阅读说明：本技术 一种层级密度泡沫铝生产设备及方法 (Equipment and method for producing layered density foamed aluminum ) 是由 薛有为 于 2021-07-27 设计创作，主要内容包括：本发明公开了一种层级密度泡沫铝生产设备及方法。生产设备包括螺杆和套筒,套筒上设有增稠铝液上料口,第一发泡剂上料装置和第二发泡剂上料装置,螺杆设置于套筒内,螺杆位于套筒前段,套筒前端设有发泡段,增稠铝液上料口设置于套筒前端上部,第一发泡剂上料装置设置于增稠铝液上料口下游,第二发泡剂上料装置设置于第一发泡剂上料装置之后。生产方法包括发泡,挤压与成型；将铝溶液加入套筒对铝液进行搅拌和推进,套筒前段设有发泡段,加入发泡剂的铝液在发泡段完成发泡、膨胀,接着进入到发泡仓。本发明使铝液发泡后搅碎生成更细小的气泡,改善了泡沫铝的成型性能,提高发泡均匀度和成品率,精密可控的生产出不同密度梯度的泡沫铝板。(The invention discloses a device and a method for producing layered density foamed aluminum. Production facility includes screw rod and sleeve, is equipped with thickening aluminium liquid feed opening on the sleeve, first foaming agent loading attachment and second foaming agent loading attachment, and the screw rod sets up in the sleeve, and the screw rod is located the sleeve anterior segment, and the sleeve front end is equipped with the foaming section, and thickening aluminium liquid feed opening sets up in sleeve front end upper portion, and first foaming agent loading attachment sets up in thickening aluminium liquid feed opening low reaches, and second foaming agent loading attachment sets up behind first foaming agent loading attachment. The production method comprises foaming, extruding and forming; adding an aluminum solution into the sleeve to stir and propel the aluminum liquid, wherein the front section of the sleeve is provided with a foaming section, and the aluminum liquid added with the foaming agent is foamed and expanded in the foaming section and then enters a foaming bin. The invention ensures that the aluminum liquid is crushed after foaming to generate finer bubbles, improves the forming performance of the foamed aluminum, improves the foaming uniformity and the yield, and produces the foamed aluminum plates with different density gradients in a precise and controllable way.)

1. A layer density foamed aluminum production facility characterized by comprising:

the device comprises a screw, a sleeve, a thickened aluminum liquid feeding port, a first foaming agent feeding device, a second foaming agent feeding device, a foaming bin, an extrusion plate, a forming die and a heating and heat-insulating device;

the sleeve is a hollow cylinder, and the screw is arranged in the sleeve; the screw is used for stirring and propelling the aluminum liquid through rotation; the outlet at the rear end of the sleeve is connected with the foaming bin; the thickened aluminum liquid feeding port, the first foaming agent feeding device and the second foaming agent feeding device are arranged above the sleeve and are sequentially arranged from the front end to the rear end of the sleeve; the thickened aluminum liquid feeding port is arranged at the upper part of the front end of the sleeve, the first foaming agent feeding device is arranged at the downstream of the thickened aluminum liquid feeding port, the second foaming agent feeding device is arranged behind the first foaming agent feeding device, and the outlet of the foaming section of the sleeve 2 is connected with the foaming bin;

the lower part of the foaming bin is provided with a melt extrusion nozzle; an extrusion plate is arranged in the foaming bin and is used for extruding the melt aluminum liquid which is foamed in the foaming bin 6 through a melt extrusion nozzle;

the outer wall of the sleeve is provided with a heating and heat-preserving device, and the foaming bin is provided with a water pipe cooling device and a heating and heat-preserving device.

2. The apparatus for producing graded density foamed aluminum according to claim 1, wherein:

two ends of the extrusion plate are connected to sliding rails in a sliding mode, the sliding rails are fixed to the upper portion of the inner wall of the foaming bin, and the upper portion of the extrusion plate is connected with a cylinder; the cylinder is used for driving the extrusion plate to move up and down along the slide rail, and the melt aluminum liquid which completes foaming in the foaming bin is extruded out through the melt extrusion nozzle.

3. The apparatus for producing graded density foamed aluminum according to claim 1, wherein:

the forming die comprises a steel die body, and a forming groove and a heating inductance coil are arranged on the steel die body;

a protective shell is arranged outside the steel mold body, and the heating inductance coil is positioned between the protective shell and the steel mold body; the forming groove is provided with a ceramic fiber baffle which is rotatably connected with the forming groove, and the ceramic fiber baffle can be rotatably held in a first position in an erected mode or can be held in a second position in a falling mode; the molding groove is communicated when rotating to the first position, and the molding groove is divided into two spaces of a left molding groove and a right molding groove when rotating to the second position.

