A method for preparing an induction furnace lining

Abstract

The invention discloses a method for preparing an induction furnace lining, which belongs to the technical field of induction furnaces, and comprises the following steps: step S1: preparing a lining material; step S2: using a steel plate to make a crucible mold adapted to the size of the induction furnace; step S3: laying a layer of refractory aggregate on the furnace bottom as a bottom layer, laying the lining material prepared in step S1 on the refractory aggregate as the furnace bottom; step S4: placing the crucible mold in step S2 on the furnace bottom of the furnace, so that an annular cavity is formed between the crucible mold and the inner wall of the furnace, and the lining material prepared in step S1 is added into the annular cavity along the outer wall of the crucible mold in layers; step S5: starting the induction furnace for preheating; after the preheating is completed, medium-temperature sintering is performed; after the medium-temperature sintering is completed, high-temperature sintering is performed; after the high-temperature sintering is completed, final-temperature sintering is performed, the crucible mold is melted and forms a hard sintering layer with the lining material, and finally a furnace lining is formed. The invention can effectively extend the service life of the furnace lining.

Description

Technical Field

[0001] The invention belongs to the technical field of induction furnaces, and in particular relates to a method for preparing an induction furnace lining. Background Art

[0002] As an efficient melting equipment, induction furnace has been widely used in the field of steel and metal smelting. Its notable features include high steel recovery rate, which can effectively reduce the waste of raw materials and improve production efficiency. At the same time, the intermittent operation capacity of induction furnace enables it to be flexibly adjusted according to production needs to meet the melting needs under different working conditions.

[0003] The core component of an induction furnace is the furnace lining, which is the part that holds high-temperature molten steel. It is usually made of refractory materials and sintered. In actual use, the furnace lining generally faces the problem of short service life, which limits the full performance of the induction furnace. Especially for large induction furnaces, the cycle of dismantling and building the furnace is long, so the service life of the furnace lining directly affects the utilization rate and normal production of the equipment. Once the furnace lining is damaged, it will not only lead to production interruption, increase maintenance and replacement costs, but also may have an adverse effect on the quality of the smelted products.

[0004] Therefore, a method for preparing an induction furnace lining which can extend the service life of the lining is now needed. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing an induction furnace lining, which can effectively extend the service life of the lining, reduce production interruptions caused by lining problems, and improve production efficiency.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing an induction furnace lining comprises the following steps: Step S1: preparing a furnace lining material, the furnace lining material includes corundum and magnesia, and its chemical composition is as follows: Al2O3≥85%, MgO≥10%, water≤0.5%; Step S2: according to the size of the induction furnace, a crucible mold adapted to the induction furnace is made of steel plate, and cross-shaped reinforcing ribs are respectively welded at the upper and lower ends of the inner wall of the crucible mold, so that each end of the cross-shaped reinforcing rib abuts against the inner wall of the crucible mold; the thickness of the crucible mold is 10-20 mm; Step S3: laying a layer of refractory aggregate on the furnace bottom as a bottom layer, laying the furnace lining material prepared in step S1 on the refractory aggregate as the furnace bottom, using a hammer to hit the material to make it settle evenly and exhaust the air; the refractory aggregate is alumina; Step S4: placing the crucible mold in step S2 on the bottom of the furnace to form an annular cavity between the crucible mold and the inner wall of the furnace, adding the furnace lining material prepared in step S1 into the annular cavity along the outer wall of the crucible mold in layers, with each layer having a height of 50-100 mm, and using a tamping tool to move along the circumference of the annular cavity to form a furnace lining; Step S5: start the induction furnace for preheating, the preheating temperature is controlled at 100-200°C, and the duration is 2-4 hours; after the preheating is completed, medium-temperature sintering is carried out, the sintering temperature is controlled at 600-800°C, and the duration is 4-6 hours, and the furnace lining begins to solidify; after the medium-temperature sintering is completed, high-temperature sintering is carried out, the sintering temperature is controlled at 1000-1200°C, and the duration is 6-8 hours; after the high-temperature sintering is completed, final temperature sintering is carried out, the sintering temperature is controlled at 1650-1700°C, and the duration is 3-5 hours, the crucible mold is melted and forms a hard sintered layer with the furnace lining material, and finally the furnace lining is formed.

[0007] A further improvement of the technical solution of the present invention is that in step S2, the crucible mold is a cylindrical structure with a diameter gradually decreasing from top to bottom, and the thickness of the annular cavity between the crucible mold and the inner wall of the furnace chamber gradually increases from top to bottom.

