Manufacturing method of electric heating furnace core and ignition loss mold tool of electric heating furnace core

Abstract

The manufacturing method comprises the following steps: mixing furnace core raw materials, pouring the mixed furnace core raw materials into a cavity between an inner mold and an outer mold which are spirally wound with molybdenum wires, heating by electrifying the molybdenum wires, keeping the whole body in a hydrogen atmosphere, continuously baking and forming for 120 hours at the temperature of 500 + / -10 DEG C, and embedding the molybdenum wires into the inner side wall of the furnace core; and a wood mold strip is padded between the wound molybdenum wire and the inner mold plate and is carbonized and burnt out in a high-temperature baking process, so that the mold plate is convenient to detach and demold. The manufacturing method of the electric heating furnace core is easy to operate and implement, and the ignition loss mold tool is simple in structure, convenient to assemble and disassemble and low in cost.

Description

Technical Field

[0001] The invention belongs to the technical field of refractory equipment, and in particular relates to a method for manufacturing an electric heating furnace core and a burn-out mold tooling thereof. Background Art

[0002] The high-temperature annealing furnace generally used for gem crystal materials is an electric heating furnace. Its heating element is usually a resistance wire coiled into a spiral shape and embedded in the furnace core. When powered on, it generates high temperature and forms a uniform temperature field in the furnace cavity to achieve annealing of gem crystal materials. By adjusting the power, the temperature of the temperature field can be easily controlled to meet the annealing process requirements of the crystal material.

[0003] The maximum operating temperature of the furnace of the above-mentioned electric heating furnace is about 1900°C, and the furnace core needs to be made of refractory materials with a refractoriness of more than 2000°C. Improper annealing operation will cause the furnace core to be damaged and scrapped. The furnace core has a short lifespan, at most more than thirty furnaces, and sometimes even a few furnaces. Therefore, the cost of the furnace core is very high; the furnace core is one of the core components of the annealing furnace, usually cast and formed by mixing a variety of refractory raw materials and additives. The mold used for casting the furnace core is usually made of mold steel, and the demoulding mechanism is complicated, so the mold cost is relatively high. Summary of the invention

[0004] In order to solve the related problems of the above-mentioned high-temperature annealing furnace core, the present invention proposes a method for manufacturing an electric heating furnace core and a burn-out mold tooling thereof. The furnace core is made of a mixture of white corundum sand, alumina hollow balls, and refractory mud, and then phosphoric acid and water are added and stirred evenly, and poured into a cavity between an inner mold and an outer mold with spirally wound molybdenum wire. The molybdenum wire is energized to generate heat, and the whole is placed in a hydrogen atmosphere. The temperature is controlled within the range of 500±10℃, and the core is baked for 120 hours. The molybdenum wire is embedded in the inner wall of the furnace core. The inner and outer molds are both made of metal plates, and a wooden mold strip is padded between the wound molybdenum wire and the inner mold plate, which is carbonized and burned out during the high-temperature baking process, making it convenient to disassemble and demold the mold plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 A three-dimensional diagram of the burn-out mold tooling of the present invention; Figure 2 It is a top view and a cross-sectional view of the burn-out mold tooling of the present invention; Figure 3 It is a schematic diagram of the base of the burn-out mold tooling of the present invention; Figure 4 This is a schematic diagram of a finished furnace core manufactured using the lost mold burnout tooling of the present invention.

[0006] The serial numbers in the above drawings are explained as follows: 1-base, 11-positioning ring groove, 12-external clearance notch, 13-internal clearance notch, 2-outer mold, 21-outer mold plate, 3-wooden mold strip, 31-tooth stage, 4-electric heating wire, 5-inner mold, 51-inner mold plate, 6-positioning piece, 61-positioning card, 7-furnace core. Implementation

[0007] In conjunction with the above drawings, the specific implementation of the present invention is as follows: The burn-out mold tooling of the present invention is composed of a base 1, an outer mold 2, a wooden mold strip 3, an electric heating wire 4, an inner mold 5, and a positioning piece 6.