4. A graded density foamed aluminum production facility as claimed in claim 3 wherein:

the heating inductance coil comprises a left heating inductance coil and a right heating inductance coil which are respectively arranged near the left forming groove and the right forming groove.

5. A graded density foamed aluminum production facility as claimed in claim 3 wherein:

the steel mould body is provided with a safety stop gate, and the ceramic fiber baffle can rotate to a second position when the safety stop gate is opened; the safety door when closed blocks the ceramic fiber barrier from falling down so that it can only remain in one position.

6. The apparatus for producing graded density foamed aluminum according to claim 1, wherein:

the forming die comprises a steel die body, and a forming groove, a left heating inductance coil, a middle heating inductance coil and a right heating inductance coil are arranged on the steel die body;

the forming groove is provided with a first ceramic fiber block and a second ceramic fiber block, and the first ceramic fiber block and the second ceramic fiber block are rotatably connected with the forming groove; each of the first ceramic fiber block and the second ceramic fiber block can rotate, erect and keep at a first position, or fall and keep at a second position, and the forming grooves are communicated when the first ceramic fiber block and the second ceramic fiber block rotate to the first position, and the forming grooves are divided into two spaces when the second ceramic fiber block and the first ceramic fiber block rotate to the second position; when the first ceramic fiber block and the second ceramic fiber block are kept at the second position, the forming groove is divided into a left forming groove, a middle forming groove and a right forming groove;

the left heating inductance coil, the middle heating inductance coil and the right heating inductance coil are respectively arranged at the adjacent positions of the left forming groove, the middle forming groove and the right forming groove.

7. The apparatus for producing graded density foamed aluminum according to claim 6, wherein:

the steel mould body is provided with a first safety stop gate and a second safety stop gate; when the first safety stop door is opened, the first ceramic fiber baffle can rotate to a second position; the first ceramic fiber baffle can only be kept in one position when the first safety stop is closed; the second ceramic fiber baffle can rotate to a second position when the second safety stop door is opened; the second ceramic fiber flapper can only remain in one position when the second safety shutter is closed.

8. A method for producing a layered density foamed aluminum by using the production apparatus according to any one of claims 1 to 5, comprising:

preheating the hierarchical density foamed aluminum production equipment, wherein the preheating temperature is 300-340 ℃;

smelting an aluminum raw material to 750-780 ℃, putting the aluminum raw material and the tackifier into a thickened aluminum liquid feeding port together, entering a sleeve, and stirring and propelling the aluminum liquid through the rotation of a screw;

adding a foaming agent through a first foaming agent feeding device, and continuously stirring through a screw, wherein the foaming stirring time is 1-2 min;

controlling the temperature by a heating device, wherein the temperature of a stirring area is 670-690 ℃, the adding temperature of a foaming agent is 670-690 ℃, the temperatures of a foaming section and a foaming bin are 600-660 ℃, and the temperature of a mold outlet is 490-510 ℃;

and the aluminum liquid added with the foaming agent is foamed and expanded in a foaming section, is gradually cooled to be in a semi-solid state, then enters a foaming chamber for heat preservation, is extruded out, enters a forming die body 10 to generate a required shape, and is sequentially extruded to prepare the foamed aluminum plate with the gradient level by the foamed aluminum liquid with different densities.

9. The method of claim 8, wherein:

the method for manufacturing the hierarchical gradient foamed aluminum plate by sequentially extruding foamed aluminum liquids with different densities comprises the following steps:

a forming groove 102 surrounded by a right heating inductance coil 104 of the forming die receives the low-density gradient foamed aluminum solution, the outlet temperature of the forming groove is 490-510 ℃, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the forming groove in a semi-solid state;

a forming groove 102 surrounded by a left heating inductance coil 103 of the forming die receives the foamed aluminum solution with high density gradient;

opening the ceramic fiber baffle 106, then quickly closing the safety baffle 107, and cooling and pressurizing the foamed aluminum solution with different densities in the forming tank 102, wherein the temperature treatment mode is cooling to the solidification temperature; the high density gradient foamed aluminum solution and the low density gradient foamed aluminum semi-solid are connected together, and two foamed aluminum plates with different density gradients are formed.

10. The method of claim 8, wherein:

the tackifier is any one of MnO2, SiC and Al2O3, and the addition content is 2%.

11. The method of claim 8, wherein:

the foaming agent is any one of TiH2, CaH2 or Ni/TiH2 composite powder, and the amount of the foaming agent added is 1.5 percent of the mass of the aluminum raw material.

