CN115090850A - Full-automatic production line and production method for centrifugal casting of high-temperature alloy castings - Google Patents

Abstract

The invention belongs to the technical field of centrifugal casting, and particularly discloses a full-automatic centrifugal casting production line and a production method for a high-temperature alloy casting, wherein the full-automatic centrifugal casting production line comprises a preparation area, a vacuum working area, a centrifugal casting working area, a cooling table and a disassembly area; the mechanical clamping jaws complete the assembly of the centrifugal casting chamber in the preparation area, the assembled centrifugal casting chamber is automatically transported to a vacuum working area by a roller transportation rail for vacuumizing, and the centrifugal casting chamber is transported to the centrifugal casting working area for rapid vacuum induction melting and centrifugal casting after vacuumizing. And simultaneously assembling the next centrifugal casting chamber and vacuumizing, wherein after the previous group of castings are formed, the heating coil automatically rises, the vacuum chamber after centrifugal casting is automatically conveyed to the cooling table by the roller track, and the next group of vacuum centrifugal casting chambers are installed on the rotating shaft for induction melting.

Description

A kind of high-temperature alloy casting centrifugal casting automatic production line and production method

technical field

The invention belongs to the technical field of centrifugal casting equipment, and in particular relates to an automatic production line and a production method for high-temperature alloy castings.

Background technique

With the improvement of the overall life and performance requirements of the engine, it is particularly important to realize the microstructure control of the superalloy castings for engines, and to improve the fatigue properties and other mechanical properties. Studies have shown that for the turbocharger turbine of a vehicle engine, the main loads of the turbine blades at medium temperature are fatigue and instantaneous tension, which requires materials with high tensile strength and fatigue strength and good crack growth resistance. However, at present, the turbocharger turbine of a vehicle engine is produced by investment casting. For such castings with complex structures and large wall thickness differences, defects such as shrinkage, porosity, and segregation often occur during the casting process, which seriously affects the quality of the castings. quality and yield. Moreover, the structure of turbine castings prepared by investment casting is mostly coarse columnar crystals, and the average grain size is greater than 4 mm. Casting defects, coarse grains, and anisotropy in structure and performance lead to the generation and development of fatigue cracks during use of castings, which seriously deteriorates the fatigue performance of turbines and shortens the service life of turbines.

In addition, in order to improve the performance and service life of the turbine, hot isostatic pressing is performed after investment casting, and the addition of this process greatly increases the manufacturing cost of castings. In addition, the investment casting process has low utilization rate of casting materials, complex process and long cycle, high demand for chemical auxiliary materials, high energy consumption, and harsh production environment. Therefore, it is urgent to develop a high-performance and long-life turbocharger turbine that can realize the fine-grained and dense structure of the body.

Centrifugal casting can use the high-speed rotation of the mold to make the molten metal in the mold fill the mold through centrifugal motion and form a casting, which is expected to form fine-grained and dense castings. However, the existing centrifugal casting machines mostly use the pouring type or swing arm type casting method, the vacuum cavity is large, and the vacuuming time is long, resulting in low production efficiency of a single piece. At the same time, the degree of automation of production is low, and a considerable proportion of the work still requires manual operation. The workers work in a high temperature environment, which is labor-intensive and safety is difficult to guarantee, which is not suitable for the production needs of high-temperature alloy castings.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the present invention provides a centrifugal casting automatic production line and production method for superalloy castings.

To achieve the above purpose, the complete technical scheme of the present invention includes:

An automatic production line for centrifugal casting of superalloy castings, comprising automatic production signal boxes, mechanical grippers, roller transport tracks, and sequentially connected preparation areas, vacuum work areas, centrifugal casting work areas, cooling tables, and disassembly areas;

The automatic production signal box sends out various instructions for the entire process, and the mechanical gripper and the roller transport track execute the instructions issued by the automatic production signal box; wherein the roller transport track is used to place the centrifugal casting chamber in the preparation area and the vacuum work area. , Conveying between the centrifugal casting work area, cooling table and dismantling area;

The preparation area includes a preheating furnace. The casting shells, crucibles, and bars are preheated in the preheating furnace. The mechanical gripper takes out the preheated shells, crucibles, and bars according to instructions, and assembles them. Centrifugal casting chamber, the centrifugal casting chamber includes a shell with a turntable inside, the mold shell is fixed on the turntable by a fixed seat and a mold shell pressure plate, the turntable and the casting chamber shell are sealed with magnetic fluid, and electromagnetic fluids are installed on both sides of the shell. valve;

The vacuum working area includes a vacuum pump, and the vacuum pump is connected to a solenoid valve on the casing to evacuate;

The centrifugal casting working area includes a heating coil, a tooling plate, and an electric rotating shaft. The heating coil is lifted and lowered by the driving mechanism, and the bar in the crucible is smelted; the tooling plate is used to fix the centrifugal casting after vacuuming. The electric rotating shaft is connected with the turntable shaft through the coupling and drives the turntable and the mold shell in the centrifugal casting chamber to rotate;

The cooling table is used for vacuum-breaking cooling of centrifugal casting after casting;

The dismantling area is used for dismantling the cooled centrifugal casting chamber and taking out the castings.

