System and method for forging and pressing liquid metal through ultrahigh-pressure argon

Abstract

The invention belongs to a liquid metal forging and crystallizing technology, and particularly relates to a system and a method for forging and pressing liquid metal by ultrahigh-pressure argon, which are characterized in that the molecular spacing is greatly reduced when the metal is solidified through contractility generated when the liquid metal is cooled and solidified and 360-degree ultrahigh-pressure gas pressure applied by the outside, so that grain-refined solid metal is formed; comprising an ultrahigh-pressure forging and pressing container 1 and a roasting box 2 which are fast to open and close, a gap exists between the roasting box 2 and the ultrahigh-pressure forging and pressing container 1, and a coil pipe 3 used for cooling the temperature in the ultrahigh-pressure forging and pressing container is arranged at the position of the gap, and is characterized in that a graphite cover 5 with a one-way valve 4 is arranged above the roasting box 2, and a gas guide pipe 6 is arranged on the side wall of the roasting box 2; a mesh plate 7 is arranged in the middle of a bottom plate of the roasting box 2, an upper air inlet of an air guide pipe 6 is movably connected with the one-way valve 4, a lower air outlet of the air guide pipe 6 is communicated with meshes 7, a support 8 used for installing a mold shell 16 is arranged in the roasting box 2, and a heating and heat preservation device 9 is arranged on the upper portion of the support 8.

Description

Technical Field

[0001] The invention belongs to liquid metal forging crystallization technology, and specifically relates to a system and method for forging liquid metal with ultra-high pressure argon gas. Background Art

[0002] The density of metal structure of casting is not as good as that of forging. The density of die casting is improved, but the structure of die casting is disordered because it has no solidification sequence, which is the worst casting in terms of performance. Extrusion molding also has no cooling sequence and cannot achieve the consistency of structure. Hot isostatic pressing presses solid and cannot make the product dense, let alone produce fine grain structure. Summary of the invention

[0003] The purpose of the present invention is to provide a system and method for forging liquid metal with ultra-high pressure argon gas. Through the contraction force generated when the liquid metal is cooled and solidified and the 360° ultra-high pressure gas pressure applied from the outside, the molecular distance is greatly reduced when the metal solidifies, forming a fine-grained solid metal, thereby greatly improving the various properties of the solid metal; through the optimization of the structural design and coordination method, a feasible systematic forging equipment and forging method are achieved.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a system for forging liquid metal with ultra-high pressure argon gas, comprising an ultra-high pressure forging container and a roasting box, wherein there is a gap between the roasting box and the ultra-high pressure forging container, a coil for cooling is provided in the gap, a graphite cover with a one-way valve is provided on the top of the roasting box, an air guide pipe is provided on the side wall of the roasting box, a mesh is provided on the bottom of the roasting box, one end of the air guide pipe is connected to the one-way valve, and the other end is connected to the mesh, a bracket for installing a mold shell is provided inside the roasting box, an insulation device is provided above the bracket, and an air port for connecting ultra-high pressure argon gas is provided on the top of the ultra-high pressure forging container.

[0005] Preferably, it further comprises an upper cover, the air port is arranged on the upper cover, and the upper cover is lifted and lowered by a cylinder.

[0006] Preferably, the heat-insulating device is a heating coil and is located at the pouring cup of the mold shell.

[0007] Preferably, it further comprises an ultra-high pressure container, a compressor and an argon tank, wherein the argon tank is connected to the ultra-high pressure container via the compressor, and the ultra-high pressure container is connected to the gas port.

