TWI756955B - Method and device for manufacturing a foamed metal and intermediate foaming process - Google Patents

Abstract

A method for manufacturing a foamed metal includes: melting the metal material to form a molten metal soup; injecting gas into the molten metal soup to fill the molten metal soup with bubbles generated by the gas to form a foamed molten metal soup; controlling the working temperature of the foamed molten metal soup in semi-solid temperature range to keep the foamed metal molten stock in a semi-solid state until the internal bubble shape gradually converges to form a target molten metal soup; and, solidifying the target molten metal soup into a foamed metal, wherein the foamed metal is filled with multiple holes that are not completely connected..

Description

Manufacturing method and equipment of foamed metal

The present invention relates to a manufacturing method and equipment of a foamed metal, and in particular, to a manufacturing method and equipment of a foamed metal with an intermediate foaming process.

Foamed metal has excellent characteristics that are different from traditional metals. Taking foamed aluminum metal as an example, foamed aluminum has excellent characteristics such as light weight, heat insulation, and electromagnetic shielding, and is widely used in construction, aerospace and other industries; In order to meet the application needs of various industries, the efficient preparation of foamed aluminum has become the focus of research in the field of metallurgy.

At present, in the preparation method of foamed aluminum, the direct air blowing method refers to the process of introducing gas into the molten metal to produce the bubble material, which has the advantages of low cost and can realize large-scale continuous production. However, in the process of gas injection and foaming, due to the limited surface tension of the bubbles themselves, when the bubbles enter the molten metal, they cannot withstand the effect of the gravity of the molten metal, resulting in the generation of bubbles from its surface inward. collapse situation.

Therefore, in the existing metal foam forming process, there are still many problems such as the inability of the bubbles to contact the metal molten soup effectively and fully, and further problems such as uneven distribution of the bubbles, low foaming rate, etc., which seriously affect the foam metal after the metal foam forming. mechanical properties and their fabrication yields.

The mainland patent application (public notice number CN100422363C) discloses the following: a foaming device for preparing foamed aluminum or foamed aluminum alloy by a melt foaming method. The lower part has a guide hole for the melt in the thickening chamber to flow to the foaming chamber; the thickening chamber is equipped with a viscosity sensor for monitoring the viscosity of the melt and a mixing agitator that can inhale the thickening agent under negative pressure; the foaming Chamber is equipped with negative pressure inhalable foaming agent or foam Gas mixing agitator; an adjustment and supply valve is provided on the inhalation thickener channel of the mixing agitator installed in the viscosity increasing chamber; the inhalation foaming agent or foaming gas channel of the mixing agitator installed in the foaming chamber is provided with Adjust the supply valve. This patent document can conveniently adjust the viscosity of the melt continuously, and maintain the uniformity of the viscosity in the melt. It can also control the intake of the foaming agent or the foaming gas to continuously prepare the foam with different distributions. Density foam aluminum or foam aluminum alloy products.

U.S. Patent (Certificate No. US6984356B2) discloses the following: a method for continuous production of metal foam, comprising the steps of: (i) adding pre-dissolved molten metal into a viscosifying furnace and stirring the molten metal to uniformly maintain the viscosity of the molten metal; (ii) conveying the molten metal to an electronically stirred foaming furnace; (iii) injecting gas into the conveyed molten metal while stirring to obtain a foamed molten metal; (iv) using roll stretching to obtain a foamed molten metal And cool the stretched metal foam. The beneficial effect of the present invention is that: adding a tackifier into a reinforced melting furnace and melting the metal, and stirring the molten metal by an electronic stirring system instead of a mechanical impeller, the foam can be uniformly dispersed in the molten metal.