12. A method for producing three-layer density foamed aluminium by using the production equipment of any one of claims 6 to 7, which comprises:

preheating the hierarchical density foamed aluminum production equipment, wherein the preheating temperature is 300-340 ℃;

smelting an aluminum raw material to 750-780 ℃, putting the aluminum raw material and the tackifier into a thickened aluminum liquid feeding port together, entering a sleeve, and stirring and propelling the aluminum liquid through the rotation of a screw;

adding a foaming agent through a first foaming agent feeding device, and continuously stirring through a screw, wherein the foaming stirring time is 1-2 min;

controlling the temperature by a heating device, wherein the temperature of a stirring area is 670-690 ℃, the adding temperature of a foaming agent is 670-690 ℃, the temperatures of a foaming section and a foaming bin are 600-660 ℃, and the temperature of a mold outlet is 490-510 ℃;

foaming and expanding the aluminum liquid added with the foaming agent in a foaming section, gradually cooling the aluminum liquid to a semi-solid state, then feeding the aluminum liquid into a foaming bin for heat preservation for 2-4 min, extruding the aluminum liquid, and feeding the extruded aluminum liquid into a forming die body to generate a required shape;

three foamed aluminum liquids with different densities are extruded in sequence to manufacture the foamed aluminum plate with the gradient level.

13. The method of claim 12, wherein:

the step-gradient foamed aluminum plate manufactured by sequentially extruding three kinds of foamed aluminum liquids with different densities specifically comprises the following steps:

the left forming groove of the forming die receives the low-density gradient foamed aluminum solution, the outlet temperature of the left forming groove is 490-510 ℃, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the left forming groove in a semi-solid state;

the forming groove receives the foamed aluminum solution with medium density gradient, the outlet temperature of the forming groove is 490-510 ℃, the first ceramic fiber baffle is opened, then the first safety stop door is closed rapidly, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the forming groove in a semi-solid state;

the right forming groove receives the foamed aluminum solution with high density gradient, the second ceramic fiber baffle is opened, then the safety stop door is closed rapidly, and then the foamed aluminum solution with different density in the forming groove is cooled and pressurized, wherein the temperature processing mode is cooling to the solidification temperature; the foamed aluminum solution with high, medium and low density gradients are connected together, namely a three-layer foamed aluminum plate with different density gradients is formed.

Technical Field

The invention belongs to the technical field of foamed aluminum production equipment and processes, and particularly relates to equipment and a method for producing foamed aluminum with a layered density.

Background

The foamed aluminum is prepared by adding a foaming agent into pure aluminum or aluminum alloy and then performing a foaming process, and has the characteristics of metal and bubbles. The foamed aluminum is a multifunctional material with high porosity, has the composite characteristics of light weight, high strength and toughness, crashworthiness, high specific strength, high specific rigidity, flame retardance, heat insulation, vibration and noise reduction, corrosion resistance and electromagnetic shielding, and is widely applied to the fields of electronics, communication, metallurgy, chemical industry, construction, transportation, aerospace and the like.

The energy absorption of the foamed aluminum has good rate strain characteristics, namely the higher the strain rate is, the higher the absorbing capacity of the foamed aluminum per unit volume is, and the highest absorbing capacity can reach 8-30J/cm 3. Currently, automobile companies such as Benz, BMW and Honda have used foamed aluminum materials for automobile anti-collision beams, A columns, B columns and the like for anti-collision and energy absorption of automobile bodies.

The gradient foamed aluminum is a foamed aluminum structure with continuously changed density, pore size and components in a certain dimension direction of the foamed aluminum, overcomes the defects of the traditional homogeneous foamed aluminum material, can use a low porosity area as a bearing, and realizes the functional characteristics of a high porosity area, so the gradient foamed aluminum is an advanced structure-function integrated material structure. At present, the preparation method of the gradient foamed aluminum comprises a seepage casting method, an occupying body sintering method, a stirring friction processing method, a chemical milling method and the like.

The seepage casting method is characterized in that aluminum ingots and NaCl are used as raw materials, firstly, the NaCl is placed in a mold, a NaCl blank is prepared by a press, the volume fraction of the NaCl in the blank is controlled by controlling pressure, then the aluminum ingots and the blanks with different NaCl volume fractions are stacked together according to a certain sequence and placed in seepage casting equipment, under the action of air pressure, a melt of the aluminum ingots is injected into pores of the NaCl blank and is placed in water after being cooled to room temperature, and the NaCl in the blanks is dissolved in the water, so that the gradient foamed aluminum structure is prepared.

The space occupying body sintering method is characterized in that aluminum powder and a space occupying body (NaCl) are used as raw materials, the aluminum powder, the space occupying body (different particle sizes and different mass ratios) and a small amount of tackifier are fully mixed, different mixed powder is laid in a die according to a certain sequence, a press is utilized to carry out densification treatment on various blanks, then the blanks are placed in water, wherein the space occupying body is dissolved into the water, and finally high-temperature sintering is carried out to complete the preparation of the gradient foamed aluminum structure.

