Sand adding method for improving self-opening rate of steel ladle

Abstract

The invention relates to the technical field of metallurgical steelmaking, in particular to a sand adding method for improving the self-opening rate of a steel ladle, which comprises the following steps: S1, cleaning the steel ladle, and cleaning and confirming a steel ladle nozzle channel; s2, the steel ladle is moved to a sand adding position, and it is determined that a mechanism is completely opened; s3, adding stuffing sand into a water gap for flow test; s4, after flow testing is completed, the oil cylinder is removed, the retaining pin is closed, sand adding operation is conducted according to the steel ladle age, and it is ensured that the top of the brick cup is in a mushroom shape; s5, after sand adding is completed, the sand adding condition is confirmed; in the step S4, when the steel ladle age is smaller than or equal to 10 times, the first sand adding amount is 20 kg; when the ladle age of the steel ladle is more than 10 times, the first sand adding amount is 25kg; the subsequent supplementing amount is 5kg each time. According to the sand adding method provided by the invention, the self-opening rate of the steel ladle can be ensured to reach 99.9% or above in actual production, and the production stability is favorably maintained.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgical steelmaking, in particular to a sand adding method for improving the self-opening rate of a ladle. Background Art

[0002] The ladle drainage sand needs to be filled in the ladle base brick to isolate the molten steel and the slide plate to protect the slide plate. The drainage sand on the top of the base brick will begin to sinter under the high temperature of the molten steel. When the slide plate is opened, the loose drainage sand at the bottom will automatically flow out, and the sintered layer at the top will also break under the static pressure of the molten steel, causing the molten steel to flow out. This process is called automatic pouring of the ladle. In the actual production process, it is often encountered that the ladle cannot be automatically poured, and steel companies have to use oxygen burning to remedy it to remove the blocked drainage sand. In fact, the oxygen burning process will not only seriously deteriorate the cleanliness of the molten steel, but also pose a safety hazard, and will also affect production efficiency. Therefore, all steel companies attach great importance to improving the automatic pouring rate of the ladle, and take 100% automatic pouring rate as the ultimate goal.

[0003] Many scholars and technicians have studied and analyzed the various factors that affect the automatic pouring rate of the ladle, and obtained three mechanisms why the ladle cannot automatically pour: the sintering layer of the drainage sand is too thick; the molten steel on the drainage sand condenses and the solidification layer formed is too thick; the molten steel penetrates into the drainage sand.

[0004] At present, the domestic method for improving the self-opening rate of the ladle is limited to the control research of a single process parameter, which mainly considers increasing operation, tools or process control. The effect is not good in actual production application. Therefore, it is urgent to combine the production of steel plants to provide a sand adding method to improve the self-opening rate of the ladle. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and to provide a sand adding method for improving the self-opening rate of the ladle. The self-opening rate of the ladle is effectively improved by precise control of the shape and amount of the added sand and effective management of the sand adding process.

[0006] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0007] A sand adding method for improving the self-opening rate of a ladle comprises the following steps:

[0008] S1. Clean the ladle and confirm the cleaning of the ladle water inlet channel;

[0009] S2. Move the ladle to the sand adding position and make sure the mechanism is fully opened;

[0010] S3. Add drainage sand to the water inlet for flow test;

[0011] S4. After the test flow is completed, remove the cylinder closing stop pin and add sand according to the age of the ladle to ensure that the top of the seat brick forms a mushroom shape;

[0012] S5. After the sand adding is completed, the sand adding situation is confirmed;

[0013] In step S4, when the ladle age is ≤10 times, the first amount of sand added is 20 kg; when the ladle age is >10 times, the first amount of sand added is 25 kg; and the subsequent additional amount is 5 kg each time.

[0014] In the sand adding method provided in the present application, cleaning and clearing confirmation are used to effectively prevent foreign matter from falling into the water inlet during the sand adding process, and quantitative sand adding is used to ensure that the drainage sand in the seat brick forms a slightly raised mushroom head shape. The thickness of the sintered layer is ensured to be within the range of 3mm-5mm, which effectively solves the problem of too thick sintered layer and molten steel infiltrating the drainage sand.

[0015] Preferably, in step S2, the mechanism is in a fully open state, that is, the upper water inlet, the upper and lower slide plates, and the lower water inlet of the ladle are in a through state.