[0008] To achieve the above object, the present invention provides the following technical solution: an ultra-high pressure argon liquid metal forging method, comprising:

[0009] Step 1: The argon tank pressurizes the argon gas through a compressor and stores it in an ultra-high pressure container;

[0010] Step 2: Open the upper cover and the graphite cover through the cylinder, put the mold shell with liquid metal into the bracket of the baking box, and then evacuate the air port to make the ultra-high pressure container in a vacuum state. At this time, the heat preservation device is used to keep the pouring cup of the mold shell warm;

[0011] Step 3: The graphite cover is placed on the step of the ultra-high pressure forging container, and the position is above the roasting box to keep the one-way valve of the graphite cover connected with the air guide pipe of the roasting box, and then the upper cover is closed on the ultra-high pressure forging container through the cylinder and locked;

[0012] Step 4: When the metal in the mold shell is in liquid state, the low-temperature and low-pressure argon gas in the argon tank (15) is introduced into the ultra-high pressure forging container through the gas port, and the low-temperature and low-pressure argon gas is cooled and pressurized. The argon gas is injected into the upper part of the graphite cover in the ultra-high pressure forging container for buffering, and then enters the air guide pipe through the one-way valve, and then blown to the bottom of the roasting box through the air guide pipe;

[0013] Step 5: After buffering, the air is blown to the bottom of the mold shell and around the entire mold shell through the mesh plate, cooling the pressurized mold shell and the liquid metal in the mold shell from bottom to top, and the mold shell has a certain air permeability;

[0014] Step 6: As the liquid metal gradually cools and pressurizes, the distance between molecules shrinks and the grains become smaller, producing a fine-grained structure.

[0015] Step 7: During the cooling, pressurizing and shrinking process of the liquid metal in the mold shell, the heating and heat preservation device always heats and insulates the pouring cup of the mold shell, so that the metal in the pouring cup remains in liquid and semi-solid state, and the metal that shrinks into the mold shell is continuously fed;

[0016] Step eight, when the liquid metal in the mold shell becomes solid fine-grained material through cooling and pressurization, release argon gas into multiple ultra-high pressure containers 13, and after balance, put it into the next one, and so on, until it reaches a safe low pressure and is released into the atmosphere, then open the forging container and take out the casting forging product.

[0017] Preferably, during the cooling process of the liquid metal, a cooling medium is introduced into the coil to further achieve controllable cooling speed of the metal in the mold shell 16 .

[0018] Preferably, in the pressurization stage in step 4, gradient pressurization is adopted, and the ultra-high pressure forging container can be pressurized step by step in a gradient manner.

[0019] Preferably, in the decompression stage in step eight, gradient decompression is adopted to perform gradient step-by-step decompression in the ultra-high pressure forging container.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention utilizes the strong contraction force of liquid metal during the transformation from liquid phase to solid phase and the centripetal gas pressure of 360° in the external direction, so that the molecular distance of the metal is greatly compressed during solidification, thereby forming a fine-grained structure, and the method of introducing and pressurizing ultra-high pressure gas is also combined with the cooling direction and cooling state of the liquid metal, and the liquid metal in the mold shell is timely compensated for shrinkage, thereby ensuring the molding effect of the liquid metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a system structure diagram of the present invention;

[0022] Figure 2 It is a schematic structural diagram of the ultra-high pressure forging vessel of the present invention.

[0023] Marking instructions: 1. Ultra-high pressure forging vessel; 2. Baking box; 3. Coil; 4. One-way valve; 5. Graphite cover; 6. Air guide tube; 7. Mesh; 8. Bracket; 9. Insulation device; 10. Air port; 11. Upper cover; 12. Cylinder; 13. Ultra-high pressure vessel; 14. Compressor; 15. Argon tank; 16. Mould shell. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The crystal structure of metal materials can be divided into single crystal, columnar crystal, polycrystalline and fine crystal. The so-called fine crystal means that the grains of metal materials are very fine, and the premise for the formation of fine crystals in metal materials is that the gaps between molecules / atoms are highly dense.

[0026] But how to achieve high density of gaps between molecules / atoms is precisely the key to the problem. As we all know, the contraction force of liquid metal during cooling is very strong and amazing. The basic theory in the field of casting technology is to follow the minimum shrinkage ratio of about 1:1-3 according to the size of the product's hot spot. Under such a process, it can only ensure that the product does not produce coarse grains, looseness, and shrinkage cavities. During the cooling and solidification process, the metal liquid basically shrinks nearly 10% of its volume, and this contraction force is extremely strong.