The Mainland Patent Application (Publication No. CN102962413A) discloses the following: a continuous casting system capable of obtaining closed-cell aluminum foam with a uniform foam body, consisting of a melting furnace (100), a tundish, a continuous foaming furnace, a continuous casting mold and a continuous pulling device It is characterized in that: the intermediate package is equipped with a stirrer to prevent the settling of the melt tackifying particles, and the tundish also has a melt inlet for the melting furnace melt to be transferred into, and a melt tackifying particle is added to the tundish. The particle inlet and the discharge port of the viscosified melt; the continuous foaming furnace is divided into a liquid storage chamber and a foaming chamber by a partition), and the lower part of the partition is left in the liquid storage chamber. The melt can flow to the guide hole of the foaming chamber, the liquid storage chamber is equipped with a stirrer to keep the viscosity-increasing particles uniformly dispersed in the melt, and the foaming chamber is equipped with a vent pipe and a A gas-liquid mixing agitator that ensures that the melt and bubbles enter from the bottom and are fully mixed, the continuous foaming furnace is provided with a chute connecting the discharge port and the liquid storage chamber, and the continuous casting The mold is connected with the foaming chamber, and the continuous casting mold is composed of a graphite inner mold and a water cooling jacket covering the graphite inner mold.

However, none of the above-mentioned patent documents discloses temperature control, pressure maintenance and auxiliary gas injection for the semi-solid metal molten soup containing bubbles, so the bubbles still cannot be combined with the gas. The molten metal is effectively and fully contacted, and there are still many problems such as uneven distribution of bubbles and low foaming rate.

Therefore, there is a need to provide a method and equipment for manufacturing foamed metal to solve the aforementioned problems.

An object of the present invention is to provide a method and equipment for manufacturing foamed metal, which has an intermediate foaming process and can perform temperature control, pressure maintenance and auxiliary gas injection on the foamed metal molten soup.

In accordance with the above purpose, the present invention provides a method for manufacturing foamed metal, comprising: a smelting step of melting a metal material to form a molten metal; a gas injection foaming step of injecting gas into the molten metal to make the metal molten The molten soup is filled with air bubbles generated by the gas to form a foamed metal molten soup; an intermediate foaming step controls the working temperature of the foamed metal molten soup in its semi-solid temperature range, so that the foamed metal molten soup is maintained at semi-solid until the shape of the internal bubbles tends to be uniform, forming a target molten soup; and a casting step, solidifying the target molten soup into a foamed metal, and the foam metal is filled with a plurality of incompletely connected holes.

The present invention further provides a manufacturing equipment for foamed metal, which comprises: connecting a gas injection foaming furnace to the smelting furnace, and injecting gas into a molten metal, so that the molten metal is filled with the gas generated by the gas. The air bubbles form a foamed metal molten soup; a middle foaming chamber is connected to the gas injection foaming furnace to control the working temperature of the foamed metal molten soup in its semi-solid temperature range, so that the foamed metal molten The soup is maintained in a semi-solid state until the shape of its internal bubbles tends to be uniform, forming a target molten soup; and a casting device, connected to the intermediate foaming chamber, is used to solidify the target molten soup into a foamed metal, and the molten metal is formed. The inside of the bubble metal is filled with a plurality of incompletely connected holes.

Since the intermediate foaming process of the manufacturing method of foamed metal of the present invention can control the temperature and maintain the pressure of the molten metal, and can assist in the injection of gas, the bubbles and the molten metal can be effectively and fully formed. Contact, the bubbles are more evenly distributed in the foamed metal molten soup, thereby improving the porous foamed metal pores uniformity. Accordingly, the metal foam manufacturing method and equipment of the present invention can obtain porous metal foam with better mechanical properties and more uniform density, which is an effective improvement over the current metal foam manufacturing method and equipment.

10: Metal Molten Soup

11: Bubbles

12: Flow control valve

2: Gas injection foaming furnace

21: Main air injection port

22: Inside

23: Gas supply

3: Intermediate foaming chamber

30: Foaming control components

311: External

312: Internal

32: Timer

321: molten soup entrance

322: molten soup outlet

33: Locks

34: Turnable bolt

35: Auxiliary gas injection port

36: Pressure sensor

37: Processor

38: Temperature sensor

39: Heater

4: Casting device

S10: Steps

S20: Steps

S30: Step

S31: Step

S32: Step

S33: Step

S34: Step

S40: Steps

FIG. 1 is a flow chart of a manufacturing method of foamed metal according to an embodiment of the present invention.

FIG. 2 is a flow chart of an intermediate foaming process of a manufacturing method of foamed metal according to an embodiment of the present invention.

3 is a schematic plan view of an intermediate foaming chamber according to an embodiment of the present invention.

4 is a schematic cross-sectional view of the gas injection foaming furnace, the intermediate foaming chamber and the casting device of the foam metal manufacturing equipment according to an embodiment of the present invention.