The crucible is a disposable aluminosilicate ceramic fiber crucible.

The crucible has a pre-opened bottom.

The fully automatic production line is an assembly line operation, including multiple sets of centrifugal casting chambers that operate in sequence.

The method for fully automatic production of superalloy castings using the production line includes the following steps:

(1) Assembly of centrifugal casting chamber: The automatic production signal box sends out instructions, and the mechanical gripper assembles the disposable crucible, bar and transparent quartz cover with pre-opened bottom to form the upper cover of the casting chamber. Placed on the mounting plate in the preparation area, the mechanical gripper assembles the preheated shell to the adjustable fixing seat of the turntable. The shell is fixed on the turntable by the adjustable fixing seat and the shell pressing plate. The pin is fixed on the turntable, the turntable and the casting chamber shell are sealed with magnetic fluid, and the two sides of the shell are provided with solenoid valves that can be connected to a vacuum pump; the mechanical gripper then covers the upper cover of the casting chamber to form an assembled centrifugal casting room;

(2) Vacuuming: The assembled centrifugal casting chamber is automatically transported to the vacuum working area by the roller transport track. The vacuum pump is connected to the solenoid valve on the shell of the centrifugal casting chamber for vacuuming. When the vacuum indication number reaches the set value, the solenoid valve automatic shutdown;

(3) Centrifugal casting: the centrifugal casting chamber after vacuuming is then automatically transported to the centrifugal casting work area by the roller transport track; in the centrifugal casting work area, the mechanical gripper fixes the centrifugal casting chamber on the tooling plate, and the turntable shaft passes through The coupling is connected with the electric rotating shaft; the automatic production signal box sends out instructions, the heating coil above the frame is automatically lowered under the drive of the driving mechanism, and the rapid vacuum induction melting and centrifugal casting process are carried out. During the centrifugal casting process, the molten metal heats up to When the liquidus is in, the electric rotating shaft is automatically opened to make the turntable and the shell reach the limited speed. After the melt is heated to the pouring temperature, it automatically flows into the runner from the pre-opening of the crucible. During the pouring and forming process, only the turntable inside the casting chamber drives the type The shell rotates, and the crucible is in a static state;

(4) Cooling: After the casting is formed, the heating coil automatically rises, the entire vacuum centrifugal casting chamber is transported to the cooling table by the roller transport track, and the solenoid valve is opened for vacuum breaking cooling;

(5) The cooled centrifugal casting chamber is automatically transported to the disassembly area, and the castings are taken out by mechanical grippers.

In step (2), after the centrifugal casting chamber is sent to the vacuum working area, the assembly work of the next group of centrifugal casting chambers is started in the preparation area.

In step (3), in the process of induction melting and centrifugal casting in the centrifugal casting chamber, the assembled next group of centrifugal casting chambers are vacuumed in the vacuum working area.

In step (3), the melting rate of the bar in the induction melting process is 2kg/min.

The superalloy casting obtained by the method is composed of fine equiaxed crystals, and the average grain size is between 0.5 and 1 mm.

The present invention adopts a fully automated method, and the vacuum centrifugal casting chamber adopts an encapsulation method, which can realize rapid automatic encapsulation and improve work efficiency. The vacuum process and the induction melting process are separated, and the vacuum pumping process and the induction melting process can be carried out synchronously instead of having to be executed sequentially like the traditional centrifugal casting process, which greatly improves the production efficiency. The whole process is controlled by the instructions issued by the automatic production signal box. The mechanical gripper and roller transport track are completed, which not only reduces the operation difficulty of the workers, improves the working environment, but also ensures the product quality and improves the product qualification rate. It can be used for the preparation of various superalloy fine-grained castings by changing the shells of different shapes and adjusting the smelting parameters.

Description of drawings

Figure 1 is a schematic top view of a fully automatic production process equipment for superalloy fine-grained castings.

Figure 2 is a three-dimensional schematic diagram of a fully automatic production process equipment for superalloy fine-grained castings.

Fig. 3 is the internal structure diagram of the vacuum centrifugal casting chamber.