[0027] Similarly, diamonds are also formed by crystallization in a high temperature and high pressure environment during crustal changes. People have used this principle to invent equipment for artificially producing diamonds. It is composed of six tungsten-cobalt alloy top hammers. The pressure of the oil cylinder is used to press the six-sided top blocks centripetally onto the catalyst. The result is also called artificial diamond.

[0028] There are many ways to improve the density of metals in the existing technology. For example, my country has produced an 80,000-ton forging press, which can produce large forgings, but cannot make the material highly dense because it presses solids and applies pressure in one direction. It increases the density of the material, but cannot achieve the highly dense effect formed when the liquid is transformed into a solid. In addition, there is the hot isostatic pressing method, which places the material in an ultra-high pressure container for heating and uses ultra-high pressure argon gas to forge the product 360°. Because it is gas pressure, it will not destroy the product structure, it increases the density of the material and improves the physical and chemical properties of the product.

[0029] In order to improve the performance of materials, people selectively combine and melt metals and non-metals, try to develop formulas to improve material performance, and add elements such as niobium and molybdenum to refine the grains. However, fine crystals cannot be formed and the various properties of the materials cannot be significantly improved.

[0030] After the fine crystals are formed, the heat resistance, corrosion resistance, erosion resistance, wear resistance, tensile strength and elongation of the metal material will be rapidly improved. Its functional design, safety performance and service life will also have a qualitative leap.

[0031] With regard to the background technology, ultra-high pressure argon forging liquid metal, that is, precision casting heating isostatic pressing, not only ensures the principle of sequential cooling and sequential solidification of precision casting, but also ensures the consistency of the organization. When the liquid metal is cooled and solidified from liquid to solid, the liquid metal molecules are in a free state. When it cools itself, the distance between molecules will be reduced, and at the same time, the pressure of ultra-high pressure argon is added. The distance between molecules is further reduced, forming a highly dense structure, and the grains are reduced accordingly, until a fine-grained organization is produced.

[0032] The technical solution of the present invention includes a system of the present invention for forging liquid metal with ultra-high pressure argon gas, including an ultra-high pressure forging container 1 and a roasting box 2 with quick opening and closing, a gap between the roasting box 2 and the ultra-high pressure forging container 1, a coil 3 for cooling the temperature in the ultra-high pressure forging container is provided at the gap, a graphite cover 5 with a one-way valve 4 is provided above the roasting box 2, an air guide pipe 6 is provided on the side wall of the roasting box 2, a mesh plate 7 is provided in the middle of the bottom plate of the roasting box 2, an upper air inlet of the air guide pipe 6 is movably connected with the one-way valve 4, and a lower air outlet is connected with the mesh 7. After passing through the mesh plate hole, the bottom of the blow mold shell is cooled, forcing the liquid metal in the mold shell to be cooled and pressurized from bottom to top, forcing the metal liquid to follow the principle of sequential cooling and sequential crystallization) the roasting box 2 is provided with a bracket 8 for installing the mold shell, a heating and heat preservation device 9 is provided on the upper part of the bracket 8, and an air inlet pipe 10 is provided on the upper cover of the ultra-high pressure forging container 1; the power supply is introduced from the ultra-high pressure forging container cover and connected to the heating and heat preservation device through the graphite cover.

[0033] The entire ultra-high pressure argon forging liquid metal operating system is controlled automatically by electricity, and can also be controlled manually. The control target is: argon forging liquid metal first starts from low temperature and low pressure, with smooth buffering, and gradually cools and pressurizes until it reaches high pressure. The liquid metal molecules are in a free state. Through cooling and pressurization, the distance between molecules begins to shrink when the liquid metal cools. The ultra-high pressure argon plays a role in fueling the situation. The compression force plus the pressure of 360-degree ultra-high pressure, under the pressure of the superposition of these two forces, the distance between molecules shrinks further, the density increases further, the crystal grains also shrink, and a fine-grained structure is produced. At this point, the material's heat resistance, corrosion resistance, wear resistance, erosion resistance, tensile strength, and elongation will be geometrically improved.

[0034] It also includes an upper cover 11 , the air intake pipe 10 is arranged on the upper cover 11 , and the upper cover 11 is lifted and lowered by a cylinder 12 .