The friction stir processing method is characterized in that an aluminum plate is used as a raw material, titanium hydride is used as a foaming agent, the titanium hydride is placed between two aluminum plates, the two aluminum plates are connected together through friction stir welding, the titanium hydride is uniformly distributed in the aluminum alloy in the process, blanks with different titanium hydride contents are prepared by the same method, then the blanks are discharged in a certain sequence, the blanks are connected together through the friction stir welding, and finally, the gradient foamed aluminum structure is prepared through high-temperature foaming.

The chemical milling method is to immerse the prepared open-cell foamed aluminum in NaOH or HCI solution, and control the erosion time of the foamed aluminum in the solution by controlling the liquid level height of the NaOH or HCI solution, thereby obtaining the gradient foamed aluminum structure.

At present, the preparation methods of the gradient foamed aluminum have defects, a press is needed to prepare a blank in the preparation processes of the seepage casting method and the occupying body sintering method, the external dimension of the prepared gradient foamed aluminum is limited by the tonnage and the table size of the press, and a water dissolving container which is matched with the press is needed to be specially equipped, so that the operation is complex, the dies are various, and the cost is high. In the process of the friction stir processing method, a large amount of friction stir processes are needed, which comprise foaming agent dispersion and connection between blanks with different characteristics, and high-temperature device treatment is needed, so that the problems of low processing efficiency and high cost exist; acid, alkali and other solutions are used in the chemical milling process, and a special device is needed for completion, so that the environment friendliness is poor, and the cost is high.

Disclosure of Invention

Aiming at the defects of the existing gradient foamed aluminum generation equipment and generation process, the invention aims to provide equipment and a method for producing foamed aluminum with hierarchical density.

In a first aspect, an embodiment of the present invention provides a device for producing layered density foamed aluminum, including:

the device comprises a screw 1, a sleeve 2, a thickened aluminum liquid feeding port 3, a first foaming agent feeding device 4, a second foaming agent feeding device 5, a foaming bin 6, an extrusion plate 8, a forming die 10 and a heating and heat-insulating device;

the sleeve 2 is a hollow cylinder, and the screw rod 1 is arranged inside the sleeve 2; the screw 1 is used for stirring and propelling the aluminum liquid through rotation; the outlet at the rear end of the sleeve 2 is connected with a foaming bin 6; a thickened aluminum liquid feeding port 3, a first foaming agent feeding device 4 and a second foaming agent feeding device 5 are arranged above the sleeve 2 and are sequentially arranged from the front end to the rear end of the sleeve 2; the thickened aluminum liquid feeding port 3 is arranged at the upper part of the front end of the sleeve 2, the first foaming agent feeding device 4 is arranged at the downstream of the thickened aluminum liquid feeding port 3, the second foaming agent feeding device 5 is arranged behind the first foaming agent feeding device 4, and the outlet of the foaming section of the sleeve 2 is connected with the foaming bin 6;

the lower part of the foaming bin 6 is provided with a melt extrusion nozzle 7; an extrusion plate 8 is arranged in the foaming bin 6 and is used for extruding the melt aluminum liquid which is foamed in the foaming bin 6 through a melt extrusion nozzle 7;

the outer wall of the sleeve 2 is provided with a heating and heat-preserving device, and the foaming bin 6 is provided with a water pipe cooling device and a heating and heat-preserving device.

Furthermore, two ends of the extrusion plate 8 are slidably connected to slide rails, the slide rails are fixed on the upper part of the inner wall of the foaming bin 6, and the upper part of the extrusion plate is connected with a cylinder 9; the cylinder 9 is used for driving the extrusion plate to move up and down along the slide rail, and the melt aluminum liquid which completes foaming in the foaming bin 6 is extruded out through the melt extrusion nozzle 7.

In one possible embodiment, the forming mold 10 includes a steel mold body 101, and the steel mold body 101 is provided with a forming groove 102 and a heating inductor;

a protective shell 105 is arranged outside the steel mold body 101, and a heating inductance coil is positioned between the protective shell 105 and the steel mold body 101; the forming groove 102 is provided with a ceramic fiber baffle 106, the ceramic fiber baffle 106 is rotatably connected with the forming groove 102, and the ceramic fiber baffle 106 can be rotatably erected and kept at a first position or fallen and kept at a second position; the molding groove 102 is communicated when rotated to the first position, and the molding groove 102 is divided into two spaces when rotated to the second position.

Further, the heating inductance coil comprises a left heating inductance coil 103 and a right heating inductance coil 104;

further, a safety door 107 is installed on the steel mold body 101, and when the safety door 107 is opened, the ceramic fiber baffle 106 can rotate to a second position; the ceramic fiber flap 106 can only remain in one position when the safety door 107 is closed.

In one possible embodiment, the forming mold 10 includes a steel mold body 101, and a forming groove 102, a first heating inductor, a second heating inductor and a third heating inductor are provided on the steel mold body 101;

the forming groove 102 is provided with a first ceramic fiber block and a second ceramic fiber block, and the first ceramic fiber block and the second ceramic fiber block are rotatably connected with the forming groove 102; each of the first and second ceramic fiber blocks may be rotatably held upright in a first position or may be held down in a second position, and the forming groove 102 is communicated when rotated to the first position, and the forming groove 102 is divided into two spaces when rotated to the second position.