[0008] The outer mold 2 is composed of multiple arc-shaped metal outer mold plates 21 assembled into a circle, and the inner mold 5 is composed of multiple arc-shaped metal inner mold plates 51 assembled into a circle.

[0009] The base 1 is provided with a positioning ring groove 11, the outer edge of the positioning ring groove 11 is provided with a plurality of outer clearance notches 12, and the inner edge is provided with a plurality of inner clearance notches 13, and the number and position of the outer clearance notches 12 and the inner clearance notches 13 correspond to the joint seams of the outer template 21 and the inner template 51 respectively.

[0010] The outer mold 2 and the inner mold 5 are placed concentrically in the positioning ring groove 11 of the base 1, and the joint seams of the outer mold plate 21 and the inner mold plate 51 correspond to the outer clearance notch 12 and the inner clearance notch 13 respectively.

[0011] A plurality of wooden mould strips 3 are arranged side by side on the outer side of the inner mould 5 , and a plurality of tooth platforms 31 are arranged on the outer side of each wooden mould strip 3 . After the plurality of wooden mould strips 3 are arranged, the circumferential tooth platforms 31 are distributed in an equidistant spiral shape.

[0012] The heating wire 4 is made of molybdenum alloy and is wound around a spiral toothed platform 31 on the outside of the wooden mold strip 3 , with two lead-out ends passing through lead holes to the outside of the outer mold 2 .

[0013] The outer periphery of the positioning member 6 is evenly provided with a plurality of positioning cards 61, the number of the positioning cards 61 is the same as the number of the inner templates 51, the positioning member 6 is placed at the upper end of the inner template 5, and each positioning card 61 is positioned in the middle position of each inner template 51 for support and positioning.

[0014] The quality requirements of the raw materials of the electric heating furnace core of the present invention are: White corundum sand, 100 mesh, alumina content not less than 99%; Alumina hollow balls, 0.5~1mm, alumina content not less than 99%; High alumina refractory clay, refractoriness greater than 1200℃; industrial grade phosphoric acid; filtered water.

[0015] The weight ratio of the above raw materials is: white corundum sand 56%~58%, alumina hollow balls 26%~29%, high alumina refractory clay 5%~6%, phosphoric acid 3%~4%, and water 4~5%.

[0016] The method for manufacturing the electric heating furnace core of the present invention comprises the following steps: Step 1: Mix white corundum sand, hollow alumina balls and high-alumina refractory clay according to the above ratio; Step 2, adding phosphoric acid and water in the above ratio and stirring evenly; Step 3, filling the annular cavity between the outer mold 2 and the inner mold 5 of the tooling with the mixed material and compacting it; Step 4: Move the filled tooling as a whole into a closed space, fill the space with hydrogen atmosphere, and turn on the electric heating wire 4 to generate heat. By adjusting the power, the heating temperature is controlled within the range of 500±10℃. After 120 hours, turn off the power and cool down naturally to room temperature. Step 5: Take out the tooling, dismantle the outer mold 2, take out the inner mold 5, clean up the charcoal slag left by the high-temperature burned wooden mold strip 3, and obtain the following Figure 4 The finished furnace core is shown.

[0017] The manufacturing method of the electric heating furnace core of the present invention is simple to operate and easy to implement. The furnace core manufactured by this method has good thermal shock resistance and a service life of up to 50 to 80 furnace times.

[0018] The lost mold burning tooling of the present invention has a simple structure, is easy to assemble and disassemble, uses cheap materials, and has low cost.

[0019] The above description is an application example of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or similar method made using the content of this patent, or directly or indirectly used in the relevant technical field should be included in the protection scope of this patent.

Claims

1. A method for manufacturing an electric heating furnace core, characterized in that: Mix white corundum sand, hollow alumina balls and refractory clay, add phosphoric acid and water and stir evenly, pour into the cavity between the inner mold and the outer mold with spirally wound molybdenum wire, use the molybdenum wire to generate electricity and heat, and place the whole in a hydrogen atmosphere. The temperature is controlled within the range of 500±10℃ and baked for 120 hours. The molybdenum wire is embedded in the inner wall of the furnace core.

