Device and method for preparing aluminum alloy sample with two ends cooled

Abstract

The invention belongs to the technical field of aluminum alloy casting, and particularly relates to a preparation device and method for an aluminum alloy sample with two ends cooled. According to the technical scheme, the preparation device of the aluminum alloy sample with the two ends cooled comprises a cavity, a cavity cover, a sprue plug, a shrinkage compensation plate, a cooling plate and a spraying system, a cavity is formed in the cavity, and the two ends of the cavity are open; the cavity cover is placed on the cavity body and used for covering the mold cavity, the cavity cover is provided with a pouring hole, and the pouring plug is used for blocking the pouring hole; the two shrinkage compensation plates are arranged at the two ends of the cavity respectively, a cooling plate is arranged on the outer side of each shrinkage compensation plate, and two nozzles of the spraying system face the two cooling plates respectively. According to the preparation device and method for the aluminum alloy sample with the two ends cooled, the small-size aluminum alloy solidification structure sample can be prepared, and the structure and segregation characteristics of a large aluminum alloy ingot with the approximate cooling direction from outside to inside are obtained.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy casting technology, and specifically relates to an apparatus and method for preparing aluminum alloy samples cooled at both ends. Background Technology

[0002] Aluminum alloys, as a low-density, high-strength metallic material, are widely used in transportation, aerospace, and information communication fields. Common aluminum alloys are divided into cast aluminum alloys and wrought aluminum alloys. Cast aluminum alloys can be used directly after casting and simple grinding and cutting processes, without involving deformation. Wrought aluminum alloys, on the other hand, are cast into ingots and then processed through extrusion, rolling, and stamping before they can be used.

[0003] The production of wrought aluminum alloy ingots typically employs a semi-continuous casting method. The process usually involves molten aluminum alloy first solidifying in a crystallizer to form a shell, then the solidified portion gradually moving downwards under the traction of an ingot auger, ultimately forming a metal ingot several meters high. During this process, the solidification direction of the ingot is from the outside in. After detaching from the crystallizer, a sprayer sprays cooling water onto the ingot surface to allow the unsolidified portion inside to continue solidifying. Different aluminum alloy compositions exhibit different microstructures, segregation behaviors, and heat transfer tendencies during the semi-continuous casting process. These microstructures and elemental distributions directly affect the final quality of the ingot. Before the industrial production of new alloys, it is necessary to evaluate the potential microstructure and properties of the final ingot. Current technologies use industrial equipment to produce large-sized test samples of new alloy compositions, resulting in a waste of funds and energy. Summary of the Invention

[0004] This invention provides an apparatus and method for preparing aluminum alloy samples cooled at both ends, which can prepare solidification microstructure samples of small-sized aluminum alloys and obtain microstructure and segregation characteristics of large aluminum alloy ingots with a cooling direction approximately from the outside to the inside.

[0005] The technical solution of the present invention is as follows: An apparatus for preparing an aluminum alloy sample cooled at both ends includes a cavity, a cavity cover, a sprue plug, a shrinkage compensation plate, a cooling plate, and a spraying system. The cavity has a mold cavity at its upper part, and the two ends of the mold cavity are open. The cavity cover is placed on the cavity to cover the mold cavity. The cavity cover has a sprue hole, and the sprue plug is used to block the sprue hole. Two shrinkage compensation plates are respectively disposed at both ends of the cavity, and a cooling plate is disposed on the outer side of each shrinkage compensation plate. Two nozzles of the spraying system are respectively directed towards the two cooling plates.

[0006] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the cross-section of the cavity is a trapezoid with a smaller bottom and a larger top to form a draft angle, and the angle between the inner side surface and the bottom surface of the cavity is an obtuse angle.

[0007] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the cavity cover is divided into two symmetrical parts, each part having a notch on its side. After the two parts are combined, the two notches are joined together to form the gating hole; the length of the cavity cover is the same as that of the cavity body.

[0008] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the lower cross-section of the gate plug is the same size as the gating hole, and the upper cross-section of the gate plug is larger than the gating hole.

[0009] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the shrinkage compensation plate has a hole in the middle, and the shape of the hole is the same as the cross-section of the cavity.

[0010] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the cooling plate includes a bottom plate and a vertical plate connected at right angles, the bottom plate being placed below the cavity, and the vertical plate being attached to the outside of the shrinkage compensation plate.