Further, the heating induction coil comprises a first heating induction coil, a second heating induction coil and a third heating coil;

further, the steel mold body 101 is provided with a first safety stop and a second safety stop; when the first safety stop door is opened, the first ceramic fiber baffle can rotate to a second position; the first ceramic fiber baffle can only be kept in one position when the first safety stop is closed; the second ceramic fiber baffle can rotate to a second position when the second safety stop door is opened; the second ceramic fiber flapper can only remain in one position when the second safety shutter is closed.

In a second aspect, an embodiment of the present invention provides a method for producing a hierarchical density foamed aluminum by using the production apparatus provided in the first aspect, including:

preheating the hierarchical density foamed aluminum production equipment, wherein the preheating temperature is 300-340 ℃;

smelting an aluminum raw material to 750-780 ℃, putting the aluminum raw material and the tackifier into a thickened aluminum liquid feeding port together, entering a sleeve, and stirring and propelling the aluminum liquid through the rotation of a screw;

adding a foaming agent through a first foaming agent feeding device, and continuously stirring through a screw, wherein the foaming stirring time is 1-2 min;

controlling the temperature by a heating device, wherein the temperature of a stirring area is 670-690 ℃, the adding temperature of a foaming agent is 670-690 ℃, the temperatures of a foaming section and a foaming bin are 600-660 ℃, and the temperature of a mold outlet is 490-510 ℃;

and the aluminum liquid added with the foaming agent is foamed and expanded in a foaming section, is gradually cooled to be in a semi-solid state, then enters a foaming chamber for heat preservation, is extruded out, enters a forming die body 10 to generate a required shape, and is sequentially extruded to prepare the foamed aluminum plate with the gradient level by the foamed aluminum liquid with different densities.

Further, the step gradient foamed aluminum plate manufactured by sequentially extruding foamed aluminum liquids with different densities comprises the following steps:

a forming groove 102 surrounded by a right heating inductance coil 104 of the forming die receives the low-density gradient foamed aluminum solution, the outlet temperature of the forming groove is 490-510 ℃, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the forming groove in a semi-solid state;

a forming groove 102 surrounded by a left heating inductance coil 103 of the forming die receives the foamed aluminum solution with high density gradient;

opening the ceramic fiber baffle 106, then quickly closing the safety baffle 107, and cooling and pressurizing the foamed aluminum solution with different densities in the forming tank 102, wherein the temperature treatment mode is cooling to the solidification temperature; the high density gradient foamed aluminum solution and the low density gradient foamed aluminum semi-solid are connected together, and two foamed aluminum plates with different density gradients are formed.

Further, the tackifier is any one of MnO2, SiC and Al2O3, and the adding content is 2%;

furthermore, the foaming agent is any one of TiH2, CaH2 or Ni/TiH2 composite powder, and the amount of the foaming agent added is 1.5 percent of the mass of the aluminum raw material.

In one possible embodiment, the method for producing the three-layer density gradient foamed aluminum plate by using the production equipment provided by the first aspect comprises the following steps:

preheating the hierarchical density foamed aluminum production equipment, wherein the preheating temperature is 300-340 ℃;

smelting an aluminum raw material to 750-780 ℃, putting the aluminum raw material and the tackifier into a thickened aluminum liquid feeding port together, entering a sleeve, and stirring and propelling the aluminum liquid through the rotation of a screw;

adding a foaming agent through a first foaming agent feeding device, and continuously stirring through a screw, wherein the foaming stirring time is 1-2 min;

controlling the temperature by a heating device, wherein the temperature of a stirring area is 670-690 ℃, the adding temperature of a foaming agent is 670-690 ℃, the temperatures of a foaming section and a foaming bin are 600-660 ℃, and the temperature of a mold outlet is 490-510 ℃;

foaming and expanding the aluminum liquid added with the foaming agent in a foaming section, gradually cooling the aluminum liquid to a semi-solid state, then entering a foaming bin for heat preservation, wherein the heat preservation time of the foaming bin is 2-4 min, extruding the aluminum liquid, and entering a forming die body 10 to generate a required shape;

the method for manufacturing the foamed aluminum plate with the gradient levels by sequentially extruding three foamed aluminum liquids with different densities comprises the following steps:

the left forming groove of the forming die receives the low-density gradient foamed aluminum solution, the outlet temperature of the left forming groove is 490-510 ℃, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the left forming groove in a semi-solid state;

the forming groove receives the foamed aluminum solution with medium density gradient, the outlet temperature of the forming groove is 490-510 ℃, the first ceramic fiber baffle is opened, then the first safety stop door is closed rapidly, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the forming groove in a semi-solid state;

the right forming groove receives the foamed aluminum solution with high density gradient, the second ceramic fiber baffle is opened, then the safety stop door is closed rapidly, and then the foamed aluminum solution with different density in the forming groove is cooled and pressurized, wherein the temperature processing mode is cooling to the solidification temperature; the foamed aluminum solution with high, medium and low density gradients are connected together, namely a three-layer foamed aluminum plate with different density gradients is formed.

