RU2744635C1 - Method of manufacturing lining for metallurgical equipment in the form of a melting or filling device using additive technologies - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to metallurgy, in particular to methods for manufacturing the lining of thermal units, metal-melting and metal-casting devices using additive technology. It can be used in foundry, metallurgical production and heat power engineering for lining of electrolyzers in aluminum production, slag bowls, steel ladles, and induction furnaces. The formation of thermal insulation, reinforcement and working layers of the lining is performed sequentially by layer-by-layer extrusion of mixtures corresponding to the layer being laid from the 3D printer print head with automatic change of mixtures in accordance with a 3D computer model, ensuring the formation of a monolithic lining structure of a given geometry. The reinforcing layer in the bottom of the device is formed simultaneously with the reinforcing layer of the walls, and in the slag zone and the bottom zone of the walls of the device working layer is made thick.EFFECT: invention provides increased accuracy of the geometry and dimensions of the lining, increased speed of its production and possibility of continuous sequential lining with different materials.4 cl, 3 dwg

Description

Technology area

The invention relates to the field of foundry, metallurgical production and heat power engineering, namely to methods of manufacturing lining of thermal units, metal-smelting and metal-casting devices, electrolyzers in aluminum production and other devices, including lining of slag bowls, steel-pouring ladles, induction furnaces, oxygen converters and others equipment for metallurgical production (hereinafter referred to as devices) using additive technology using 3D printers.

State of the art

Lining is an internal or external protective layer of equipment, which is applied to it in order to create reliable protection against the influence of negative factors of the operating environment.

Depending on the purpose of the purpose, the lining can be acid-resistant, refractory, heat-insulating, shock-resistant and others.

At present, the most common methods of lining metal-smelting and metal-pouring devices are: type-setting (brick fireclay) lining; rammed / pouring lining; single crucible / segmented lining, shotcrete lining.

Brick lining is a widely used traditional lining, but it has a number of disadvantages: the need for frequent replacement of the lining, laboriousness of the lining process, long drying and installation process.

Segmental lining saves time for its installation, it is used with a total weight of the lining over a ton, but the presence of seams, as in the case of traditional brick lining, reduces the resource.

Crucible Liners are ready-to-use liners that are inserted directly into the device. The advantages of this type of lining in comparison with other technologies: the use of molded linings gives a significant reduction in lining time; there is no need for long-term drying of the lining according to a complex schedule, there is no need to use templates, mixers, etc., the dependence of the quality of the lining on the human factor is reduced, since the quality of the molded lining is guaranteed by the manufacturer.

However, the lining in the form of a single crucible installed in the device is not always applicable due to the gradual operational deformation of the devices themselves. In addition, the manufacture and installation of large size gels (over a ton) is not convenient.

The technology of making the rammed lining includes the installation of a special template in the ladle, followed by filling with a refractory mass.

The technology of filling the lining includes the installation of a special template into the ladle with further filling of the liquid mass into the template, which fills the mold under the action of gravity and vibration. After the material has hardened, the template is removed and drying takes place at a predetermined temperature regime.

Advantages of rammed and flooded linings in comparison with brick fireclay lining: reduction of ladle preparation time, increase in lining durability by 2 or more times, increase in manufacturability of preparation of the device for operation.

The application of the lining with the help of shotcrete installations is technologically advanced and allows the formation of linings of large linear dimensions, incl. in thickness due to the application of several layers of shotcrete, however, it also has a number of disadvantages, such as: the difficulty of obtaining a lining layer uniform in thickness, the need for preparatory reinforcement when forming a working layer that is significant in thickness.

To ensure minimum heat losses and high resistance with a relatively low weight, multilayer thin-walled linings are used. The three-layer lining consists of heat-insulating (leveling), reinforcing and working layers made of various materials that determine the design of the bottom and wall lining in accordance with the operating conditions of metal-melting and metal-pouring devices.

Known traditional methods do not allow technologically to form these layers, to produce a monolithic lining with a precisely specified geometry and thickness of the coatings.