[0035] The heat preservation device 9 is a heating coil and is located at the pouring cup of the mold shell.

[0036] It also includes an ultra-high pressure container 13 , a compressor 14 and an argon tank 15 . The argon tank 15 is connected to the ultra-high pressure container 13 through the compressor 14 , and the ultra-high pressure container 13 is connected to the air intake pipe 10 .

[0037] The present invention is an understanding and combination of the two processing technologies of ultra-high pressure argon forging liquid metal and forging. When the metal is in a liquid state, the metal molecules are in a free state. The liquid metal in the mold shell 16 is placed in the baking box 2. Under the forging pressure of ultra-high pressure argon gas and in the state of self cooling and shrinkage, the distance between the metal molecules is naturally contracted. Combined with the centripetal pressure of the ultra-high pressure gas in all directions of 360°, the distance between the metal molecules is artificially reduced under the superposition of the two forces of metal shrinkage rate and gas pressure, forming a highly dense, and the grains also become smaller. , forming a fine-grained structure, while forging is to heat and forge solid metal in one direction. Its metal molecules are not in a free state, and the distance between molecules is already stable. Although heating and pressurizing cannot completely change the distance between metal molecules, and the result of forging in one direction will only tear the metal fibers and destroy the metal structure. The structure of ultra-high pressure argon forging liquid metal is complete and evenly arranged because the gas pressure is based on the 360° centripetal pressure of the liquid metal, and because the metal molecules are in a free state, the pressure on the metal molecules is equal. It can also completely and regularly reduce the distance between metal molecules. This is also the fundamental difference between the two processing technologies of forging and ultra-high pressure argon forging liquid metal.

[0038] The ultra-high pressure argon liquid metal forging method of the present invention comprises:

[0039] Step 1: The argon tank 15 pressurizes the argon gas through the compressor 14 and stores it in the ultra-high pressure container 13;

[0040] Step 2: Open the upper cover 11 and the graphite cover 5 through the cylinder 12, and put the mold shell with liquid metal into the bracket 8 of the roasting box 2. The mold shell itself has very dense pores, which can keep the gas connected with the inside and outside of the mold shell, and the metal liquid cannot flow out from the inside of the mold shell. The heat preservation device 9 is used to keep the pouring cup of the mold shell warm. At this time, the metal in the mold shell is in liquid state.

[0041] Step 3: Cover the graphite cover 5 on the baking box 2, keep the one-way valve 4 of the graphite cover 5 connected with the air guide pipe 6 of the baking box 2, and then cover the upper cover 11 on the ultra-high pressure forging container 1 through the cylinder 12;

[0042] Step 4: When the metal in the mold shell is in a liquid state, the ultra-high pressure container 13 starts to pressurize through the air inlet pipe 10. After the ultra-high pressure argon gas is introduced into the ultra-high pressure forging container 1, it is first located above the graphite cover 5. First, the graphite cover 5 can block the introduced high pressure argon gas to achieve a buffering effect, thereby effectively protecting the mold shell and the liquid metal in the mold shell from being damaged by the high pressure argon gas that is pressed in instantly, and making the gas pressure of the outer wall of the liquid metal in the mold shell stable and gradually increase; secondly, when the low temperature argon gas under the graphite cover meets the high temperature of the liquid metal in the mold shell, the graphite cover 5 The gas pressure below will be instantly increased, and at the same time, the graphite cover 5 itself is air-permeable, which can reduce the pressure difference between the top and bottom of the graphite cover 5; prevent the graphite cover from being lifted up or displaced; furthermore, since the graphite itself has heat resistance and heat preservation properties, the temperature above the graphite cover 5 is always kept at a low temperature, thereby effectively protecting the structure and seals above the graphite cover 5; and the pressure outside the mold shell is changed from a boosting state to a pressure-maintaining state, thereby providing a stable 360° centripetal pressure for the liquid metal in the mold shell during the process of transitioning from liquid phase to solid phase.