Compared with the prior art, the invention uses the screw rod to crush the aluminum liquid after foaming to generate finer bubbles, thereby improving the forming performance of the foamed aluminum, improving the foaming uniformity and improving the yield; and the equipment has the characteristic of continuous production, is easy to quickly form the foamed aluminum plates with different grades, and has the advantages of high efficiency, low cost and high performance.

Drawings

FIG. 1 is a schematic view of a production apparatus for a graded gradient density foamed aluminum according to an example;

FIG. 2 is a cross-sectional view of an embodiment molding die;

FIG. 3 is a schematic view of a ceramic fiber baffle blocking two forming grooves on the left and right of the forming mold according to the embodiment;

FIG. 4 is a schematic view showing the ceramic fiber shutter of the molding die of the second embodiment being opened and the safety shutter being opened;

FIG. 5 is a schematic view of a second embodiment of a forming die with the ceramic fiber dam open and the safety dam closed;

FIG. 6 is a rear view of a molding die according to the second embodiment;

FIG. 7 is a schematic view of a production apparatus for producing a three-stage gradient density foamed aluminum according to example four;

FIG. 8 is a schematic view of a four-stage three-stage forming die structure according to an embodiment;

FIG. 9 is a schematic view of an example four three level forming die with a single ceramic fiber dam open;

fig. 10 is a schematic view of a four-and three-level forming mold according to an embodiment.

Detailed Description

The present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example one

As shown in fig. 1, the apparatus for producing foamed aluminum with a hierarchical density provided in this embodiment includes: the device comprises a screw rod 1, a sleeve 2, a thickened aluminum liquid feeding port 3, a first foaming agent feeding device 4, a second foaming agent feeding device 5, a foaming bin 6, an extrusion plate 8, a cylinder 9, a forming die 10 and a heating and heat-insulating device. The sleeve 2 is a hollow cylinder, and the screw 1 is arranged in the front end of the hollow cylinder, so that the sleeve 2 forms a foaming section; the screw 1 is used for stirring and propelling the aluminum liquid through rotation; the rear end outlet of the sleeve 2 is connected with the foaming bin 6, and the stirred aluminum liquid enters the foaming bin 6 through the rear end outlet; a thickened aluminum liquid feeding port 3, a first foaming agent feeding device 4 and a second foaming agent feeding device 5 are arranged above the sleeve 2 and are sequentially arranged from the front end to the rear end of the sleeve 2; the thickened aluminum liquid feeding port 3 is arranged at the upper part of the front end of the sleeve 2, the first foaming agent feeding device 4 is arranged at the lower part of the thickened aluminum liquid feeding port 3, the second foaming agent feeding device 5 is arranged behind the first foaming agent feeding device 4, and the outlet of the foaming section of the sleeve 2 is connected with the foaming bin 6. The lower part of the foaming bin 6 is provided with a melt extrusion nozzle 7; the foaming device is characterized in that an extrusion plate 8 is arranged in the foaming bin 6, two ends of the extrusion plate 8 are connected to slide rails in a sliding mode, the slide rails are fixed to the upper portion of the inner wall of the foaming bin 6, the upper portion of the extrusion plate is connected with a cylinder 9, the extrusion plate is driven to move up and down along the slide rails through telescopic action of the control cylinder 9, and melt aluminum liquid which is used for completing foaming in the foaming bin 6 is extruded through a melt extrusion nozzle 7.

The outer wall of the sleeve 2 is provided with a heating and heat-preserving device, and the foaming bin 6 is provided with a water pipe cooling device and a heating and heat-preserving device. The heat capacity of the electric heating device is more than 750 ℃ at the maximum temperature, and the temperature control precision is within +/-5 ℃. The temperature in the foaming section is controlled to be semi-solid temperature, the temperature from the foaming bin to the outlet of the foamed aluminum forming die is controlled to be semi-solid temperature, and the low-density gradient aluminum liquid entering the special die can be at the semi-solid temperature or close to the solidification temperature.