2. The method for manufacturing the electric heating furnace core according to claim 1, characterized in that: The quality requirements of the raw materials of the electric heating furnace core are: white corundum sand, 100 mesh, alumina content not less than 99%; alumina hollow balls, 0.5~1mm, alumina content not less than 99%; high-alumina refractory clay, refractoriness greater than 1200°C; industrial-grade phosphoric acid; filtered water.

3. The method for manufacturing the electric heating furnace core according to claim 1, characterized in that: The weight ratio of the raw materials of the electric heating furnace core is: 56% to 58% of white corundum sand, 26% to 29% of hollow alumina balls, 5% to 6% of high-alumina refractory mud, 3% to 4% of phosphoric acid, and 4% to 5% of water.

4. The method for manufacturing the electric heating furnace core according to claim 1, characterized in that: The production steps of the electric heating furnace core are: Step 1, mixing white corundum sand, hollow alumina balls and high-alumina refractory clay according to the proportions described in claim 3; Step 2, adding phosphoric acid and water in the proportion according to claim 3 and stirring evenly; Step 3, filling the annular cavity between the outer mold (2) and the inner mold (5) of the tooling with the mixed material and compacting it; Step 4: Move the filled tooling as a whole into a closed space, fill the space with hydrogen atmosphere, and turn on the electric heating wire (4) to generate heat. By adjusting the power, the heating temperature is controlled within the range of 500±10°C. After 120 hours, turn off the power and cool down naturally to room temperature. Step 5, take out the tooling, dismantle the outer mold (2), take out the inner mold (5), clean up the charcoal slag remaining on the wooden mold strip (3) burned by high temperature, and obtain the finished furnace core.

5. A tool for burning out mold of an electric heating furnace core, characterized in that: The lost mold tooling for implementing the manufacturing method described in claims 1 to 4 is composed of a base (1), an outer mold (2), a wooden mold strip (3), an electric heating wire (4), an inner mold (5), and a positioning piece (6), and is characterized in that: a plurality of wooden mold strips (3) are arranged side by side on the outer side of the inner mold (5), and a plurality of tooth platforms (31) are arranged on the outer side of each wooden mold strip (3), and the circumferential tooth platforms (31) of the plurality of wooden mold strips (3) are arranged in an equidistant spiral distribution; the electric heating wire (4) is made of molybdenum alloy, and is wound on the spiral tooth platform (31) on the outer side of the wooden mold strip (3), and its two lead ends are passed through the lead holes to the outside of the outer mold (2).

6. The burn-out mold tooling of the electric heating furnace core according to claim 5 is characterized in that: The base (1) is provided with a positioning ring groove (11), the outer edge of the positioning ring groove (11) is provided with a plurality of outer clearance notches (12), and the inner edge is provided with a plurality of inner clearance notches (13), and the number and position of the outer clearance notches (12) and the inner clearance notches (13) respectively correspond to the joint seams of the outer template (21) and the inner template (51).

7. The burn-out mold tooling of the electric heating furnace core according to claim 5 is characterized in that: The outer mold (2) is composed of a plurality of arc-shaped metal outer mold plates (21) assembled into a circle, and the inner mold (5) is composed of a plurality of arc-shaped metal inner mold plates (51) assembled into a circle.

8. The burn-out mold tooling of the electric heating furnace core according to claim 5 is characterized in that: The outer mold (2) and the inner mold (5) are placed concentrically in the positioning ring groove (11) of the base (1), and the joint seams of the outer mold plate (21) and the inner mold plate (51) correspond to the outer clearance notch (12) and the inner clearance notch (13) respectively.

9. The burn-out mold tooling for the electric heating furnace core according to claim 5 is characterized in that: A plurality of positioning cards (61) are evenly arranged on the outer periphery of the positioning member (6), the number of the positioning cards (61) being the same as the number of the inner templates (51), the positioning member (6) being placed on the upper end of the inner template (5), and each positioning card (61) being positioned at the middle position of each inner template (51).

Images