CN112179135A

CN112179135A - Integrated crucible for smelting metal

Info

Publication number: CN112179135A
Application number: CN202010853807.5A
Authority: CN
Inventors: 赵海斌; 苏尧; 杨勋刚; 阳家文; 胡宇; 鲍永鑫; 姚志勇; 杨红军
Original assignee: Institute of Materials of CAEP
Current assignee: Institute of Materials of CAEP
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2021-01-05

Abstract

The invention discloses an integrated crucible for smelting metal, which sequentially comprises a ceramic lining, a transition layer, a buffer layer and a shell from inside to outside; the transition layer is filled with magnesia particles. The integrated crucible for smelting metal has longer service life.

Description

Integrated crucible for smelting metal

Technical Field

The invention relates to an integrated crucible for smelting metal, and belongs to the technical field of high-temperature induction smelting.

Background

Smelting is a key process for preparing alloy raw materials, and the quality of the alloy raw materials has direct influence on the performance of castings. The graphite crucible has wide application due to good thermal shock resistance, but the graphite is easily reacted with active metal to introduce carbon impurities, so that the graphite crucible is restricted. Compared with a graphite crucible, the ceramic crucible hardly reacts with various metal melts, has the characteristics of low decomposition pressure and vapor pressure, weak electromagnetic shielding, high thermal efficiency and the like, and is widely applied to vacuum induction melting of metals.

At present, a furnace lining knotting process method is adopted in production to fix the ceramic crucible into the induction coil, the crucible knotting process is complicated, the labor intensity is high, and the subsequent disassembly process is also complicated. The ceramic crucible is easy to generate axial cracking in the metal induction melting to cause the failure of the crucible, and the service life of the ceramic crucible seriously restricts the improvement of the production efficiency.

Therefore, it is necessary to provide a ceramic crucible which is convenient and quick to install and has a long service life, so as to solve the problems of complex process of crucible knotting, high labor intensity, short service life and the like.

Disclosure of Invention

The invention aims to: aiming at the existing problems, the invention provides the integrated crucible for smelting metal, and the integrated crucible has the advantages of integrated design, quick assembly and disassembly and longer service life.

The technical scheme adopted by the invention is as follows:

an integrated crucible for smelting metal comprises a ceramic lining, a transition layer, a buffer layer and an outer shell in sequence from inside to outside;

the transition layer is filled with magnesia particles.

In the present invention, the ceramic liner, transition layer, buffer layer and shell are of a coaxial design and have a similar shape, the shape being the normal crucible shape. The ceramic lining is a melting component with a cavity. The shell plays a supporting role for increasing the integral strength of the structural part, and the induction coil is insulated and isolated in the internal structure and assembled with the induction coil. The buffer layer is soft material and is located avoiding and interior bottom surface in the shell, and the transition layer between buffer layer and the ceramic inside lining is filled with the magnesia granule. The transition layer is filled with magnesia particles, so that thermal shock generated by smelting metal can be resisted, good supporting strength is provided for the ceramic lining, the crucible is not easy to crack in the using process through buffering of the buffer layer, the crucible has longer service life, and the crucible can be quickly installed or detached as a whole through the integrated design; the problems of complex crucible knotting process, high labor intensity and short service life in the prior art are solved.

It should be noted that, in the smelting process, as the metal is heated sharply, a large temperature difference is generated inside the metal, so that a large impact thermal stress is caused, the magnesite has good thermal shock resistance, the influence of thermal shock on the crucible can be reduced by filling magnesite particles in the transition layer, and the buffer layer is used for further buffering, so that the influence of thermal shock on the crucible is minimized, and the service life of the crucible is prolonged to the maximum extent by the structure design of hard-soft-hard from the inside to the outside.

Preferably, the material of the ceramic lining is one or more of calcium oxide, aluminum oxide, magnesium oxide, silicon oxide, beryllium oxide and boron nitride.