[0016] Preferably, in step S1, ladle cleaning comprises the following steps:

[0017] a. Lift the ladle to the ladle turning area to dump the slag, open the ladle cover and carefully observe the ladle lining;

[0018] b. Use an oxygen gun connected to an oxygen blowing pipe to ignite the ladle nozzle. When burning the nozzle, keep the oxygen blowing pipe level with the nozzle hole to avoid burning the slide plate and the upper nozzle. Blow clean the residual steel attached to the nozzle hole and the seat brick hole;

[0019] c. Remove the fire clay residue in the hole of the slide plate, observe whether the clay is extruded evenly, align the center of the slide plate hole, and ensure that the center deviation of the slide plate hole is within 1mm;

[0020] d. After installation, open and close the mechanism twice, clean up the excess fire mud, and make sure that the fire mud is even and the mechanism runs smoothly;

[0021] e. After loading, before standing the ladle, use compressed air to blow away the debris in the nozzle eye;

[0022] f. Before the second slag dumping of the ladle, confirm the situation inside the ladle. Before adding drainage sand to the ladle water inlet, the ladle mechanism is in a fully open state, and the upper water inlet and the slide plate are kept unobstructed. The second slag dumping of the ladle is carried out, and the slag dumping time is greater than 50 seconds.

[0023] Preferably, in step S3, if the flow test is unsuccessful, the remedial measures are as follows:

[0024] If there is a foreign object blocking the channel, push the foreign object out of the channel from the bottom and notify the top to continue the test flow. After the test flow is normal, formal sand addition can be carried out.

[0025] Preferably, in step S4, the sand adding operation is carried out using a quantitative bucket of 5kg, 10kg or 20kg.

[0026] Preferably, the sand adding method further comprises:

[0027] S6. If the interval from the end of sand addition to the time when the ladle receives steel exceeds 60 minutes, the drainage sand needs to be replaced.

[0028] Further preferably, in step S6, the step of replacing the drainage sand is all the steps from step S1 to step S3.

[0029] Preferably, the sand adding method further comprises:

[0030] S7. When replacing the air bricks of the ladle, first replace the air bricks and then add sand.

[0031] Preferably, the drainage sand is chromium drainage sand or zirconium drainage sand; further preferably, when the temperature of the molten steel in the ladle is less than or equal to 1700°C, chromium drainage sand is selected, and when the temperature of the molten steel in the ladle is greater than 1700°C, zirconium drainage sand is selected.

[0032] Preferably, the composition and content of the chromium drainage sand are as follows: Cr2O3≥30%, SiO2≤15%, Al2O3≥10%, MgO≤5%, Fe2O3≥15%, and moisture≤0.2%.

[0033] Cr2O3≥30% increases the melting point of drainage sand to prevent the sintering layer from being too thick, and Al2O3≥10% prevents the penetration of molten steel.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The sand adding method provided by the present invention can effectively improve the self-opening rate of the ladle water inlet. When the ladle mechanism is opened, the early trial flow of the drainage sand is used to solve the factors that affect the self-opening, such as the accumulation of slag in the ladle water inlet and the falling of refractory materials in the upper water inlet of the ladle. At the same time, according to the erosion of the ladle base bricks, the innovative use of a phased addition mode according to the age of the ladle, a quantitative bucket, and a fixed sand adding pipe are adopted to ensure that a suitable sintering layer is formed at the bottom of the drainage sand to avoid the sintering layer being too thick and causing non-self-opening, so as to achieve the use effect of molten steel self-opening.

[0036] 2. It can reduce the consumption of refractory materials, has obvious environmental protection effect and significant economic effect.

[0037] 3. Easy and convenient operation, greatly improving the safety factor and reducing the workload of operators.

[0038] 4. According to the sand adding method provided by the present invention, in actual production, the self-opening rate of the ladle can be guaranteed to reach 99.9% or above, which is conducive to maintaining the stability of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic diagram of the sand adding method provided in Example 1;

[0040] Among them, 1. Pit operator; 2. Sand adding platform; 3. Sand adding pipe; 4. Ladle; 5. Pit; 6. Funnel. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] The present invention provides a sand adding method for improving the self-opening rate of a ladle, comprising the following steps:

[0043] S1. Clean the ladle and confirm the cleaning of the ladle water inlet channel;

[0044] S2. Move the ladle to the sand adding position and make sure the mechanism is fully opened;

[0045] S3. Add drainage sand to the water inlet for flow test;

[0046] After the S4 test flow is completed, remove the cylinder closing stop pin and add sand according to the ladle age to ensure that the top of the seat brick forms a mushroom shape;

[0047] S5. After the sand adding is completed, the sand adding situation is confirmed;

[0048] In step S4, when the ladle age is ≤10 times, the first amount of sand added is 20 kg; when the ladle age is >10 times, the first amount of sand added is 25 kg; and the subsequent additional amount is 5 kg each time.