[0043] The graphite cover 5 and the baking box 2 are kept sealed while gradually filling up the upper part of the ultra-high pressure forging container 1, and further passing through the one-way valve 4 on the graphite cover 5 and the air guide pipe 6 into the bottom of the baking box 2;

[0044] Step 5: After passing through the mesh 7, the argon gas in the air guide pipe 6 pressurizes and cools the liquid metal in the mold shell from the bottom to the top. Since the pouring cup of the mold shell 16 is located above the mold shell, the liquid metal in the mold shell itself is cooled from the bottom to the top, and a metal shell with a certain hardness will be formed on the outside during the cooling process. The direction of the ultra-high pressure argon gas is the same as the solidification direction of the liquid metal, providing further ultra-high pressure 360° pressure to the external hard metal shell.

[0045] Step 6: When the liquid metal is cooled in the mold shell and changes from liquid to solid, the contraction force of the metal during cooling and the pressure of the ultra-high pressure gas jointly form a highly dense, fine-crystalline solid metal from the free liquid metal;

[0046] Step 7: During the solidification process of the liquid metal in the mold shell, the heat preservation device 9 always keeps the pouring cup of the mold shell warm, so that the metal in the part is in liquid state, and provides real-time shrinkage compensation for the solidification process of the metal in the mold shell; keep the liquid state for 4 to 5 minutes, and after 5 to 15 minutes, the liquid metal is in a state of cooling and pressurization. The liquid metal is in a state of superposition of cooling and solidification shrinkage and ultra-high pressure argon gas pressure (metal shrinkage and ultra-high pressure gas pressure) to make the metal highly dense (precision casting mold shell has a certain air permeability), the distance between molecules is reduced, the crystal phase structure is reduced, and fine-grained structure materials are produced, so that various physical and chemical properties are rapidly improved; the container releases the pressurized gas to the multi-stage pressure container one by one, and finally enters the atmosphere at low pressure;

[0047] Step 8: After the liquid metal in the mold shell 16 is transformed from a free state into a fine-crystalline solid, the argon gas in the air inlet pipe 10 is discharged into the ultra-high pressure container 13 again.

[0048] During the cooling process of the liquid metal, a cooling medium is introduced into the coil 3 to further control the cooling speed of the metal in the mold shell 16. The ultra-high pressure container 13 is composed of several

[0049] In the pressurization stage in step 4, a gradient pressurization is used to gradually increase the pressure in the ultra-high pressure container; this ensures that the external gas pressure increases synchronously while the outer surface of the metal in the mold shell gradually hardens. Otherwise, when the outer shell of the metal in the mold shell is soft, a higher air pressure is suddenly introduced, which will press the liquid metal in the entire mold shell into droplets. In the decompression stage in step 8, a gradient decompression is used to gradually reduce the pressure in the ultra-high pressure container. The purpose of this is to protect the seals and pipelines in the entire ultra-high pressure forging container 1. Finally, the ultra-high pressure container is opened to take out the casting product.

[0050] The entire internal system of the container, including the graphite cover, pipelines, roasting box and insulation device, can ensure that the liquid metal is cooled and solidified sequentially from bottom to top, thereby achieving consistent crystallization.

[0051] The graphite cover has heat-resistant, heat-insulating and breathable properties, which protects the upper sealing ring of the graphite cover to work at a lower temperature, buffers the pressure of the gas on the mold shell, and can balance the pressure above and below the graphite cover.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A system for forging liquid metal with ultra-high pressure argon, comprising an ultra-high pressure forging container (1) and a roasting box (2) with a quick opening and closing, wherein a gap is provided between the roasting box (2) and the ultra-high pressure forging container (1), and a coil (3) is provided in the gap for cooling the temperature in the ultra-high pressure forging container, characterized in that: A graphite cover (5) with a one-way valve (4) is provided above the roasting box (2), an air guide pipe (6) is provided on the side wall of the roasting box (2), a mesh plate (7) is provided in the middle of the bottom plate of the roasting box (2), an upper air inlet of the air guide pipe (6) is movably connected to the one-way valve (4), and a lower air outlet is communicated with the mesh (7), a bracket (8) for installing a mold shell (16) is provided inside the roasting box (2), a heating and heat preservation device (9) is provided on the upper part of the bracket (8), and an air inlet pipe (10) is provided on the upper cover of the ultra-high pressure forging container (1).