The basis of 3D printing technology is the principle of layer-by-layer creation (growth) of a solid object, as a result of which the object is formed by layer-by-layer laying of the building material to the height of the formed layer, until the given geometry of the product is created completely corresponding to the computer 3D model.

In the technology of three-dimensional printing of products, various materials can be used: metal and ceramic powders, liquid resins, wax, plastic, various sheet materials, composite materials (from cellulose compounds, special fibers and other additives, a mixture of foundry sand and additives), building mixtures based on cement, gypsum, chamotte clay.

In all known cases, regardless of the design of the printer (gantry, with angular coordinates based on robots - manipulators), the printers are equipped with extruders that allow you to simultaneously feed the mixture, accumulate the mixture, dose it using CNC-based actuators, if necessary, introduce various additives directly into the extruder, exclude spontaneous outflow of the building mixture with a shut-off valve, mix the building mixture in the extruder container in order to avoid delamination and clumping of the mixture, use mixtures that are different in their characteristics and purpose.

It is known from the prior art to manufacture linings by traditional methods, for example, to manufacture a lining of a steelmaking converter from bricks (see [1] RF patent No. 2291902, IPC S21S 5/44, publ. 03/20/2013). The published patent describes the sequence and arrangement of the lining by laying out the insulating layer, the reinforcing layer and the working layer with bricks of various refractory materials.

The disadvantages of this analog are:

- labor intensity of the lining process and the influence of the "human factor" as a result of the use of manual labor;

- a long time spent on the brickwork of the lining, which affects the duration of the downtime of the device for repair;

- heterogeneity of the lining caused by the presence of joints between bricks filled with refractory compositions, which affects the number of cycles and resource;

- low wear resistance of the lining;

- low adhesion between the device body, heat-insulating, reinforcing and working layers;

- the complexity of controlling the geometry of the lining;

- the complexity of manufacturing and integration of communications for metal-smelting and metal-casting devices.

The closest analogue to the claimed invention in terms of a set of features taken as a prototype is a method for manufacturing a lining of a steel-pouring ladle (see [2] RF patent No. 2558703, IPC B22D 41/02, publ. 08.10.2013). The patent describes a method for manufacturing a monolithic lining by gunning with subsequent compaction of the applied layer. In this solution, it is proposed to apply only the working layer of the lining.

The disadvantages of the prototype are:

• production of monolithic heat-insulating and reinforcing layers is not provided;

• only the lining of the cylindrical surfaces of devices (walls) is made and it is impossible to make a monolithic bottom of the device;

• it is impossible to make projections and channels of complex configuration;

• it is possible to adjust the thickness of the lining, but it is impossible to make the lining with different thickness in different places of the device;

• it is impossible to use different materials for the manufacture of different layers of lining: heat-insulating, reinforcing and working.

The essence of the invention

The technical problem facing the invention is to eliminate the disadvantages of analogs and expand the functionality.

The technical result of the claimed invention is an increase in the accuracy of the geometry and dimensions of the lining, a significant increase in the rate of lining of metal-melting and metal-pouring devices, automation of the lining process, the possibility of quick changeover of equipment (3D printer) for lining metal-melting and metal-pouring devices of different geometries, the possibility of continuous sequential lining of heat-insulating and reinforcement and working layers with different materials, the possibility of arranging lining of different thickness in different places of the device.

According to the invention, the technical problem is solved, and the technical result is achieved due to a method for manufacturing a lining for metallurgical equipment in the form of a melting or pouring device using additive technologies, containing the formation of heat-insulating, reinforcing and working layers of the lining, and the formation of lining layers is performed sequentially by layer-by-layer extrusion of mixtures, corresponding to the layer to be laid, from the print head of a 3D printer when automatically changing mixtures in accordance with a computer 3D model, ensuring the formation of a monolithic lining structure of a given geometry, while the reinforcing layer of the bottom of the device is formed simultaneously with the reinforcing layer of the walls, and in the area of the slag belt and in the lower belt of the walls of the device, the working layer is thickened.