[0049] In step S2, the mechanism is in a fully open state, that is, the upper water inlet, the upper and lower slide plates, and the lower water inlet of the ladle are in a through state.

[0050] In step S1, ladle cleaning includes the following steps:

[0051] a. Lift the ladle to the ladle turning area and direct the crane to empty the slag from the ladle. Open the ladle cover and carefully observe the condition of the ladle lining;

[0052] b. Use an oxygen gun to connect the oxygen blowing pipe to ignite the ladle nozzle. When burning the eye, the oxygen blowing pipe and the nozzle eye should be kept level to avoid burning the slide plate and the upper nozzle. Blow clean the residual steel attached to the nozzle eye and the seat brick hole;

[0053] c. Remove the fire clay residue in the slide hole, observe whether the clay is extruded evenly, align the center of the slide hole, and ensure that the deviation is within 1mm;

[0054] d. After installation, open and close the mechanism twice, clean up the excess fire mud, and make sure that the fire mud is even and the mechanism runs smoothly;

[0055] e. After loading, before standing the ladle, use compressed air to blow away the debris in the nozzle eye;

[0056] f. Before the second slag dumping of the ladle, confirm the situation inside the ladle. Before adding drainage sand to the ladle water inlet, the ladle mechanism is in a fully open state, and the upper water inlet and the slide plate are kept unobstructed. The second slag dumping of the ladle is carried out, and the slag dumping time is greater than 50 seconds.

[0057] The composition and content of drainage sand are as follows: Cr2O3≥30%, SiO2≤15%, Al2O3≥10%, MgO≤5%, Fe2O3≥15%, moisture≤0.2%.

[0058] In step S3, if the flow test fails, the remedial measures are as follows:

[0059] If there is a foreign object blocking the channel, push the foreign object out of the channel from the bottom and notify the top to continue the test flow. After the test flow is normal, formal sand addition can be carried out.

[0060] In step S4, the sand adding operation is carried out using a quantitative bucket of 5kg, 10kg or 20kg.

[0061] Sand adding methods also include:

[0062] S6. If the interval from the end of sand addition to the ladle receiving steel exceeds 60 minutes, the drainage sand needs to be replaced;

[0063] S7. When replacing the air bricks of the ladle, first replace the air bricks and then add sand.

[0064] In step S6, the step of replacing the drainage sand is the entire step from step S1 to step S3.

[0065] The sand adding method provided by the present invention is used in a trial run of about 30,000 heats per year in a Shandong Iron and Steel Plant, and the comprehensive self-opening rate can reach 99.99%, with basically no interruption, which greatly improves the continuous casting efficiency.

[0066] The materials used in the following examples and comparative examples are all commonly used commercially available materials in the art, and their specific sources are not described in detail here.

[0067] The components and contents of drainage sand are shown in Table 1.

[0068] Table 1 Drainage sand components and contents

[0069] Group <![CDATA[SiO2(%)]]> <![CDATA[Fe2O3(%)]]> <![CDATA[Al2O3(%)]]> <![CDATA[Cr2O3(%)]]> MgO(%) Moisture (%) Drainage sand 1 14.33 21.965 18.5 33.4 2.63 0.12 Drainage sand 2 13.867 20.128 16.49 32.92 2.44 0.08 Drainage sand 3 45.78 14.92 9.52 23.80 2.09 0.17

[0070] In Table 1, drainage sand 1 and drainage sand 2 are chrome drainage sands, and drainage sand 3 is siliceous drainage sand.

[0071] Example 1

[0072] In this embodiment, the ladle age is 98 times, the temperature of the molten steel during turnover is 1650-1578° C., the steel grade is S355J2+N, and the residence time of the molten steel is 160 minutes.

