Base sheet for air brick production

Abstract

The utility model discloses a kind of substrates for air brick production, including substrate body, the substrate body is polyester substrate, and at least one end surface of substrate body is rough end surface.The surface of substrate body is treated to become rough surface, compared with the substrate surface of conventional use, increase the surface roughness, after the air brick is formed when, the substrate is embedded in air brick, the gap both sides formed by the substrate sintering loss in high-temperature sintering process become rough, the specific surface area of slit both sides becomes large, molten steel wetting side needs higher wetting surface energy, so reduce the flow speed of molten steel in the process of steel penetration, thereby reduce the amount of steel penetration.

Description

Technical Field

[0001] This utility model belongs to the technical field of steel ladle bottom-blown permeable brick manufacturing, specifically relating to a substrate used in the production of permeable bricks. Background Technology

[0002] Argon blowing in a ladle is an important method of ladle refining, which can unify the temperature and composition of molten steel and promote the flotation of inclusions. The core of ladle argon blowing is the permeable brick. During use, the permeable brick of the ladle must have a wide range of adjustable gas volume, high blowing rate, erosion resistance, corrosion resistance, and a service life that is synchronized with that of the bottom brick of the ladle.

[0003] Currently, the main structural types of permeable bricks include dispersed permeable bricks, through-hole permeable bricks, and slotted permeable bricks. With the development of metallurgical production technology and the continuous improvement of product variety and quality requirements, the demands on ladle permeable bricks are becoming increasingly stringent. Due to its significant advantages over dispersed and through-hole permeable bricks in terms of erosion resistance and adjustable permeability, slotted permeable bricks have become the most widely used type of permeable brick for ladle construction.

[0004] Slotted permeable bricks are made by embedding a polyester substrate (melting point 250-280℃) during the core molding process. The substrate burns away during the high-temperature firing process, forming gaps and channels to achieve air permeability.

[0005] The substrates used in the preparation of slotted permeable bricks are all strip-shaped substrates. Generally, the surface of the substrate is relatively smooth, the thickness is about 0.10-0.20mm, and the width of the substrate is 10-25mm. After the permeable brick is fired and formed, the sides of the slot are also relatively smooth. The width of the slot is 0.10-0.20mm, the length is 10-25mm, and the shape is rectangular when viewed from the cross-section.

[0006] During use, the permeable brick is located at the bottom of the ladle. Molten steel seeps into the permeable brick along the narrow slits, solidifying in the cooler areas and clogging the pores. This seepage and blockage at the slits affects the lifespan of the permeable brick. When the seepage reaches a depth of 10-15mm, continued use requires hot repair with oxygen combustion to burn away the steel and permeable brick material blocking the ventilation channels, creating new ventilation paths. Once the required airflow is reached, the permeable brick can continue to be used. If 10-15mm is burned away each time, the lifespan of the permeable brick will be very short, typically only 25-35 heats. Utility Model Content

[0007] This invention addresses the problem of steel seepage and blockage at the slits in current slotted permeable bricks, which affects the lifespan of the bricks. It provides a substrate for the production of permeable bricks, which reduces the depth of steel seepage and improves the lifespan of slotted permeable bricks after sintering using this substrate.

[0008] The technical solution adopted in this utility model is as follows: A substrate for producing permeable bricks includes a substrate body, wherein the substrate body is a polyester substrate, and at least one end face of the substrate body is a rough end face. By treating the surface of the substrate body to make it rough, the surface roughness is increased compared to conventionally used substrate surfaces. When the substrate is pre-embedded within the permeable brick during molding, the two sides of the gaps formed by the substrate burning during the high-temperature firing process become rough, increasing the specific surface area on both sides of the gaps. This requires a higher wetting surface energy when molten steel wets the sides, thus reducing the flow rate of molten steel during the steel infiltration process and consequently reducing the amount of steel infiltrated.

[0009] As a preferred embodiment of this utility model, the surface roughness Ra of the rough end face is 30μm-50μm.

[0010] As a preferred embodiment of this utility model, the two end faces of the substrate body are rough end faces.

[0011] As a preferred embodiment of this utility model, the total thickness of the rough end face accounts for no more than half of the thickness of the substrate body; the thickness of the substrate body is 100-200μm.

[0012] The rough end face of the substrate can be obtained by physical or chemical methods.

[0013] When physical methods are used, they can be mechanical grinding, sandblasting, or laser etching of micron-level trenches.

[0014] When mechanical polishing is used, sandpaper, grinding machines, etc. can be used to mechanically polish the surface of the substrate.

[0015] When sandblasting is used, the surface of the substrate is sandblasted using sandblasting equipment, and the abrasive used can be alumina or silicon carbide particles.

[0016] When laser etching is used, micron-sized trenches are etched on the surface of the substrate using a laser.

[0017] When using chemical methods, strong alkalis or strong oxidants can be used to chemically etch the substrate surface, or solvent swelling treatment can be used.

[0018] When using strong alkaline etching, strong alkaline solutions such as NaOH solution can be used to etch the surface of the substrate.

[0019] When etching with a strong oxidizing agent, chromic acid solution can be used to etch the surface of the substrate.

[0020] When solvent swelling is used, the substrate can be briefly soaked in solvents such as acetone or tetrahydrofuran (THF) to make the surface of the substrate slightly dissolve and then quickly dry to form a rough structure.

[0021] Any other surface treatment method can be used as long as the surface of the substrate can be roughened.