FIG. 5 a is a metallographic diagram and a relationship diagram of the diameter/number of pores of a foamed metal of a comparative example of the prior art.

5b to 5e are the metallographic diagrams and the relationship diagrams of the diameter/number of holes of the foamed metal according to the embodiments 1 to 4 of the present invention.

In order to make the above objects, features and characteristics of the present invention more obvious and easy to understand, the relevant embodiments of the present invention are described in detail as follows in conjunction with the drawings.

FIG. 1 is a flow chart of a manufacturing method of foamed metal according to an embodiment of the present invention. The manufacturing method of the foamed metal mainly includes: in the smelting step: performing a smelting process S10, in the gas injection foaming step: performing a gas injection foaming process S20, in the intermediate foaming step: performing an intermediate foaming process S30, And in the casting step: a casting process S40 is performed.

The smelting process S10 utilizes the smelting furnace to smelt the metal material to form a molten metal soup. For example, the smelting furnace can be an induction smelting furnace, which includes an induction coil to melt the metal material to form a molten metal soup. The gas injection foaming process S20 utilizes the gas injection foaming furnace, the gas injection foaming furnace is connected to the smelting furnace, and gas is injected into the molten metal, so that the molten metal is filled with air bubbles generated by the gas to form a foam gold Is a molten soup. For example, the gas injection foaming furnace may include a rotating shaft (eg, above 500 rpm) rotating blades to stir the semi-solid metal molten soup; and a gas injection port for injecting gas into the semi-solid metal molten soup, so as to This foamed metal molten soup is formed. The intermediate foaming process S30 utilizes the intermediate foaming chamber, the intermediate foaming chamber is connected to the gas injection foaming furnace, and controls the working temperature of the foamed metal molten soup to be in the semi-solid temperature range, so that the foamed metal melts The soup is maintained in a semi-solid state until the shape of its internal bubbles gradually converges, forming a target molten soup. The casting process S40 utilizes the casting device. The casting device is connected to the intermediate foaming chamber to solidify the target molten metal into a foamed metal, and the foamed metal is filled with a plurality of incompletely connected holes. For example, the casting device may be a water-cooled mold.

FIG. 2 is a flow chart of an intermediate foaming process of a manufacturing method of foamed metal according to an embodiment of the present invention. The intermediate foaming process includes: in step S31, providing an intermediate foaming chamber, which accommodates the molten metal foam; in step S32 (temperature control step): controlling the working temperature of the molten metal foam to be Semi-solid temperature range; in step S33 (pressure maintaining step): while maintaining the working temperature, the pressure of the foamed metal molten soup is controlled to be a range between normal pressure and 500m bar, when the pressure is less than one When the target pressure value is reached, compensation for the molten metal foam is performed, so that the bearing pressure of the molten metal foam is restored to the target pressure value, so that the molten metal foam can be maintained under pressure; and in step S34 (auxiliary) Gas injection step): when the amount of air bubbles contained in the molten metal foam is less than a preset value, auxiliary gas is injected into the molten metal foam to restore the amount of air bubbles to the preset value to form the Target molten soup.

3 is a schematic plan view of the intermediate foaming chamber of the present invention. The intermediate foaming chamber 3 includes: the outer part 311 is made of alloy steel, and the inner part 312 is made of refractory bricks. The interior 312 has a molten bath inlet 321 and a molten bath outlet 322 . The intermediate foaming chamber 3 further includes a locking member 33 and a rotatable pin 34 for opening or closing the intermediate foaming chamber 3 . 4 is a schematic cross-sectional view of the gas injection foaming furnace, the intermediate foaming chamber and the casting device of the foamed metal manufacturing equipment of the foamed metal manufacturing equipment of the present invention. Please refer to FIG. 4 , the manufacturing equipment of the foamed metal includes the gas injection connected to each other. The foaming furnace 2 and the casting device 4 . The intermediate foaming chamber 3 is arranged and connected between the gas injection foaming furnace 2 and the casting device 4 . The gas injection foaming furnace 2 is connected to a gas supplier 23 , and the gas injection foaming furnace 2 includes a main gas injection port 21 , which is arranged in the interior 22 of the gas injection foaming furnace 2 for injecting the gas supplier 23 The gas is filled in the molten metal of the smelting furnace and the molten metal is filled with bubbles 11 generated by the gas. The molten soup inlet 321 of the intermediate foaming chamber 3 is communicated with the gas injection foaming furnace 2 for receiving the foamed metal molten soup of the gas injection foaming furnace (ie the semi-solid metal molten soup 10 containing the air bubbles 11 ). ). The intermediate foaming chamber 3 includes an auxiliary gas injection port 35 , which is disposed in the interior 312 of the intermediate foaming chamber 3 for assisting the injection of the gas from the gas supplier 23 to the half of the intermediate foaming chamber 3 containing the bubbles 11 . The molten metal 10 is solid, and more bubbles 11 are generated closer to the molten metal outlet 322 (closer to the casting device 4). For example, the injection gas can be nitrogen (N2), air (Air), argon (Ar), etc., and the gas injection flow rate can be more than 10sccm, where sccm is ml/min, which is also a flow unit.