In the scheme, the special ceramic lining made of one or more materials of calcium oxide, aluminum oxide, magnesium oxide, silicon oxide, beryllium oxide and boron nitride has high temperature resistance and good thermal stability, and does not react with most metals;

preferably, the buffer layer is made of asbestos cloth.

Preferably, the thickness of the buffer layer is 2-5 mm.

In above-mentioned scheme, the asbestos cloth buffer layer can play the effect of buffering thermal shock.

Preferably, the material of the shell is one or more of calcium oxide, aluminum oxide and magnesium oxide.

Preferably, in the transition layer, the upper part of the transition layer is a bonding layer formed by a mixture of magnesia and a binder, and the lower part of the transition layer is a magnesia filling layer.

Preferably, the height of the adhesive layer is 20 to 70 mm.

In the scheme, the magnesia is used as a transition layer of the main body, the lining, the buffer layer and the shell are connected into a whole, and meanwhile, the magnesia can resist thermal shock and provide good support strength for the lining; the bonding layer formed after the upper magnesite and the bonding agent are solidified enables the transition layer to be fixed between the lining and the buffer layer, and the magnesite cannot be spilled out.

Preferably, in the mixture of the magnesite and the binder, the mass ratio of the binder is 2-5%.

Preferably, in the mixture of the magnesia and the binder, the mass ratio of the binder is 3.5 percent

In the above scheme, if the adhesive is too little, the adhesive effect is not good, and the desired effect cannot be achieved; if too much binder is added, the hardness after curing is too high, the effect of resisting heat shock of magnesite cannot be achieved, and the optimal effect can be achieved when the binder accounts for 2% -5%, and preferably 3.5%.

Preferably, the binder is water glass.

Preferably, the magnesia is baked at the temperature of 300-600 ℃ for 2-5 h.

In above-mentioned scheme, the magnesite is through toasting the back, and the magnesite granule is compacter hard, can not take place the shrink in high temperature environment to make the thermal stability of transition layer better, the refractoriness is better, uses repeatedly and can keep the magnesite granule size stable, provides stable good support strength for the inside lining, improves the life of crucible.

Preferably, the magnesite comprises coarse magnesite and fine magnesite, the particle size of the coarse magnesite is 1 mm-4 mm, and the particle size of the fine magnesite is less than 1 mm.

In the above scheme, in the transition layer that forms after coarse magnesia and fine magnesia mix, the space that coarse magnesia formed can be filled to fine magnesia to make the transition layer compacter, the structure is more stable, thereby can provide better stable support intensity for the inside lining, improves crucible life. And when the particle size of the coarse magnesia is 1 mm-4 mm and the particle size of the fine magnesia is less than 1mm, the coarse magnesia and the fine magnesia can be mixed for use to achieve better thermal shock resistance.

Preferably, the ratio of the coarse magnesite to the fine magnesite is 3: 1-2.

In the scheme, the ratio of coarse magnesia to fine magnesia is 3: 1-2, the filling effect is better, the compactness is better, the formed transition layer is more stable, the thermal shock resistance is better, and the service life of the crucible is longer.

Preferably, the end face of the upper part of the ceramic lining is higher than the end face of the outer shell.

In the scheme, the melt can be prevented from contacting the induction coil in the tilting casting process after the smelting is finished, so that the safety of the smelting process is ensured.

According to the integrated crucible for smelting metal, the thermal shock can be resisted to the greatest extent through the structural design of hard-soft-hard outside the inner band, particularly through the optimized proportion and particle size selection of magnesia with different particle sizes in the transition layer, the influence of the thermal shock on the crucible is better reduced, and the service life of the crucible is prolonged; and through carrying out heat treatment on the magnesia, the stability of the transition layer is further improved, the shock resistance of the transition layer is improved, and the service life of the crucible is prolonged.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the integrated crucible for smelting metal can be quickly installed and detached;

2. the integrated crucible for smelting metal has long service life.

Drawings

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic view of the structure of an integral crucible;

FIG. 2 is another schematic view of the structure of the one-piece crucible;

FIG. 3 is a schematic view of the assembly of the integrated crucible and induction coil.