[0073] Based on the above conditions, the schematic diagram of the sand adding method in this embodiment is as follows: Figure 1 As shown, two operators are required, namely, the operator of the sand adding platform 2 and the pit operator 1 in the pit 5 at the bottom of the ladle 4. The sand adding platform 2 is provided with a sand adding pipe 3 extending into the inside of the ladle 4, and a funnel 6 for adding drainage sand is provided at the top of the sand adding pipe 3; the specific steps of adding sand are as follows:

[0074] S1. Ladle cleaning, cleaning and confirmation of the ladle water inlet channel, including the following steps:

[0075] a. Lift the ladle to the ladle turning area and direct the crane to empty the slag from the ladle. Open the ladle cover and carefully observe the condition of the ladle lining;

[0076] b. Use an oxygen gun to connect the oxygen blowing pipe to ignite the ladle nozzle. When burning the eye, the oxygen blowing pipe and the nozzle eye should be kept level to avoid burning the slide plate and the upper nozzle. Blow clean the residual steel attached to the nozzle eye and the seat brick hole;

[0077] c. Remove the fire clay residue in the hole of the slide plate, observe whether the clay is extruded evenly, align the center of the slide plate hole, and ensure that the center deviation of the slide plate hole is within 1mm;

[0078] d. After installation, open and close the mechanism twice, clean up the excess fire mud, and make sure that the fire mud is even and the mechanism runs smoothly;

[0079] e. After loading, before standing the ladle, use compressed air to blow away the debris in the nozzle eye;

[0080] f. Before the second slag dumping of the ladle, confirm the situation inside the ladle. Before adding drainage sand to the ladle water inlet, the ladle mechanism is in a fully open state, and the upper water inlet and the slide plate are kept unobstructed. The second slag dumping of the ladle is carried out, and the slag dumping time is greater than 50 seconds.

[0081] S2. The ladle is moved to the sand adding position, and the mechanism is confirmed to be fully opened. Fully opened means that the upper water inlet, upper and lower slide plates, and lower water inlet of the ladle are in a through state;

[0082] S3. Add drainage sand to the water inlet for test flow, the specific amount of addition is 5kg. When the drainage sand flows out smoothly and the basic circular flow is formed, the test flow is successful;

[0083] If the trial flow is unsuccessful, the remedial measures are as follows:

[0084] If there is a foreign object blocking the channel, push the foreign object out of the channel from the bottom and notify the top to continue the test flow. After the test flow is normal, formal sand addition can be carried out;

[0085] In this embodiment, the drainage sand 1 in Table 1 is selected as the drainage sand.

[0086] S4. After the test flow is completed, close the ladle mechanism, remove the oil cylinder closing stop pin, and add sand according to the age of the ladle to ensure that the top of the seat brick forms a mushroom shape;

[0087] In this embodiment, the ladle age is 98 times, so the initial sand addition amount is determined to be 25 kg, and the subsequent additional addition amount is 5 kg each time, and the sand addition operation is performed using quantitative buckets;

[0088] S5. After the sand addition is completed, the sand addition status is confirmed; in this embodiment, the confirmation process is to take a photo to confirm;

[0089] S6. If the interval from the end of sand addition to the ladle receiving steel exceeds 60 minutes, the drainage sand needs to be replaced;

[0090] S7. When replacing the air bricks of the ladle, first replace the air bricks and then add sand.

[0091] In step S6, the step of replacing the drainage sand is the entire step from step S1 to step S3.

[0092] Example 2

[0093] In this embodiment, the ladle age is 10 times, the temperature of the molten steel turnover process is 1620-1565°C, the steel grade is Q355B, and the molten steel residence time is 130 minutes.

[0094] According to the above conditions, the ladle age in this embodiment is 10 times, so the first sand addition amount is determined to be 15 kg, and the other steps are the same as those in Example 1.

[0095] In this embodiment, the drainage sand 2 in Table 1 is selected as the drainage sand.

[0096] Comparative Example 1

[0097] In this comparative example, the conditions of the ladle and the molten steel are the same as those in Example 1. The specific steps of the sand adding method are different from those in Example 1 in that the drainage sand used is the drainage sand 3 provided in Table 1, and the other steps are the same.

[0098] Using the sand adding method of this comparative example, the self-opening rate of the ladle is 99.8.

[0099] Comparative Example 2

[0100] In this comparative example, the conditions of the ladle and the molten steel are the same as those in Example 2. The specific steps of the sand adding method are different from those in Example 1 in that steps S3 and S5 are not performed and type 3 of drainage sand is used.

[0101] Using the sand adding method of this comparative example, the self-opening rate of the ladle was 99.7%, and when the drainage sand was not completely filled up the water inlet of the steel plate, there was an accident in which the ladle could not be opened and the continuous casting machine was cut off.

