Double-layer crucible structure

Abstract

The utility model discloses a double-layer type crucible structure which comprises a crucible inner layer and a crucible outer layer which are arranged in a nested mode, the outer wall of the crucible inner layer is tightly attached to the inner wall of the crucible outer layer, the crucible inner layer is a cast iron layer, the crucible outer layer is a heat-resisting stainless steel layer, and the thickness of the crucible inner layer is larger than that of the crucible outer layer. The crucible inner layer and the crucible outer layer are nested, the crucible inner layer is made of a pure iron material, magnesium and pure iron do not react, magnesium alloy liquid cannot be polluted at the high temperature, the heat conductivity of iron is good, and the smelting efficiency of the crucible can be improved; the outer layer of the crucible is made of a heat-resistant stainless steel material, so that the outer layer of the heat-resistant stainless steel crucible protects the outer surface of the crucible from being oxidized in a high-temperature working environment. Due to the structural design that the crucible inner layer and the crucible outer layer are nested, the crucible has the advantages of being long in service life, low in energy consumption, free of pollution to a magnesium alloy solution, high in heating speed and low in manufacturing cost.

Description

Technical Field

[0001] The utility model relates to the field of equipment manufacturing for smelting special materials, in particular to a double-layer crucible structure. Background Art

[0002] Magnesium alloy is the lightest known metal structural material (magnesium's specific gravity is about 2 / 3 of aluminum). It has a series of advantages such as low density, high specific strength and specific stiffness, good electrical conductivity, thermal conductivity, shock absorption, magnetic shielding and recyclability, which makes it widely used in automobiles, aircraft, computers and communication equipment. Magnesium alloy has good die-casting molding performance, and the minimum wall thickness of die-casting parts can reach 0.5mm, which is suitable for manufacturing various die-casting parts, so die-cast magnesium alloy parts have been widely used.

[0003] Since magnesium alloy materials are very active, they will react chemically with many metals or non-metals and oxides, which puts very stringent requirements on the materials of magnesium alloy melting crucibles. Magnesium alloy melting crucibles are high-temperature service parts, and the normal working temperature is about 800℃ (the melting point of magnesium is about 700 degrees). Under high-temperature working environment, the melting crucible is also subject to the tension of magnesium alloy solution, corrosion of magnesium alloy solution, corrosion of air or other gases, etc., so the melting crucibles of magnesium and magnesium alloys must have some special properties, such as the inner wall of the melting crucible does not react with the magnesium alloy solution, the oxidation resistance of the crucible surface, high temperature strength and high temperature creep resistance, certain pressure resistance and shock resistance, etc. Due to the special chemical properties of magnesium alloy materials, the materials available are very limited, and combined with cost considerations, the available materials are even more scarce.

[0004] A composite crucible for melting magnesium and magnesium alloys disclosed in a Chinese invention patent (publication number: CN1670458A) is a composite crucible made of a bimetallic crucible made of heat-resistant steel or nickel-based high-temperature alloy and carbon steel and a ceramic material: the inner layer is a ceramic material with excellent properties such as oxidation resistance and heat resistance, and the ceramic material will not react with magnesium and magnesium alloys. The middle layer is a carbon steel material, and the outer layer is a heat-resistant steel or nickel-based high-temperature alloy material. The outer layer prevents oxidation and shedding of the crucible at high temperatures; the middle carbon steel layer avoids high-temperature oxidation; the inner ceramic layer prevents the corrosion of the crucible metal material by high-temperature molten metal and corrosive gases, avoiding secondary pollution during the melting process. However, the high cost of this metal-ceramic composite crucible prepared by laser coating and explosive welding technology is difficult to accept in ordinary civilian production, and the thermal conductivity of ceramics is extremely poor, and the energy consumption is high, which reduces the melting efficiency of the crucible and increases the melting cost.

[0005] From the above, it can be seen that designing a magnesium alloy melting crucible with low cost, long service life, low energy consumption, no pollution to magnesium alloy solution, and fast heating speed has become an urgent problem to be solved in this technical field. Utility Model Content

[0006] The utility model aims to provide a double-layer crucible structure with a long service life, low energy consumption, no pollution to magnesium alloy solution, fast heating speed and low manufacturing cost in view of the defects and shortcomings of the prior art.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] A double-layer crucible structure comprises a nested crucible inner layer and a crucible outer layer, wherein the outer wall of the inner layer of the crucible is tightly fitted with the inner wall of the outer layer of the crucible, the inner layer of the crucible is a cast iron layer, the outer layer of the crucible is a heat-resistant stainless steel layer, and the thickness of the inner layer of the crucible is greater than the thickness of the outer layer of the crucible.