The intermediate foaming chamber 3 is electrically coupled with a foaming control component 30 for completing the intermediate foaming step of the manufacturing method of the foamed metal. The foaming control element 30 of the intermediate foaming chamber 3 includes a temperature sensor 38 and a heater 39 (such as a resistive nickel-chromium wire) connected to the signal, and the temperature sensor 38 is connected to the intermediate foaming chamber The inside 312 of 3 is used to measure the temperature of the molten soup in the intermediate foaming chamber 3, and the heater 39 is used to control the heated temperature of the molten soup. The heater 39 is disposed outside the intermediate foaming chamber 3 311 , and the processor 37 can use the temperature difference between the actual temperature and the preset temperature to control the heater 39 to control the temperature of the semi-solid metal molten soup 10 containing the bubbles 11 within The semi-solid temperature range is between 700 and 900°C (this temperature range is controlled according to the temperature of the semi-solid aluminum alloy melt). The foaming control assembly 30 further includes a flow control valve and a pressure sensor 36 connected with a signal. The pressure sensor 36 is disposed in the interior 312 of the intermediate foaming chamber 3 for measuring the intermediate foaming chamber The molten soup pressure in 3, when the pressure inside 312 of the intermediate foaming chamber 3 is insufficient, the processor 37 can use the pressure difference between the actual withstand pressure and the target pressure value to control the flow control valve 12 to carry out the semi-solid metal melting. The flow of the soup 10 is compensated, so that the foamed metal soup (semi-solid metal molten soup 10 containing air bubbles 11) can be subjected to pressure Maintain (range between normal pressure and 500mbar) (this pressure range is based on the pressure of the semi-solid aluminum metal molten soup). The molten soup outlet 322 of the intermediate foaming chamber 3 is communicated with the casting device 4 for sending the semi-solid metal molten soup 10 (the target molten soup at this time) to the casting device 4 . The foaming control component 30 further includes a timer 30 , which can time the target molten soup to determine the time for solidifying the foamed metal in the casting device 4 .

In this embodiment, the semi-solid metal molten soup may be a semi-solid aluminum alloy molten soup. Finally, by means of a casting device, the target molten liquid passing through the intermediate foaming chamber is solidified into an aluminum foamed metal, and the interior of the aluminum foamed metal is filled with a plurality of incompletely connected holes. The casting device can be matched with, for example, a low pressure casting machine, a continuous casting machine, a vacuum casting machine, a gravity casting machine, etc. FIGS. 5 a to 5 e are metallographic diagrams and relationship diagrams of the diameter/number of holes of the foamed metal of the comparative example of the prior art and the examples 1 to 4 of the present invention. Table 1 is the difference table of the experimental results of the comparative example of the prior art and the foam metal manufacturing method of the embodiments 1 to 4 of the present invention, as follows:

It can be seen from the above-mentioned FIGS. 5 a to 5 e and Table 1 that, compared with the prior art, under the control of temperature and pressure, the porous metal foamed metal pore sizes of the embodiments 1 to 4 of the present invention can be made more consistent, especially if implemented In Examples 3 to 4, the pore shape distribution tends to be narrower, thereby improving the mechanical properties of the porous foamed metal, so that it has better effects such as impact resistance, shielding and thermal insulation; in addition, can simultaneously increase The volume fraction of the pores of the porous foamed metal not only has better mechanical properties, but also has better impact resistance due to its relatively average force when it is impacted by external forces.