The labels in the figure are: 1-ceramic lining, 2-transition layer, 3-buffer layer, 4-shell, 5-induction coil, 21-adhesive layer and 22-magnesia filling layer.

Detailed Description

All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.

Any feature disclosed in this specification may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.

In the embodiment, the crucible is in the shape of a cylindrical crucible, and the bottom of the crucible is a flat bottom, but the shape of the crucible can be other common shapes according to the requirement.

Example 1

As shown in fig. 1, the integrated crucible for melting metal of the present embodiment sequentially includes, from inside to outside, a ceramic lining, a transition layer, a buffer layer and an outer shell;

the transition layer is filled with magnesia particles;

wherein the ceramic lining is made of calcium oxide, and the end surface of the upper part of the lining is higher than the end surface of the shell;

the buffer layer is made of 3mm asbestos cloth; the shell is made of magnesium oxide;

the transition layer is filled with magnesia particles baked for 3 hours at 500 ℃, and the magnesia is coarse magnesia with the particle size of 3mm and fine magnesia with the particle size of 0.5mm, and the weight ratio of the magnesia to the transition layer is 3: 1 proportion of mixed magnesia; the transition layer comprises a magnesia filling layer at the lower part and a bonding layer with the upper part height of 30mm, wherein the bonding layer is formed by adding 3.5 percent of water glass into magnesia.

Example 2

The difference between this embodiment and embodiment 1 is that the material of the ceramic lining in this embodiment is alumina.

Of course in other embodiments, the ceramic liner may be other one or combination of more of calcium oxide, aluminum oxide, magnesium oxide, silicon oxide, beryllium oxide, and boron nitride.

Example 3

The difference between this embodiment and embodiment 1 is that in this embodiment, the material of the housing is calcium oxide. Of course, in other embodiments, the material of the housing may be alumina or a combination of more than one of calcium oxide, aluminum oxide, and magnesium oxide.

Example 4

The difference between this example and example 1 is that, in this example, the ratio of coarse magnesite to fine magnesite in the transition layer is 3: 2.

of course, in other embodiments, the ratio of coarse magnesite to fine magnesite in the transition layer may be 3: 1-2.

Example 5

The present example is different from example 1 in that the coarse magnesite grain size is 1mm and the fine magnesite grain size is 0.3 mm.

Of course, in other embodiments, the coarse magnesite grain may have other grain sizes ranging from 1 to 4mm, and the fine magnesite grain may have other grain sizes less than 1mm, so that the difference between the grain sizes of the coarse magnesite grain and the fine magnesite grain is greater than 0.5 mm.

Example 6

The difference between this embodiment and embodiment 1 is that in this embodiment, the bonding layer is magnesite with 5% water glass added.

In other embodiments, the bonding layer is magnesite with water glass added in any other proportion of 2-3.5%.

Comparative example 1

This comparative example used an induction crucible of common molten metal.

Comparative example 2

This comparative example differs from example 1 in that no transition layer was provided in this comparative example.

Comparative example 3

This comparative example is different from example 1 in that the comparative example is not provided with a buffer layer.

Comparative example 4

The comparative example differs from example 1 in that the magnesite in the transition layer in the comparative example is single coarse magnesite.

Comparative example 5

The comparative example differs from example 1 in that the magnesite in the transition layer in the comparative example is single fine magnesite.

Comparative example 6

The comparative example differs from example 1 in that the coarse magnesite and the fine magnesite in the comparative example are mixed according to a ratio of 5: mixing at a ratio of 1.

Comparative example 7

The comparative example differs from example 1 in that the coarse magnesite and the fine magnesite in the comparative example are mixed according to a ratio of 1: mixing at a ratio of 1.

Comparative example 8

The difference between this comparative example and example 1 is that the bonding layer in this comparative example is magnesia with 10% water glass added.