[0022] This invention treats the permeable brick with a pre-embedded calcination material, i.e., a substrate, to roughen its surface. This roughens the two sides of the sintered slit, increasing the specific surface area on both sides of the slit. When molten steel wets the sides, a higher wetting surface energy is required, which reduces the flow rate of molten steel during the steel infiltration process, thereby reducing the amount of steel infiltrated, which in turn reduces the length of the blockage. Consequently, the oxygen burning time is reduced, the damage caused by oxygen burning to the permeable brick is reduced, and the lifespan of the permeable brick is increased. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of this utility model.

[0025] Figure 2 This is a cross-sectional view of the present invention. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Example 1: A substrate for the production of breathable bricks includes a substrate body 1, wherein the substrate body 1 is a polyester substrate, and at least one end face of the substrate body 1 is a roughened end face 2. Preferably, both end faces of the substrate body are processed into roughened end faces 2, and the surface roughness Ra of the roughened end face 2 is 30μm-50μm, wherein the surface roughness Ra can be 30μm, 35μm, 40μm, 45μm, or 50μm. In this embodiment, the shape of the substrate body is shown as a long strip, such as... Figure 1 and 2As shown, the shape is not limited to a long strip; it can also be an arc shape, etc.

[0028] The total thickness of the substrate body is 100-200μm; the total thickness of the rough end face accounts for no more than half of the total thickness of the substrate body.

[0029] In this embodiment, the total thickness of the substrate body is 180 μm; the total thickness of the two roughened end faces is 80 μm, accounting for 44.4% of the total thickness of the substrate body; and the thicknesses of the two roughened end faces can be the same or different, and their surface roughness can also be the same or different. The roughened end faces of the substrate body can be obtained by physical methods or chemical methods.

[0030] When physical methods are used, they can be mechanical grinding, sandblasting, or laser etching of micron-level trenches.

[0031] When mechanical polishing is used, sandpaper, grinding machines, etc. can be used to mechanically polish the surface of the substrate.

[0032] When sandblasting is used, the surface of the substrate is sandblasted using sandblasting equipment, and the abrasive used can be alumina or silicon carbide particles.

[0033] When laser etching is used, micron-sized trenches are etched on the surface of the substrate using a laser.

[0034] When using chemical methods, strong alkalis or strong oxidants can be used to chemically etch the substrate surface, or solvent swelling treatment can be used.

[0035] When using strong alkaline etching, strong alkaline solutions such as NaOH solution can be used to etch the surface of the substrate.

[0036] When etching with a strong oxidizing agent, chromic acid solution can be used to etch the surface of the substrate.

[0037] When solvent swelling is used, the substrate can be briefly soaked in solvents such as acetone or tetrahydrofuran (THF) to make the surface of the substrate slightly dissolve and then quickly dry to form a rough structure.

[0038] Any other surface treatment method can be used as long as the surface of the substrate can be roughened.

[0039] After surface treatment, the substrate is embedded in the permeable brick during the molding process and then fired at high temperature. The substrate burns away to form a narrow channel. Because the surface of the substrate is rough, the two sides of the narrow channel formed after burning also become rough, which increases the specific surface area on both sides of the narrow channel. The wettability of molten steel on both sides of the narrow channel becomes worse. Molten steel needs a higher wetting surface energy to wet the sides, which reduces the flow rate of molten steel during the steel infiltration process, thereby reducing the amount of steel infiltration. The reduced amount of steel infiltration also reduces the length of the blockage, which in turn reduces the oxygen burning time. The damage caused by oxygen burning to the permeable brick is also reduced, and the service life of the permeable brick is improved.

[0040] The reason why the permeable bricks prepared using the substrate of this invention can reduce the wettability of molten steel is as follows: The relationship between the wettability of molten steel on the surface of refractory materials and surface roughness is a complex phenomenon that follows basic wetting theory and can be summarized by the Wenzel model: surface roughness amplifies the intrinsic wettability of refractory materials; while the intrinsic wettability between refractory materials and molten steel is determined by their chemical composition and interfacial energy. Generally, molten steel (liquid iron-carbon alloy) has an intrinsic contact angle θ > 90° (commonly ranging from 100° to 140°) with oxide refractory materials (such as Al2O3, MgO, ZrO2), indicating a non-wetting or liquid-phobic state.

[0041] The Wenzel model indicates that when a droplet completely wets the grooves of a rough surface (Wenzel state), the apparent contact angle θ * The relationship with the intrinsic contact angle θ is as follows: cosθ * = r * cosθ; Where r is the roughness factor (r = actual surface area / projected geometric surface area, r>1).

[0042] Since the apparent contact angle θ of molten steel is greater than 90° for most oxide refractory materials, increasing the surface roughness of the refractory material will reduce the apparent contact angle θ. * It becomes larger, further reducing wettability.

[0043] Example 2: A substrate for the production of breathable bricks, wherein one end face of the substrate body is a rough end face, and the rest are the same as in Example 1.

[0044] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0045] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A substrate for the production of breathable bricks, comprising a substrate body (1), characterized in that: The substrate body (1) is a polyester substrate, and at least one end face of the substrate body (1) is a rough end face (2).

2. The substrate for producing breathable bricks according to claim 1, characterized in that: The surface roughness of the rough end face (2) is 30μm-50μm.

3. The substrate for producing breathable bricks according to claim 2, characterized in that: The two end faces of the substrate body (1) are rough end faces (2).

4. The substrate for producing permeable bricks according to any one of claims 1-3, characterized in that: The total thickness of the rough end face accounts for no more than 1 / 2 of the thickness of the substrate body.

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