[0009] Furthermore, the thickness of the inner layer of the crucible is 15-35 mm.

[0010] Furthermore, the thickness of the outer layer of the crucible is 5-8 mm.

[0011] Furthermore, the inner layer of the crucible and the outer layer of the crucible are welded and bonded together after evacuation.

[0012] Furthermore, the mouth of the outer layer of the crucible is provided with a crucible flange extending outward.

[0013] Furthermore, a crucible cover plate is arranged on the top of the crucible flange.

[0014] Furthermore, the upper surface A of the inner layer of the crucible is flush with the upper surface B of the outer layer of the crucible.

[0015] After adopting the above structure, the utility model has the following beneficial effects: the double-layer crucible structure described in the utility model comprises a nested crucible inner layer and a crucible outer layer, the outer wall of the crucible inner layer is closely fitted with the inner wall of the crucible outer layer, the crucible inner layer is a cast iron layer, the crucible outer layer is a heat-resistant stainless steel layer, and the thickness of the crucible inner layer is greater than the thickness of the crucible outer layer. The crucible inner layer and the crucible outer layer are nested, the crucible inner layer is made of pure iron material, magnesium and pure iron will not react, and will not pollute the magnesium alloy liquid at high temperature, and iron has good thermal conductivity, which can improve the melting efficiency of the crucible, but iron has extremely poor high-temperature oxidation resistance, and the melting temperature of magnesium alloy needs to be around 800 degrees. Using pure iron material alone to make a crucible will greatly affect the service life of the crucible. Selecting heat-resistant stainless steel material as the crucible outer layer just makes up for this defect. In a high-temperature working environment, the crucible outer layer of heat-resistant stainless steel protects the crucible surface from oxidation. The structural design of the nested arrangement of the inner layer of the crucible and the outer layer of the crucible makes the melting crucible have the advantages of long service life, low energy consumption, no pollution to the magnesium alloy solution, fast heating speed, and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present utility model, the drawings required for use in the description of the specific implementation methods will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0018] Figure 2 It is a sectional view of the overall structure of the utility model.

[0019] Figure 1 to Figure 2 The bid number is:

[0020] 1. Inner layer of crucible; 11. Upper surface A; 2. Outer layer of crucible; 21. Upper surface B; 3. Crucible flange. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0022] In the description of the present invention, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0024] In the present invention, unless otherwise clearly defined and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] In the present utility model, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this utility model are only for illustrative purposes and do not represent the only implementation method.

[0027] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] like Figure 1 to Figure 2 As shown, the utility model provides:

[0029] Embodiment 1

[0030] A double-layer crucible structure comprises a nested crucible inner layer 1 and a crucible outer layer 2, wherein the outer wall of the crucible inner layer 1 is closely attached to the inner wall of the crucible outer layer 2, the crucible inner layer 1 is a cast iron layer, the crucible outer layer 2 is a heat-resistant stainless steel layer, and the thickness of the crucible inner layer 1 is greater than that of the crucible outer layer 2. The crucible inner layer 1 and the crucible outer layer 2 are welded and attached after vacuuming.

[0031] Based on the above embodiments, the utility model aims to solve the problem of providing a double-layer crucible structure, including a nested crucible inner layer 1 and a crucible outer layer 2, wherein the outer wall of the crucible inner layer 1 is tightly fitted with the inner wall of the crucible outer layer 2, the crucible inner layer 1 is a cast iron layer, the crucible outer layer 2 is a heat-resistant stainless steel layer, and the thickness of the crucible inner layer 1 is greater than the thickness of the crucible outer layer 2. The melting point of magnesium is around 700°C. In order to ensure the performance of the magnesium alloy melt in the crucible, the crucible for melting magnesium alloy materials must be heated to 800°C~850°C when in use. This temperature is much lower than the melting point of iron (the melting point of iron is around 1500°C). Therefore, the inner layer 1 of the crucible is made of pure iron material, which will not pollute the magnesium alloy liquid, and the thermal conductivity of iron is good, which can improve the melting efficiency of the crucible; the outer layer 2 of the crucible is made of heat-resistant stainless steel material, which has the characteristics of high high-temperature strength, high-temperature oxidation resistance, and strong corrosion resistance. However, the heat-resistant stainless steel contains alloy elements such as Ni and Cu. Once the elements come into contact with the high-temperature magnesium alloy liquid, they are easily replaced and dissolved into the magnesium alloy liquid. Ni and Cu elements have always been harmful elements of magnesium alloys. Once a small amount of Ni and Cu elements enter the magnesium alloy, the mechanical properties and corrosion resistance of the alloy will drop sharply. Therefore, heat-resistant stainless steel materials with excellent performance have to be rejected by magnesium alloys. However, using heat-resistant stainless steel materials as the outer layer 2 of the crucible perfectly utilizes its advantages and avoids its disadvantages. The outer layer 2 of the crucible is made of heat-resistant stainless steel material. Under high-temperature working conditions, the surface of the inner layer 1 of the pure iron crucible can be protected from oxidation. The structural design of the nested arrangement of the inner layer 1 of the crucible and the outer layer 2 of the crucible makes the smelting crucible have the advantages of long service life, low energy consumption, no pollution to the magnesium alloy solution and fast heating speed, and the manufacturing cost is low. In this embodiment, the inner layer 1 of the crucible and the outer layer 2 of the crucible are welded and bonded after vacuuming. The bonding arrangement of the inner layer 1 of the crucible and the outer layer 2 of the crucible makes the thermal conductivity of the smelting crucible better, is more conducive to saving energy consumption, and improves the smelting efficiency of the magnesium alloy.

