling water table is established; then taking the primary water table as the original parameter, based on the slab target temperature, according to the micro unit heat balance principle, the dynamic control of secondary cooling water is finally realized; Slab target temperature Nine, dynamic soft reduction Due to the poor heat conduction of oriented silicon steel liquid, the soft reduction interval needs to be moved backward to ensure that it is reduced at the end of solidification. The dynamic soft reduction parameters are shown in the table below: Dynamic soft reduction two-stage automatic control, execute silicon steel dynamic soft reduction, roll gap deviation ≤0.3mm; Ten, speed control: Normal speed 0.8m / min-1.0m / min, intermediate package weight 25 tons, manual pouring, normal pouring program to start the pull straightener; set the speed to 0.4m / min before pouring, and gradually increase the speed to the typical speed of 1.0m / min after the new billet leaves the crystallizer.

2. The production method of increasing the number of continuous casting furnaces for oriented silicon steel according to claim 1, characterized by: Normal pouring opening of the ladle is baked for 150-155min.

3. The production method of increasing the number of continuous casting furnaces for oriented silicon steel according to claim 1, characterized in that: Lift the baking device to measure the temperature of the ladle, which is 1130℃.

4. The production method of increasing the number of continuous casting furnaces for oriented silicon steel according to claim 1, characterized in that: Submerged entry nozzle is baked to 967℃.

5. The production method of increasing the number of continuous casting furnaces for oriented silicon steel according to claim 1, characterized in that: 1# Pouring large package long water argon flow 9m 3 / h.

6. The production method of increasing the number of continuous casting furnaces for oriented silicon steel according to claim 1, characterized in that: The sector segment arc deviation is less than ±0.30mm and the opening deviation is less than ±0.50mm before the 1# pouring.

7. The production method of increasing the number of continuous casting furnaces for oriented silicon steel according to claim 1, characterized in that: Soft reduction position is the 6th-7th segment, reduction amount is 3mm, roll gap deviation ≤0.3mm.

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