[0011] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the cavity and cavity cover are equipped with accessories of different lengths, and the shrinkage compensation plate is equipped with accessories of different thicknesses.

[0012] Furthermore, in the apparatus for preparing aluminum alloy samples cooled at both ends, the cavity, cavity cover, sprue plug, and shrinkage compensation plate are made of aluminum silicate heat-resistant material; the cooling plate is made of graphite, copper alloy, or iron alloy.

[0013] A method for preparing an aluminum alloy sample cooled at both ends, utilizing the aforementioned apparatus for preparing an aluminum alloy sample cooled at both ends, includes the following steps: 1) Place the cavity, cavity cover, gate plug, and shrinkage compensation plate in a drying oven and preheat to a certain temperature; 2) Melt the aluminum alloy raw material, refine it, remove slag to form a melt, and then control it at the target temperature for later use; 3) Remove the cavity, cavity cover, and shrinkage compensation plate from the drying oven, assemble them with the spray system and cooling plate, place them on the work platform, and turn on the spray nozzles of the spray system; 4) Pour the melt into the mold cavity through the gating hole, and place the gating plug at the gating hole after casting is completed; 5) After the target time, remove the cooling plate and shrinkage compensation plate so that the coolant sprayed from the nozzle can be directly sprayed onto the solidified parts at both ends of the ingot; 6) After the melt has completely cooled, the ingot is removed from the cavity to obtain a solidification structure sample of the aluminum alloy.

[0014] The beneficial effects of this invention are as follows: 1. This invention uses only a few hundred grams of aluminum alloy material to prepare solidification samples, which can obtain the microstructure and segregation characteristics of large aluminum alloy ingots with cooling direction from the outside to the inside. Compared with the scale of ordinary pilot-scale tests of large semi-continuous ingots, the scale is greatly reduced, which greatly reduces the time and money costs required for the experiment.

[0015] 2. The cavity, cavity cover, shrinkage compensation plate and cooling plate of the present invention are all modularly designed. Different lengths, different gating hole positions and different material cooling plates can be selected according to the needs. Variable parameters such as ingot length, casting temperature, casting position, initial cooling rate and alloy composition can be arbitrarily combined to obtain alloy ingots that solidify under specific conditions. Attached Figure Description

[0016] Figure 1 A schematic diagram of the apparatus for preparing an aluminum alloy sample cooled at both ends; Figure 2 An exploded view of the apparatus for preparing an aluminum alloy sample cooled at both ends. Figure 3 Macroscopic microstructure diagram of the solidified microstructure sample prepared in Example 1; Figure 4 This is a macroscopic microstructure diagram of the solidified tissue sample prepared in Example 2. Detailed Implementation

[0017] like Figure 1 , 2 As shown, an apparatus for preparing an aluminum alloy sample cooled at both ends includes a cavity 1, a cavity cover 2, a sprue plug 3, a shrinkage compensation plate 4, a cooling plate 5, and a spray system. The cavity 1 has a cavity 7 at its upper part, with openings at both ends. The cross-section of the cavity 7 is trapezoidal, smaller at the bottom and larger at the top, to form a draft angle. The angle between the inner side surface and the bottom surface of the cavity 7 is obtuse. The cavity cover 2 is placed on the cavity 1 to cover the cavity 7. The cavity cover 2 has a sprue and is divided into two symmetrical parts, each with a notch 8 on its side. The two parts are combined, and the two notches 8 form the sprue. The length of the cavity cover 2 is the same as that of the cavity 1. The lower cross-section of the gate 3 is the same size as the gating hole, and the upper cross-section of the gate plug 3 is larger than the gating hole. The gate plug 3 is used to block the gating hole. Two shrinkage compensation plates 4 are respectively disposed at both ends of the cavity 1. The shrinkage compensation plate 4 has a hole 9 in the middle, and the shape of the hole 9 is the same as the cross-section of the cavity 7. A cooling plate 5 is disposed on the outside of each shrinkage compensation plate 4. The cooling plate 5 includes a bottom plate 10 and a vertical plate 11 connected at right angles. The bottom plate 10 is placed below the cavity 1, and the vertical plate 11 is attached to the outside of the shrinkage compensation plate 4. The two nozzles 6 of the spray system are respectively directed towards the vertical plates 11 of the two cooling plates 5.

[0018] The cavity 1 and cavity cover 2 are equipped with accessories of different lengths, and the shrinkage compensation plate 4 is equipped with accessories of different thicknesses.