The working process of the hierarchical density foamed aluminum production equipment provided by the embodiment comprises three processes of foaming, extruding and molding, and specifically comprises the following steps:

firstly, preheating equipment, wherein the preheating temperature is 300-340 ℃, then increasing the temperature of aluminum liquid to 750-780 ℃, adding the aluminum liquid and a tackifier into a thickened aluminum liquid feeding port 3, entering a sleeve 2, and stirring and propelling the aluminum liquid through the rotation of a screw 1; adding a foaming agent through a first foaming agent feeding device 4, continuously stirring through a screw rod 1, controlling the temperature through a heating device, wherein the temperature of a stirring area is 670-690 ℃, the temperature of a foaming section and a foaming bin is 600-660 ℃, and the outlet of a melt extrusion nozzle 7 is 490-510 ℃; the rotating speed of the screw rod 1 can be controlled to ensure that the aluminum liquid can be crushed into fine bubbles after foaming, the density of the aluminum liquid is changed, the foaming of the aluminum liquid is more uniform, and the above process is a process for producing a low-density gradient foamed aluminum solution.

The second foaming agent feeding device 5 is a feeding port for supplementing the foaming agent for generating the high-density gradient foamed aluminum solution. In an alternative embodiment, the specific manner of producing the high density aluminum foam solution is: firstly, a first foaming agent is added through the first foaming agent feeding device 4, then the first foaming agent is stirred by the screw rod 1 and pushed to the lower area of the second foaming agent feeding device 5 (namely the rear part of the second foaming agent feeding device 5), and then a second foaming agent is added through the second foaming agent feeding device 5, and meanwhile, the second foaming agent is continuously stirred by the screw rod 1 and pushed into the foaming bin 6. The high-density gradient foamed aluminum is produced through two foaming and stirring processes.

In this embodiment, the specific density in the low-density gradient foamed aluminum solution can be determined by the amount of the foaming agent added through the first foaming agent feeding device 4 and the rotation speed of the screw 1, i.e. the density of the low-density gradient foamed aluminum solution is microscopically regulated.

Embodiment one the forming die 10 in the hierarchical density foamed aluminum production apparatus may be designed in the following structure. In the second embodiment, the forming mold 10 includes a steel mold body 101, a forming groove 102, a left heating inductor 103 and a right heating inductor 104 are disposed on the steel mold body 101, a protective shell 105 is disposed around an outer portion of the steel mold body 101, and the left heating inductor 103 and the right heating inductor 104 are located between the protective shell 105 and the steel mold body 101. Between the molding grooves 102, a ceramic fiber baffle 106 is installed, and the ceramic fiber baffle 106 is electrically controlled and can rotate upwards to communicate the molding grooves 102. The steel mold body 101 is provided with a safety door 107, and the safety door 107 can be controlled by a manual or electric mechanism, so that the opening and closing of the safety door 107 can be controlled outside.

In a possible implementation manner, the left heating inductor 103 and the right heating inductor 104 may also be installed at the innermost layer of the forming die 10.

The aluminum liquid added with the foaming agent is foamed and expanded in a foaming section and is gradually cooled to be in a semi-solid state, then the aluminum liquid enters a foaming bin 6 for heat preservation and extrusion, the aluminum liquid enters a forming die 10 to generate a required shape, and the foamed aluminum plate with two different level gradients is manufactured according to the foamed aluminum liquid with different extruded densities.

EXAMPLE III

The invention provides a production process of layered density foamed aluminum, which comprises three processes of foaming, extruding and molding, and comprises the following specific steps:

(1) preparing raw materials, wherein the aluminum raw material in the embodiment is A356 aluminum alloy or pure aluminum;

(2) preheating the hierarchical density foamed aluminum production equipment, wherein the preheating temperature is 300-340 ℃;

(3) smelting aluminum alloy to 750-780 ℃, putting the aluminum alloy and the tackifier into a thickened aluminum liquid feeding port together, entering a sleeve, and stirring and propelling the aluminum liquid through the rotation of a screw; and adding the foaming agent through a first foaming agent feeding device, and continuously stirring through a screw, wherein the foaming stirring time is 1-2 min. The temperature is controlled by a heating device, three sections of control are adopted, the temperature of a stirring area is 670-690 ℃, the adding temperature of a foaming agent is 670-690 ℃, the temperature of a foaming section and a foaming bin is 600-660 ℃, and the temperature of a mold outlet, namely a melt extrusion nozzle 7, is 490-510 ℃; the tackifier can be any one of MnO2, SiC and Al2O3, and the addition content is 2%. The foaming agent can be any one of TiH2, CaH2 or Ni/TiH2 composite powder, the amount of the foaming agent added is 1.5 percent of the mass of the aluminum raw material, and the aluminum raw material is A356 aluminum alloy or pure aluminum.

(4) And the aluminum liquid added with the foaming agent is foamed and expanded in a foaming section, is gradually cooled to be in a semi-solid state, then enters a foaming bin for heat preservation, is extruded out, and enters a forming die, wherein the heat preservation time of the foaming bin is 2-4 min.