[0032] As another preferred embodiment of the utility model, the thickness of the crucible inner layer 1 is 15 mm. The thickness of the crucible outer layer 2 is 5 mm. In this embodiment, if the crucible inner layer 1 is set too thick, it will affect the thermal conductivity of the melting crucible, increase energy consumption, and reduce the melting efficiency of the magnesium alloy. The crucible outer layer 2 mainly protects the crucible inner layer 1 to prevent the outer surface of the crucible inner layer 1 from being oxidized. If the crucible outer layer 2 is set too thick, it is not conducive to cost saving.

[0033] As another preferred embodiment of the present invention, the mouth of the crucible outer layer 2 is provided with a crucible flange 3 extending outward. A crucible cover plate (not shown) is provided on the top of the crucible flange 3. The upper surface A11 of the crucible inner layer 1 is flush with the upper surface B21 of the crucible outer layer 2. In this embodiment, Figure 1 , Figure 2 As shown, due to the strong chemical activity of magnesium alloy, the magnesium alloy solution will quickly oxidize and burn in the air. The contact between the magnesium alloy and the air can be reduced by setting a crucible cover plate on the top of the crucible flange 3. In a further embodiment, a gas protection method can be used, that is, an inert gas or a protective gas that can react with the magnesium alloy to form a dense protective film is introduced to the upper surface of the magnesium alloy solution to isolate the air and prevent the magnesium alloy melt from continuous oxidation and combustion. The gas protection method has a good protection effect, does not pollute the magnesium alloy melt, and has less loss of magnesium alloy melt during melting.

[0034] Embodiment 2

[0035] This embodiment provides a double-layer crucible structure, the main structure and related principles of which are the same as those of the first embodiment, except that:

[0036] The thickness of the inner layer 1 of the crucible is 25 mm. The thickness of the outer layer 2 of the crucible is 6.5 mm.

[0037] Embodiment 3

[0038] This embodiment provides a double-layer crucible structure, the main structure and related principles of which are the same as those of the first embodiment, except that:

[0039] The thickness of the inner layer 1 of the crucible is 35 mm. The thickness of the outer layer 2 of the crucible is 8 mm.

[0040] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present utility model.

Claims

1. A double-layer crucible structure, comprising a nested crucible inner layer (1) and a crucible outer layer (2), characterized in that: The outer wall of the crucible inner layer (1) is tightly fitted with the inner wall of the crucible outer layer (2); the crucible inner layer (1) is a cast iron layer, the crucible outer layer (2) is a heat-resistant stainless steel layer, and the thickness of the crucible inner layer (1) is greater than the thickness of the crucible outer layer (2).

2. A double-layer crucible structure according to claim 1, characterized in that: The thickness of the crucible inner layer (1) is 15-35 mm.

3. A double-layer crucible structure according to claim 1 or 2, characterized in that: The thickness of the crucible outer layer (2) is 5-8 mm.

4. A double-layer crucible structure according to claim 1, characterized in that: The crucible inner layer (1) and the crucible outer layer (2) are welded and bonded together after evacuation.

5. A double-layer crucible structure according to claim 1, characterized in that: The mouth of the crucible outer layer (2) is provided with a crucible flange (3) extending outwards.

6. A double-layer crucible structure according to claim 5, characterized in that: A crucible cover plate is arranged on the top of the crucible flange (3).

7. A double-layer crucible structure according to claim 1, characterized in that: The upper surface A (11) of the inner layer (1) of the crucible is flush with the upper surface B (21) of the outer layer (2) of the crucible.

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