[0019] The cavity 1, cavity cover 2, sprue plug 3, and shrinkage compensation plate 4 are made of aluminum silicate heat-resistant material; the cooling plate 5 is made of copper alloy.

[0020] Cavity 1 is used to hold molten metal and provide insulation. It is made of heat-resistant aluminum silicate material. Its cavity 7 has a draft angle to facilitate the demolding process after the alloy melt solidifies. Cavity cover 2 is used to prevent molten metal from overflowing from the top of cavity 7 and provides a certain degree of insulation. It has a gating hole, through which the molten metal flows into cavity 7. Cavity cover 2 is also made of heat-resistant aluminum silicate material and is divided into left and right parts. The modular design is to prevent the molten metal from overflowing from the gating hole and solidifying, which would cause demolding difficulties. Cooling plate 5 consists of a bottom plate 10 and a vertical plate 11 that are perpendicular to each other. The vertical plate 11 forms the end wall of the cavity 7, preventing molten metal from flowing out of the openings at both ends of the cavity 7 and providing cooling during the initial solidification stage. The bottom plate 10 is a fixed part, located below the cavity 1 during casting, relying on the gravity of the cavity 1 itself to keep the vertical plate 11 in contact with the end face of the cavity 1. The spray system is located outside the cooling plate 5, used to spray coolant onto the cooling plate 5 and both ends of the ingot during solidification. The gate plug 3 is placed at the gating hole after casting to slow down the rate of heat loss from the gating hole, and its material is the same as the upper cavity cover 2 of the cavity 1. The shrinkage compensation plate 4 is used to remove the gap between the molten metal and the cooling plate 5 caused by shrinkage after solidification, allowing the spray system to directly spray coolant onto both ends of the ingot, preventing water accumulation at both ends of the cavity 1 from wetting the entire lower surface of the cavity 1 and changing the cooling conditions, and also facilitating the reuse of the cavity 1. Example 1

[0021] A method for preparing an aluminum alloy sample cooled at both ends, utilizing the aforementioned apparatus for preparing an aluminum alloy sample cooled at both ends, includes the following steps: 1) An alloy with the target composition was prepared using intermediate alloys and pure metals, with the following composition (mass fraction): Cu: 4.5%; Zr: 0.5%; Cr: 0.8%, with the remainder being Al and unavoidable impurity elements; 2) Place cavity 1, cavity cover 2, shrinkage compensation plate 4 and gate plug 3 in a drying oven and heat to 300℃ and keep warm; cavity 1 is 20cm long and shrinkage compensation plate 4 is 3mm thick; 3) Place the alloy raw material in a crucible, melt it in a resistance furnace, and refine it with C2Cl6 after the temperature reaches 750℃; 4) After removing the slag, evenly spread the covering agent on the surface of the melt and stabilize the melt temperature at 700℃; 5) Remove the chamber 1, chamber cover 2 and shrinkage compensation plate 4 from the drying oven after they have reached the predetermined temperature, and assemble them with the cooling plate 5 and the spray system, and turn on the spray system; 6) Cast the prepared alloy melt into the cavity 7 through the gating hole located in the middle of the length direction. After casting, place the gating plug 3 at the gating hole.

[0022] 7) After casting is completed for 20 seconds, remove the cooling plate 5 and the shrinkage compensation plate 4 so that the coolant can be sprayed directly onto the surfaces of both ends of the ingot. After spraying for 1 minute, turn off the spraying system. Finally, after casting is completed for 5 minutes, take out the completely solidified ingot to obtain a solidification structure sample of aluminum alloy.

[0023] Before casting, the preheated cavity 1, cavity cover 2, gate plug 3, and shrinkage compensation plate 4 are assembled with the remaining parts. Preheating the mold ensures that the solidification direction of the molten metal is from both horizontal sides inward, preventing excessive heat loss due to contact with the aluminum silicate mold cavity wall and premature solidification. When the alloy melt reaches the required temperature, the spray system is turned on, and the alloy melt is poured into the cavity 7 through the gate of cavity cover 2. After a certain period of time, some of the melt has solidified. At this point, the cooling plate 5 and shrinkage compensation plate 4 are removed, allowing the coolant to be sprayed directly onto the solidified surfaces at both ends of the ingot.