[0102] The self-opening rates of the above comparative examples are poor compared with the embodiments for the following reasons: 1. Drainage sand 1 and drainage sand 2 are not used, and the chromium trioxide content in drainage sand 3 is low, and the refractoriness of drainage sand is relatively low. When the molten steel stays in the ladle for a long time, the ladle cannot open by itself due to the excessively thick sintered layer; 2. If S3 is missing, and sand is not added without trial flow, slag and other debris are easily stored in the ladle water inlet, which reduces the fluidity of the drainage sand and causes the ladle water inlet to not open by itself; 3. If step S5 is missing, and it is not confirmed that the drainage sand fills the ladle water inlet to form a certain space to store molten steel, the local refractory material temperature will be high, the sintered layer of drainage sand will be too thick, blocking the water inlet of the molten steel, causing the continuous casting to be interrupted and unable to be poured. Therefore, the better sand adding method is to use drainage sand with relatively optimal cost, no debris in the molten steel water inlet, the sintered layer of drainage sand is normal and controllable, and there are means to monitor the sand adding process steps.

Claims

1. A sand adding method for improving the self-opening rate of a ladle, characterized in that: The steps include: S1. Clean the ladle and confirm the cleaning of the ladle water inlet channel; S2. Move the ladle to the sand adding position and make sure the mechanism is fully opened; S3. Add drainage sand to the water inlet for flow test; S4. After the test flow is completed, remove the cylinder closing stop pin and add sand according to the age of the ladle to ensure that the top of the seat brick forms a mushroom shape; S5. After the sand adding is completed, confirm the sand adding situation; In step S4, when the ladle age is ≤10 times, the first amount of sand added is 20 kg; when the ladle age is >10 times, the first amount of sand added is 25 kg; and the subsequent additional amount is 5 kg each time.

2. The sand adding method according to claim 1, characterized in that: In step S2, the mechanism is in a fully open state, that is, the upper water inlet, the upper and lower slide plates, and the lower water inlet of the ladle are in a through state.

3. The sand adding method according to claim 1, characterized in that: In step S1, ladle cleaning includes the following steps: a. Lift the ladle to the ladle turning area to dump the slag, open the ladle cover and carefully observe the ladle lining; b. Use an oxygen gun connected to an oxygen blowing pipe to ignite the ladle nozzle. When burning the nozzle, keep the oxygen blowing pipe level with the nozzle hole to avoid burning the slide plate and the upper nozzle. Blow clean the residual steel attached to the nozzle hole and the seat brick hole; c. Remove the fire clay residue in the hole of the slide plate, observe whether the clay is extruded evenly, align the center of the slide plate hole, and ensure that the center deviation of the slide plate hole is within 1mm; d. After installation, open and close the mechanism twice, clean up the excess fire mud, and make sure that the fire mud is even and the mechanism runs smoothly; e. After loading, before standing the ladle, use compressed air to blow away the debris in the nozzle eye; f. Before the second slag dumping of the ladle, confirm the situation inside the ladle. Before adding drainage sand to the ladle water inlet, the ladle mechanism is in a fully open state, and the upper water inlet and the slide plate are kept unobstructed. The second slag dumping of the ladle is carried out, and the slag dumping time is greater than 50 seconds.

4. The sand adding method according to claim 1, characterized in that: In step S3, if the flow test fails, the remedial measures are as follows: If there is a foreign object blocking the channel, push the foreign object out of the channel from the bottom and notify the top to continue the test flow. After the test flow is normal, formal sand addition can be carried out.

5. The sand adding method according to claim 1, characterized in that: In step S4, the sand adding operation is carried out using a quantitative bucket of 5kg, 10kg or 20kg.

6. The sand adding method according to claim 1, characterized in that: Sand adding methods also include: S6. If the interval from the end of sand addition to the time when the ladle receives steel exceeds 60 minutes, the drainage sand needs to be replaced.

7. The sand adding method according to claim 6, characterized in that: In step S6, the step of replacing the drainage sand is the entire step from step S1 to step S3.

8. The sand adding method according to claim 6, characterized in that: Sand adding methods also include: S7. When replacing the air bricks of the ladle, first replace the air bricks and then add sand.

9. The sand adding method according to claim 1, characterized in that: The drainage sand is selected from chromium drainage sand or zirconium drainage sand; further preferably, when the temperature of the molten steel in the ladle is less than or equal to 1700°C, chromium drainage sand is selected, and when the temperature of the molten steel in the ladle is greater than 1700°C, zirconium drainage sand is selected.

10. The sand adding method according to claim 1, characterized in that: The composition and content of chromium drainage sand are as follows: Cr2O3≥30%, SiO2≤15%, Al2O3≥10%, MgO≤5%, Fe2O3≥15%, moisture≤0.2%.

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