[0008] A further improvement of the technical solution of the present invention is that the angle α between the side wall at the upper end of the crucible mold and the horizontal direction is 75°-85°, and the angle β between the side wall at the lower end and the horizontal direction is 88°-90°.

[0009] A further improvement of the technical solution of the present invention is that a plurality of exhaust holes are evenly spaced along the circumference of the side wall of the crucible mold.

[0010] A further improvement of the technical solution of the present invention is that in step S5, the thickness of the furnace lining formed is 200-400 mm.

[0011] Due to the adoption of the above technical solution, the technical progress achieved by the present invention is: The method for preparing the induction furnace lining of the present invention can effectively extend the service life of the lining, reduce production interruptions caused by lining problems, and improve production efficiency.

[0012] The corundum contained in the furnace lining material of the present invention has a high melting point, a small thermal expansion coefficient, good hot volume stability, and excellent corrosion resistance. During high-temperature use, the corundum reacts in situ with magnesia to generate magnesia-alumina spinel, resulting in volume expansion, thereby effectively inhibiting the cracking of the furnace lining. By using corundum-magnesia ramming material as the furnace lining material, the cracking of the hot surface of the furnace lining is significantly controlled and the cracks are significantly reduced.

[0013] The invention strengthens the structural strength of the crucible mold by welding cross-shaped reinforcing ribs on the inner wall of the crucible mold, thereby effectively preventing the crucible mold from deforming during the furnace building process.

[0014] The invention adopts a gradually reduced diameter design of the crucible mold so that the thickness of the furnace lining gradually increases from top to bottom, thereby effectively increasing the service life of the furnace lining.

[0015] The present invention provides a plurality of exhaust holes on the side wall of the crucible mold, which helps to exhaust air when filling the furnace lining material, ensures that the furnace lining material is more dense, and improves the overall performance of the furnace lining. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a crucible mold in the method for preparing an induction furnace lining of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with embodiments: The present invention provides a method for preparing an induction furnace lining, comprising the following steps: Step S1: prepare furnace lining materials, which include corundum and magnesia, and have the following chemical composition: Al2O3≥85%, MgO≥10%, water≤0.5%, and the following physical properties: bulk density≥2.5g / cm 3 , Linear change rate: 0-1%, compressive strength ≥12MPa, among which, corundum has a high melting point, a small thermal expansion coefficient, good thermal volume stability, and excellent corrosion resistance. During high-temperature use, corundum reacts with magnesia in situ to form magnesia-alumina spinel, resulting in volume expansion, which can effectively inhibit the cracking of the furnace lining. Using corundum-magnesia ramming material as the furnace lining material, the cracking of the hot surface of the furnace lining is significantly controlled and the cracks are significantly reduced; Step S2: according to the size of the furnace of the induction furnace, a crucible mold adapted to the induction furnace is made of steel plates, and cross-shaped reinforcing ribs are welded at the upper and lower ends of the inner wall of the crucible mold through 100 angle steels, so that each end of the cross-shaped reinforcing rib abuts against the inner wall of the crucible mold, thereby enhancing the structural strength of the crucible mold and preventing it from deforming during the furnace building process, wherein "the upper and lower ends of the inner wall of the crucible mold" refers to the upper and lower parts of the inner wall of the crucible mold, and does not specifically refer to the upper and lower ends of the inner wall of the crucible mold; like Figure 1 As shown, the thickness of the crucible mold is 10-20 mm, and the crucible mold is a cylindrical structure with a gradually reduced diameter from top to bottom. Therefore, the thickness of the annular cavity between the crucible mold and the inner wall of the furnace chamber gradually increases from top to bottom, so that the thickness of the furnace lining gradually increases from top to bottom, effectively increasing the service life of the furnace lining. Preferably, the angle α between the side wall at the upper port of the crucible mold and the horizontal direction is 75°-85°, and the angle β between the side wall at the lower port and the horizontal direction is 88°-90°; In order to make the filling of the furnace lining material more dense and improve the overall performance of the furnace lining, the crucible mold is evenly spaced along the circumference of its side wall with a number of exhaust holes. The spacing between each row of exhaust holes is 300mm, and the spacing between two adjacent exhaust holes is 300mm. The positions of the exhaust holes are staggered. Step S3: laying a layer of refractory aggregate on the furnace bottom as a bottom layer, laying the furnace lining material prepared in step S1 on the refractory aggregate as the furnace bottom, using a hammer to hit the material to make it settle evenly and exhaust the air, thereby helping to improve the thermal insulation and durability of the furnace bottom, wherein the refractory aggregate is alumina; Step S4: placing the crucible mold in step S2 on the furnace bottom of the furnace to form an annular cavity between the crucible mold and the inner wall of the furnace, adding the furnace lining material prepared in step S1 into the annular cavity along the outer wall of the crucible mold in layers, with each layer having a height of 50-100 mm, and using a tamping tool to move along the circumference of the annular cavity to tamp and form a furnace lining, thereby ensuring the uniformity and density of the furnace lining material; Step S5: start the induction furnace for preheating, the preheating temperature is controlled at 100-200°C, and the duration is 2-4 hours; after the preheating is completed, medium-temperature sintering is carried out, the sintering temperature is controlled at 600-800°C, and the duration is 4-6 hours, and the furnace lining begins to solidify; after the medium-temperature sintering is completed, high-temperature sintering is carried out, the sintering temperature is controlled at 1000-1200°C, and the duration is 6-8 hours; after the high-temperature sintering is completed, final temperature sintering is carried out, the sintering temperature is controlled at 1650-1700°C, and the duration is 3-5 hours, the crucible mold is melted and forms a hard sintered layer with the furnace lining material, and finally forms a furnace lining, that is, after the crucible mold is melted, it forms a hard sintered layer with the furnace lining material, and finally forms a furnace lining. Preferably, the thickness of the formed furnace lining is 200-400mm.