[0024] The macrostructure of the solidified sample obtained is as follows: Figure 3 As shown, since the device is completely symmetrical and the casting position is at the center, the microstructure of half the length of the ingot is already representative. It can be seen that the microstructure of the ingot near the cooling plate 5 exhibits a distinct columnar crystal morphology. At a position about 3.5 cm away from the cooling plate 5, the grains in the ingot change from columnar crystals to equiaxed crystals, all the way to the center of the ingot. Example 2

[0025] The difference from Example 1 is that the alloy has the following composition (mass fraction): Cu: 4.5%; Zr: 0.5%; Cr: 0.8%; Ti: 0.2%; B: 0.04%, with the remainder being Al and unavoidable impurity elements.

[0026] The macrostructure of the solidified sample obtained is as follows: Figure 4 As shown, compared to Example 1, the addition of Ti and B elements significantly reduced the grain size of the alloy, and the columnar crystal structure completely disappeared.

[0027] The above descriptions are merely examples of embodiments of the present invention, and do not elaborate on commonly known characteristics and structures of the methods. It is obvious to those skilled in the art that the present invention is not limited to the processes of the foregoing exemplary embodiments. Elements of the invention can be implemented in other specific forms without departing from the basic nature and spirit of the invention. Therefore, the embodiments provided above should be considered exemplary and non-limiting. The scope of the technical claims of the invention should be defined by the appended claims, not by the foregoing embodiments and descriptions. Therefore, the present invention is intended to cover all variations falling within the meaning and scope of equivalents of the claims. Reference numerals in the claims should not be construed as limiting the claims.

Claims

1. An apparatus for preparing an aluminum alloy sample cooled at both ends, characterized in that, The device includes a cavity, a cavity cover, a sprue plug, shrinkage compensation plates, cooling plates, and a spray system. The cavity has a mold cavity at its upper part, with openings at both ends. The cavity cover is placed on the cavity to cover the mold cavity and has a sprue hole. The sprue plug is used to block the sprue hole. Two shrinkage compensation plates are respectively disposed at both ends of the cavity, and a cooling plate is disposed on the outer side of each shrinkage compensation plate. Two nozzles of the spray system are respectively directed towards the two cooling plates.

2. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The cross-section of the cavity is trapezoidal with a smaller bottom and a larger top to form a draft angle, and the angle between the inner side surface and the bottom surface of the cavity is an obtuse angle.

3. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The cavity cover is divided into two symmetrical parts, each part having a notch on its side. After the two parts are combined, the two notches are joined together to form the pouring hole. The length of the cavity cover is the same as that of the cavity.

4. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The lower cross-section of the gate plug is the same size as the gating hole, and the upper cross-section of the gate plug is larger than the gating hole.

5. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The shrinkage compensation plate has a hole in the middle, and the shape of the hole is the same as the cross-section of the cavity.

6. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The cooling plate includes a bottom plate and a vertical plate connected at right angles. The bottom plate is placed below the cavity, and the vertical plate is attached to the outside of the shrinkage compensation plate.

7. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The cavity and cavity cover are equipped with accessories of different lengths, and the shrinkage compensation plate is equipped with accessories of different thicknesses.

8. The apparatus for preparing an aluminum alloy sample cooled at both ends according to claim 1, characterized in that, The cavity, cavity cover, sprue plug, and shrinkage compensation plate are made of aluminum silicate heat-resistant material; the cooling plate is made of graphite, copper alloy, or iron alloy.

9. A method for preparing an aluminum alloy sample cooled at both ends, characterized in that, The apparatus for preparing an aluminum alloy sample cooled at both ends as described in any one of claims 1-8 includes the following steps: 1) Place the cavity, cavity cover, gate plug, and shrinkage compensation plate in a drying oven and preheat to a certain temperature; 2) Melt the aluminum alloy raw material, refine it, remove slag to form a melt, and then control it at the target temperature for later use; 3) Remove the cavity, cavity cover, and shrinkage compensation plate from the drying oven, assemble them with the spray system and cooling plate, place them on the work platform, and turn on the spray nozzles of the spray system; 4) Pour the melt into the mold cavity through the gating hole, and place the gating plug at the gating hole after casting is completed; 5) After the target time, remove the cooling plate and shrinkage compensation plate so that the coolant sprayed from the nozzle can be directly sprayed onto the solidified parts at both ends of the ingot; 6) After the melt has completely cooled, the ingot is removed from the cavity to obtain a solidification structure sample of the aluminum alloy.

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