In the above examples and comparative examples, the service life of the crucible was tested by comparing actual tests. In examples 1 to 3, the service life of the crucible was 15 times; the service life of examples 4 to 6 was 14 times. Compared with the common crucible in the comparative example 1, the service life of the integrated crucible is 8 times, and the service life of the integrated crucible is greatly prolonged by 70-90% compared with that of the normal common crucible.

In comparative example 2, the service life of the crucible was 5 times. By comparison with example 1, it can be seen that the service lives of the two are greatly different, and therefore the magnesia transition layer plays a key role in increasing the service life in the present invention.

In comparative example 3, the service life of the crucible was 12 times. By comparison with example 1, the buffer layer in combination with the transition layer can further increase the service life of the crucible.

In comparative example 4, the service life of the crucible was 11 times. By comparison with example 1, it can be seen that the service life of the coarse magnesite alone is not as long as that of example 1, because the coarse magnesite alone has relatively large voids, making the structure unstable and thus the service life relatively low.

In comparative example 5, the service life of the crucible was 12 times. By comparison with example 1, it can be seen that the use of fine magnesite alone is not as long as the service life of example 1 is high, because although the transition layer is denser after the fine magnesite alone is filled, the service life is reduced because too dense it weakens the ability to withstand thermal shock.

In comparative example 6, the service life of the crucible was 12 times. By comparison with example 1, the service life of the comparative example is shorter than that of example 1, because the proportion of the fine magnesite is lower, the fine magnesite cannot completely fill the gap of the coarse magnesite, the magnesite formed by mixing the fine magnesite and the coarse magnesite is not high in structural stability, and the service life of the magnesite is shorter than that of example 1.

In comparative example 8, the service life of the crucible was 13 times. By comparison with example 1, the service life of this comparative example was shorter than that of example 1, and also the service life was reduced because the structure of the transition layer after mixing was too dense due to an excessively high amount of fine magnesia.

In comparative example 9, the service life of the crucible was 12 times. By comparison with example 1, the proportion of water glass in this comparative example is too high, so that the hardness of the adhesive layer after curing is too high, the ability to resist thermal shock becomes weak, and the service life is reduced.

In conclusion, the integrated crucible for smelting metal can be quickly installed and disassembled, and has long service life.

The invention is not limited to the foregoing embodiments. The invention extends to any novel feature or any novel combination of features disclosed in this specification and any novel method or process steps or any novel combination of features disclosed.

Claims

1. An integral type crucible of smelting metal which characterized in that: the ceramic lining, the transition layer, the buffer layer and the shell are sequentially arranged from inside to outside;

the transition layer is filled with magnesia particles.

2. The single-piece crucible for melting metal of claim 1, wherein: the ceramic lining is made of one or more of calcium oxide, aluminum oxide, magnesium oxide, silicon oxide, beryllium oxide and boron nitride.

3. The single-piece crucible for melting metal of claim 1, wherein: the material of buffer layer is asbestos cloth.

4. The single-piece crucible for melting metal of claim 1, wherein: the shell is made of one or more of calcium oxide, aluminum oxide and magnesium oxide.

5. The single-piece crucible for melting metal of claim 1, wherein: in the transition layer, the upper part of the transition layer is a bonding layer formed by a mixture of magnesia and a bonding agent, and the lower part of the transition layer is a magnesia filling layer.

6. A one-piece crucible for melting metal as recited in claim 5, wherein: in the mixture of the magnesia and the adhesive, the mass ratio of the adhesive is 2-5%.

7. The single-piece crucible for melting metal of claim 1, wherein: the magnesia is baked at the temperature of 300-600 ℃ for 2-5 h.

8. The single-piece crucible for melting metal of claim 1, wherein: the magnesite comprises coarse magnesite and fine magnesite, the particle size of the coarse magnesite is 1-4mm, and the particle size of the fine magnesite is smaller than 1 mm.

9. The single-piece crucible for melting metal of claim 8, wherein: the ratio of the coarse magnesia to the fine magnesia is 3: 1-2.

10. The single-piece crucible for melting metal of claim 1, wherein: the end face of the upper part of the ceramic lining is higher than the end face of the shell.