[0018] The method for preparing the induction furnace lining of the present invention can effectively extend the service life of the lining, reduce production interruptions caused by lining problems, and improve production efficiency.

[0019] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for preparing an induction furnace lining, characterized in that The following steps are involved: Step S1: preparing a furnace lining material, the furnace lining material includes corundum and magnesia, and its chemical composition is as follows: Al2O3≥85%, MgO≥10%, water≤0.5%; Step S2: according to the size of the induction furnace, a crucible mold adapted to the induction furnace is made of steel plate, and cross-shaped reinforcing ribs are respectively welded at the upper and lower ends of the inner wall of the crucible mold, so that each end of the cross-shaped reinforcing rib abuts against the inner wall of the crucible mold; the thickness of the crucible mold is 10-20 mm; Step S3: laying a layer of refractory aggregate on the furnace bottom as a bottom layer, laying the furnace lining material prepared in step S1 on the refractory aggregate as the furnace bottom, and using a hammer to hit the material to make it settle evenly and exhaust the air; the refractory aggregate is alumina; Step S4: placing the crucible mold in step S2 on the bottom of the furnace to form an annular cavity between the crucible mold and the inner wall of the furnace, adding the furnace lining material prepared in step S1 into the annular cavity along the outer wall of the crucible mold in layers, with each layer having a height of 50-100 mm, and using a tamping tool to move along the circumference of the annular cavity to form a furnace lining; Step S5: start the induction furnace for preheating, the preheating temperature is controlled at 100-200°C, and the duration is 2-4 hours; after the preheating is completed, medium-temperature sintering is performed, the sintering temperature is controlled at 600-800°C, and the duration is 4-6 hours, and the furnace lining begins to solidify; after the medium-temperature sintering is completed, high-temperature sintering is performed, the sintering temperature is controlled at 1000-1200°C, and the duration is 6-8 hours; After high-temperature sintering is completed, final temperature sintering is carried out. The sintering temperature is controlled at 1650-1700℃ and lasts for 3-5 hours. The crucible mold melts and forms a hard sintering layer with the furnace lining material, finally forming the furnace lining.

2. The method for preparing an induction furnace lining according to claim 1, characterized in that: In step S2, the crucible mold is a cylindrical structure with a diameter gradually decreasing from top to bottom, and the thickness of the annular cavity between the crucible mold and the inner wall of the furnace chamber gradually increases from top to bottom.

3. The method for preparing an induction furnace lining according to claim 2, characterized in that: The angle α between the side wall at the upper port of the crucible mold and the horizontal direction is 75°-85°, and the angle β between the side wall at the lower port and the horizontal direction is 88°-90°.

4. The method for preparing an induction furnace lining according to claim 3, characterized in that: The crucible mold is provided with a plurality of exhaust holes evenly spaced along the circumference of the side wall thereof.

5. The method for preparing an induction furnace lining according to claim 1, characterized in that: In step S5, the thickness of the formed furnace lining is 200-400 mm.

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