Also, the technical problem is solved, and the technical result is achieved due to the fact that the heat-insulating layer is formed using shimot clay or quartz clay materials, the reinforcing layer is formed using fire clay materials, and the working layer is formed using refractories.

Also, the technical problem is solved, and the technical result is achieved due to the fact that the lining is made with high geometric accuracy.

Also, the technical problem is solved, and the technical result is achieved due to the fact that a lining is made with protrusions and channels of complex geometry.

Brief Description of Drawings

Figure 1 is a sequence of lining an induction steel furnace.

Figure 2 is a sequence of the lining of the oxygen converter.

Figure 3 is a sequence of lining a steel-pouring ladle.

The following positions are indicated in the figures:

1 - 3D printer for printing lining;

2 - induction steel-making furnace;

3 - oxygen converter;

4 - steel ladle;

5 - heat-insulating layer of the lining;

6 - reinforcing layer of the lining;

7 - working layer of the lining.

Implementation of the invention

The additive manufacturing technology of the lining includes the formation of heat-insulating (5), reinforcing (6) and working layers (7) of a lining for a metal-melting or metal-pouring device using a 3D printer.

Manufacturing (printing) of lining using 3D printers, for example, construction printers, using additive technology (layer-by-layer deposition technology) allows the formation of heat-insulating, reinforcing and working layers of metal-melting and metal-pouring devices from various materials used in these layers, with precisely specified geometry of the lining required thicknesses of layers, allows you to automate the lining process, significantly reduce the time and the impact of the "human factor".

For printing a heat-insulating (leveling) layer, you can use, but not only: fire clay or quartz clay powders, moistened to 7-10%. The print material is applied in layers to the entire inner surface of the device. Surface leveling (in the case of imperfect geometry of metal-melting and metal-pouring devices) when laying the thermal insulation layer can be performed automatically with geometry correction based on the measurement data of the device, for example, but not only by scanning. To reduce heat loss in the main lining, the thermal insulation layer can be printed from, for example, but not limited to, asbestos-containing or kaolin materials.

The reinforcement layer provides thermal insulation to create stable casting conditions, and also guarantees safety in the event of a breach of the working layer. The printing of the reinforcing layer is performed, for example, from, but not only, chamotte-clay materials. The thickness of this layer can be formed in layers in several passes of the print head and thus vary, if necessary, in thickness.

The bottom reinforcement layer can be formed simultaneously with the fabrication of the reinforcement layer of the device walls, since no personnel is required inside the device itself to make the lining. Accordingly, the joints of the bottom with the walls of the lined device are excluded, which increases its reliability and resource. Traditionally, the bottom lining is carried out separately and the joint of the bottom lining with the wall lining is a technologically weak point.

The working layer of the lining, which is in direct contact with the melt, wears out quickly, determining the overall durability of the device. When determining the required printable thickness of the working layer, the topography of its wear along the height and perimeter of the device is taken into account. Refractories wear unevenly. For example, in metal casting devices, increased wear of refractories is observed in the area of the slag belt and in the lower belts of the walls. This is due to the longer exposure of the lower parts of the lining to the melt and the high hydrostatic pressure, which increases the metal impregnation of the refractories. Applying a lining using 3D printers allows, due to the application of additional layers, to form a thicker working layer in these parts of metal-melting and metal-pouring devices.

In addition to the above, additive technology allows the formation of complex surfaces inside metal smelters and metal casting devices, for example, but not limited to, ledges on the bottom of metal casting ladles, which trap slag and channels that direct metal to the outlet.

The additive technology of manufacturing the lining of metal-smelting and metal-pouring devices is carried out by the formation of lining layers by extrusion and layer-by-layer stacking of mixtures corresponding to the layer to be laid using a 3D printer. The heat-insulating (5), reinforcing (6) and working (7) layers of devices are sequentially formed layer by layer.