2. The system for forging liquid metal with ultra-high pressure argon as claimed in claim 1, characterized in that: It also comprises an upper cover (11), the air intake pipe (10) is arranged on the upper cover (11), and the upper cover (11) is lifted and lowered by a cylinder (12).

3. The system for forging liquid metal with ultra-high pressure argon as claimed in claim 1, characterized in that: The heat preservation device (9) is a heating disk resistance wire and is located around the pouring cup of the mold shell (16).

4. The system for forging liquid metal with ultra-high pressure argon as claimed in claim 1, characterized in that: It also includes an ultra-high pressure container (13), a compressor (14) and an argon gas tank (15); the argon gas tank (15) is connected to the ultra-high pressure container (13) through the compressor (14); and the ultra-high pressure container (13) is connected to the air intake pipeline (10).

5. An ultra-high pressure argon liquid metal forging method, characterized in that: include: Step 1: The argon gas tank (15) pressurizes the argon gas through the compressor (14) and stores it in the ultra-high pressure container (13); Step 2: Open the upper cover (11) and the graphite cover (5) through the cylinder (12), put the mold shell with liquid metal into the bracket (8) of the roasting box (2), and then evacuate the air through the air port (10) to make the ultra-high pressure container (13) in a vacuum state. At this time, the heat preservation device (9) is used to keep the pouring cup of the mold shell warm; Step 3: The graphite cover (5) is placed on the step of the ultra-high pressure forging container (1), and is positioned above the roasting box (2) to keep the one-way valve (4) of the graphite cover (5) connected to the air guide pipe (6) of the roasting box (2), and then the upper cover (11) is closed on the ultra-high pressure forging container (1) through the cylinder (12) and locked; Step 4: When the metal in the mold shell is in a liquid state, the low-temperature and low-pressure argon gas in the argon tank (15) is introduced into the ultra-high pressure forging container (1) through the gas port (10), and the low-temperature and low-pressure argon gas is cooled and pressurized. The argon gas is injected into the upper part of the graphite cover (5) in the ultra-high pressure forging container (1) for buffering, and then enters the air guide pipe (6) through the one-way valve (4), and then blown to the bottom of the roasting box (2) through the air guide pipe (6); Step 5: After buffering, the air is blown toward the bottom of the mold shell (16) and around the entire mold shell (16) through the mesh plate (7), cooling the pressurized mold shell (16) and the liquid metal in the mold shell (16) from bottom to top, and the mold shell has a certain air permeability; Step 6: As the liquid metal gradually cools and pressurizes, the distance between molecules shrinks and becomes denser, and the grains also shrink, producing a fine-grained structure. Step 7: During the cooling, pressurizing and shrinking process of the liquid metal in the mold shell (16), the heating and heat-insulating device (9) always heats and insulates the pouring cup of the mold shell (16), so that the metal in the pouring cup remains in a liquid and semi-solid state, and the metal that shrinks into the mold shell is continuously fed back into the mold shell; Step eight, when the liquid metal in the mold shell (16) is cooled and pressurized to become a solid fine-grained material, argon is released into multiple ultra-high pressure containers (13). After equilibrium, the next one is put into the next one, and so on, until it reaches a safe low pressure and is released into the atmosphere. Then, the forging container is opened and the casting forging product is taken out.

6. The ultra-high pressure argon liquid metal forging method according to claim 5, characterized in that: During the cooling process of the liquid metal, a cooling medium is introduced into the coil (3), thereby further achieving controllable cooling speed of the metal in the mold shell (16).

7. The ultra-high pressure argon liquid metal forging method according to claim 5, characterized in that: There are a plurality of ultra-high pressure containers (13), and in the pressurization stage in step 4, a gradient pressurization is adopted, so that the ultra-high pressure forging container (1) can be pressurized step by step in a gradient manner.

8. The ultra-high pressure argon liquid metal forging method according to claim 5, characterized in that: In the decompression stage in step eight, gradient decompression is adopted to perform gradient step-by-step decompression in the ultra-high pressure forging container (1).

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