Since the intermediate foaming process of the manufacturing method of foamed metal of the present invention can control the temperature and maintain the pressure of the molten metal, and can assist in the injection of gas, the bubbles and the molten metal can be effectively and fully formed. Contact, the bubbles are relatively uniformly distributed in the molten metal foam, thereby improving the uniformity of the pores of the porous metal foam. Accordingly, the metal foam manufacturing method and equipment of the present invention can obtain porous metal foam with better mechanical properties and more uniform density, which is an effective improvement over the current metal foam manufacturing method and equipment.

To sum up, the present invention merely describes the preferred embodiments or examples of the technical means adopted by the present invention to solve the problem, and is not intended to limit the scope of the patent implementation of the present invention. That is, all the equivalent changes and modifications that are consistent with the context of the scope of the patent application of the present invention, or made in accordance with the scope of the patent of the present invention, are all covered by the scope of the patent of the present invention.

10: Metal Molten Soup

11: Bubbles

12: Flow control valve

2: Gas injection foaming furnace

21: Main air injection port

22: Inside

23: Gas supply

3: Intermediate foaming chamber

30: Foaming control components

311: External

312: Internal

32: Timer

321: molten soup entrance

322: molten soup outlet

35: Auxiliary gas injection port

36: Pressure sensor

37: Processor

38: Temperature sensor

39: Heater

4: Casting device

Claims (8)

A manufacturing method of foamed metal, comprising the following steps: a smelting step, melting a metal material to form a molten metal; a gas injection foaming step, injecting gas into the molten metal, so that the molten metal is filled with the gas The bubbles generated form a foamed metal molten soup; an intermediate foaming step controls the working temperature of the foamed metal molten soup in its semi-solid temperature range, so that the foamed metal molten soup is maintained in a semi-solid state until its interior The shape of the bubbles tends to be consistent gradually, forming a target molten soup; and a casting step, solidifying the target molten soup into a foamed metal, and the foam metal is filled with a plurality of incompletely connected holes; wherein the intermediate foaming step is in While maintaining the working temperature, the pressure of the foamed metal molten soup is controlled to be in the range of normal pressure to 500 mbar; and in the intermediate foaming step, when the pressure is less than a target pressure value, the The foamed metal molten soup is compensated to restore the pressure of the foamed metal molten soup to the target pressure value. The method for manufacturing foamed metal as described in claim 1 of the claimed scope, wherein in the intermediate foaming step, when the amount of air bubbles contained in the molten metal of foam is less than a predetermined value, auxiliary gas is injected into The foamed metal melts and restores the bubble amount to the preset value. The method for manufacturing foamed metal as described in claim 1, wherein in the intermediate foaming step, when the metal material is an aluminum alloy, the working temperature of the molten metal of the foam is controlled at its semi-solid temperature The interval is 700~900℃. The method for manufacturing foamed metal as described in item 2 of the claimed scope, wherein in the intermediate foaming step, when the metal material is an aluminum alloy, the working temperature of the foamed metal solution is controlled to be in the semi-solid temperature range 700~900℃. A manufacturing equipment for foamed metal, comprising a gas injection foaming furnace and a casting device that communicate with each other, and the gas injection foaming furnace is connected with a gas supplier, characterized in that the manufacturing equipment for foamed metal further comprises a The intermediate foaming chamber is arranged between the gas injection foaming furnace and the casting device, and the intermediate foaming chamber is electrically coupled with a foaming chamber The control component is used to complete the intermediate foaming step of the manufacturing method of foamed metal according to claim 1 to 4. The manufacturing equipment for foamed metal as described in claim 5, wherein the foaming control component comprises a heater and a temperature sensor connected with a signal, and the temperature sensor is used for measuring the intermediate foaming chamber The temperature of the molten soup, the heater is used to control the heating temperature of the molten soup. The manufacturing equipment for foamed metal as described in claim 5 or 6, wherein the foam control element further comprises a flow control valve and a pressure sensor connected with a signal, and the pressure sensor is used to measure the The pressure of the molten soup in the intermediate foaming chamber, and the flow control valve is used to control the flow compensation of the molten soup. The manufacturing equipment for foamed metal as described in claim 5 or 6 of the claimed scope, wherein the foaming control component further comprises a timer.

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