(5) Firstly, a forming groove 102 surrounded by a right heating inductance coil 104 of a forming die receives a low-density gradient foamed aluminum solution, the outlet temperature of the forming groove is 490-510 ℃, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the forming groove in a semi-solid state; thereafter, a forming groove 102 surrounded by a left heating inductance coil 103 of the forming die receives the foamed aluminum solution with high density gradient; finally, opening the ceramic fiber baffle 106 in an electric control mode, rapidly closing the safety baffle 107 in an electric control mode, and cooling and pressurizing the foamed aluminum solutions with different densities in the forming groove 102, wherein the temperature treatment mode is cooling to the solidification temperature; the high density gradient foamed aluminum solution and the low density gradient foamed aluminum semi-solid are connected together, and two foamed aluminum plates with different density gradients are formed.

Foamed aluminum panels of different level gradients. The specific density of the foamed aluminum solution depends on the actual bubble density of the aluminum solution in the stirring area and the foaming area, and the specific temperature can be adjusted according to the actual change of the foamed aluminum solution in the whole process, and the temperature is only the exemplified temperature of the invention.

Example four

As shown in fig. 7, three-level density gradient foamed aluminum plates were produced by placing three-level density gradient foamed aluminum solutions into a three-level mating mold 11, and the operation method was the same as that of the two-level density gradient foamed aluminum plate produced in the third example. Wherein, the three-level matched forming die and the two-level forming die have the same structure and are only provided with one more forming groove.

Fig. 8, 9 and 10 show that the forming mold for producing the three-layer-level density gradient foamed aluminum plate comprises a three-layer steel mold body 11, wherein a forming groove and a heating inductance coil are arranged on the three-layer steel mold body 11, a protective shell 115 is arranged around the three-layer steel mold body 11, and the heating inductance coil is positioned between the protective shell 115 and the three-layer steel mold body 11. Ceramic fiber baffles 116 and 1161 are arranged between the forming grooves, and the ceramic fiber baffles 116 and 1161 are electrically controlled and can rotate upwards to communicate the forming grooves. The steel mold body is provided with a safety shutter 117, and a safety shutter 1171 can be controlled by a manual or electric mechanism, and the opening and closing of the safety shutters 117 and 1171 are controlled outside.

The process flow for producing the three-layer density gradient foamed aluminum plate comprises the following steps:

(1) preparing raw materials, wherein the aluminum raw material is A356 alloy or pure aluminum;

(2) preheating equipment, wherein the preheating temperature is 300-340 ℃;

(3) smelting aluminum alloy to 750-780 ℃, putting the aluminum alloy and the tackifier into a thickened aluminum liquid feeding port together, entering a sleeve, and stirring and propelling the aluminum liquid through the rotation of a screw; and adding the foaming agent through a first foaming agent feeding device, and continuously stirring through a screw, wherein the foaming stirring time is 1-2 min. The temperature is controlled by a heating device, three sections of control are adopted, the temperature of a stirring area is 670-690 ℃, the adding temperature of a foaming agent is 670-690 ℃, the temperatures of a foaming section and a foaming bin are 600-660 ℃, and the temperature of a mold outlet is 490-510 ℃; the tackifier can be any one of MnO2, SiC and Al2O3, and the addition content is 2%. The foaming agent can be any one of TiH2, CaH2 or Ni/TiH2 composite powder, and the content is 1.5%

(4) And the aluminum liquid added with the foaming agent is foamed and expanded in a foaming section, is gradually cooled to be in a semi-solid state, then enters a foaming bin for heat preservation, is extruded out, and enters a die to form an aluminum plate, and the heat preservation time of the foaming bin is 2-4 min.

(5) The forming process of the three-layer density gradient foamed aluminum plate comprises the following steps:

three-layer grade gradient density foamed aluminum is produced on the basis of the second embodiment.

Firstly, a left forming groove of a forming die receives a low-density gradient foamed aluminum solution, the outlet temperature of the forming groove is 490-510 ℃, and then cooling and heat preservation treatment is carried out for 2-4 min to keep the forming groove in a semi-solid state; the middle forming groove receives the foamed aluminum solution with medium density gradient, the outlet temperature of the middle forming groove is 490-510 ℃, the ceramic fiber baffle 116 is opened in an electric control mode, then the safety baffle 117 is quickly and electrically controlled to be closed, and then cooling and heat preservation treatment are carried out for 2-4 min to keep the middle forming groove in a semi-solid state; the right forming groove receives the foamed aluminum solution with high density gradient, the ceramic fiber baffle 1161 is opened in an electric control mode, then the safety baffle 1171 is quickly closed in an electric control mode, and then the foamed aluminum solution with different densities in the forming groove is cooled and pressurized, wherein the temperature processing mode is cooling to the solidification temperature; the foamed aluminum solution with high, medium and low density gradients are connected together, namely a three-layer foamed aluminum plate with different density gradients is formed.

The foregoing shows and describes the fundamental principles and principal features of the invention, together with the advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.