The mixtures are successively extruded from the print head of a 3D printer, forming a given geometry of the lining of a metal-melting or metal-casting device in accordance with the control code and in accordance with a computer 3D model of the lining, thus obtaining a monolithic lining structure.

The 3D printer (1) can be installed on the device itself, as an example in FIG. 1 shows the installation of a 3D printer on the body of an induction steel-making furnace (2), Fig. 2 shows the installation of a 3D printer on the body of the oxygen converter (3), Fig. 3 shows the installation of a 3D printer over the body of a steel-pouring ladle (4).

The 3D printer (1) can be located in the shop where the lining is made, and the device itself, for example, the steel-pouring ladle (4), during the lining is placed in the working area of the printer.

Automation of the lining process consists in the fact that the lining itself is created in the form of a 3D computer model that takes into account the geometry of the device, the creation of a control code for a 3D printer and printing of the lining in automatic mode with minimal human intervention, which allows eliminating the "human factor" and obtaining high quality and accurate lining geometry.

The use of computer modeling and the use of 3D printers (1) makes it possible to manufacture complex lining of various thicknesses in different parts of metal-melting and metal-pouring devices. In addition, when printing a lining on 3D printers, it is possible to manufacture protrusions and channels of devices that are complex in their geometry.

The use of a 3D printer (1) makes it possible to use mixtures of different composition for different layers of lining (heat-insulating (5), reinforcing (6) and working (7)), which can be changed automatically and repeatedly in the 3D printer extruder.

For printing linings for various purposes, the following materials can be used, but not only, the following materials: cement (Portland cement), sand (silicon dioxide, olivine, chromite, zircon, alumina, mullite, mullite corundum, quartz glass, chamotte, spinel, corundum-spinel, corundum and quartzite) , gypsum, asbestos, modifying, anti-freezing, hydrophobic and fire-resistant additives, plasticizers, fiber fibers, hardening accelerators (retarders), water, and composite materials based on lignin and cellulose.

The additive manufacturing technology of the lining is carried out as follows.

A 3D printer is installed on equipment foundry, metallurgical or other production, such as an induction steel-making furnace, an oxygen converter, a steel-pouring ladle.

The required mixture for the lining is fed into the extruder (print head) of the printer (1) installed on / near the metal-melting or metal-casting device, for example, but not only: on the body of the induction steel-making furnace (2), on the body of the oxygen converter (3), above the steel-pouring bucket (4).

The printer is loaded with a control code, a three-dimensional computer model of the lining and a 3D printer, in accordance with the commands of the control code, forms the layers of the lining, for example, but not only: heat-insulating (5), reinforcing (6) and working (7).

The causal relationship between the technical result and the essential features of the claims is as follows:

- achievement of high quality mechanical characteristics of the lining due to its monolithic design, the possibility of forming any number of lining layers, due to the possibility of changing mixtures of different composition;

- achieving high accuracy of geometric dimensions due to the use of a 3D printer with CNC elements for the lining.

- the ability to print complex lining elements, such as protrusions and channels of devices.

Claims (4)

1. A method of manufacturing a lining for metallurgical equipment in the form of a melting or pouring device using additive technologies, containing the formation of heat-insulating, reinforcing and working layers of the lining, characterized in that the formation of lining layers is performed sequentially by layer-by-layer extrusion of mixtures corresponding to the layer to be laid from a 3D print head printer when automatically changing mixtures in accordance with a 3D computer model, ensuring the formation of a monolithic lining structure of a given geometry, while the reinforcing layer of the bottom of the device is formed simultaneously with the reinforcing layer of the walls, and in the area of the slag belt and in the lower belt of the walls of the device, the working layer is made thicker. 2. A method of manufacturing a lining according to claim 1, characterized in that the heat-insulating layer is formed using shimot clay or quartz clay materials, the reinforcing layer is formed using fire clay materials, and the working layer is formed using refractories. 3. A method of manufacturing a lining according to claim 1, characterized in that the lining is made with high geometric accuracy. 4. A method of manufacturing a lining according to claim 1, characterized in that a lining is made with projections and channels of complex geometry.

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