In the picture: 1-material platform, 2-automatic production signal box, 3-preheating furnace, 4-mechanical gripper, 5- gripper guide rail, 6-quartz cover, 7-casting chamber upper cover, 8-upper cover Bracket, 9-solenoid valve, 10-vacuum gauge, 11-vacuum pump, 12-roller transport track, 13-liftable heating coil, 14-centrifugal casting chamber, 15-tooling plate, 16-positioning bracket, 17-cooling table, 18- Crucible, 19- Crucible holder, 20- Shell pressing plate, 21- Elastic pin, 22- Turntable, 23- Adjustable fixing seat, 24- Positioning pin, 25- Shell, 26- Centrifugal casting chamber shell, 27 -Magnetic fluid seal, 28-turntable shaft, 29-coupling, 30-electric shaft.

Detailed ways

The technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are only used as examples and are not used to limit the present application.

As shown in Figures 1-3, the fully automatic production line for superalloy fine-grain castings of the present invention includes a preparation area, a vacuum work area 11, a centrifugal casting work area, a cooling table and a disassembly area.

The main equipment involved includes a material platform 1, an automatic production signal box 2, a preheating furnace 3, multiple centrifugal casting chambers 14, a roller transport track 12 and a mechanical gripper 4, where the material platform 1 and the automatic production signal box 2 are located. On the front side of the preparation area, the material platform 1 is used to place all kinds of accessories required for production, and the preheating furnace 3 is located next to the frame of the entire equipment, which is used to preheat materials such as shells, crucibles, bars, and quartz covers.

A gripper guide 5 is provided above the mechanical gripper 4 for the mechanical gripper 4 to move back and forth; the entire process is performed by the mechanical gripper 4 and the roller transport track 12 according to the instructions issued by the automatic production signal box 2 .

The shell 25, the crucible 18, the bar material, the quartz cover 6, etc. are pre-heated in the preheating furnace to prevent the crucible 18 and the transparent quartz cover 6 from breaking due to sudden heat in the subsequent smelting process. The crucible 18 is a disposable silicon A zirconium acid ceramic fiber crucible, a transparent quartz cover 6 is provided outside the crucible 18, and the state of the alloy liquid can be observed. After the shell 25 is preheated to the specified temperature (900-1300°C), casting production begins.

In the preparation area, the automatic production signal box 2 issues an instruction, and the mechanical gripper 4 sequentially places the pre-opened bottom of the disposable crucible, the bar and the transparent quartz cover 6 on the crucible support 19, assembles the casting chamber upper cover 7 and places it on the crucible support 19. on the upper cover bracket 8 on the left. The centrifugal casting chamber shell 26 with the turntable 22 is placed on the mounting plate in the preparation area in advance, and the mechanical gripper 4 assembles the preheated mold shell 25 on the adjustable fixing seat 23 of the turntable 22 and fills with heat insulating sand.

The mold shell 25 is fixed on the turntable 22 by the adjustable fixing base 23 and the mold case pressing plate 20 . A magnetic fluid seal 27 is used between the turntable 22 and the casing 26 of the centrifugal casting chamber, so that the turntable 22 drives the mold shell 25 to rotate independently. Solenoid valves 9 are provided on both sides of the centrifugal casting chamber shell 26 , which can be connected to a vacuum pump 11 . The mechanical jaws 4 then cover the casting chamber cover 7 to form a centrifugal casting chamber 14 . The turntable shaft 28 of the turntable 22 in the centrifugal casting chamber 14 is connected to the electric shaft 30 in the work area through the coupling 29 in the subsequent process.

The assembled centrifugal casting chamber 14 is automatically transported to the vacuum working area by the roller transport track 12, and the vacuum pump 11 is connected to the solenoid valve 9 on the centrifugal casting chamber shell 26 for vacuuming. ~10Pa), solenoid valve 9 is automatically closed. The evacuated centrifugal casting chamber 14 is then automatically transported to the centrifugal casting work area by the roller transport track 12 .

The assembly work in the preparation area and the vacuuming work in the vacuum work area are both streamlined work. After the previous group of centrifugal casting chambers is sent to the vacuum work area, the next group of centrifugal casting chambers starts to assemble in the preparation area.

In the centrifugal casting working area, the mechanical clamping jaw 4 fixes the centrifugal casting chamber on the tooling plate 15 , and the rotary shaft 28 is connected with the electric rotary shaft 30 through the coupling 29 . The automatic production signal box sends out instructions, and the liftable heating coil 13 above the frame is automatically lowered under the drive of the drive mechanism, and the rapid vacuum induction melting and centrifugal casting process are carried out. The rapid induction melting adopts high-power power supply, and the melting rate can reach 2kg/min , the lifting and lowering heating coil 13 moves from top to bottom to ensure that the bar material is completely melted and the flow will not be interrupted during pouring. During the centrifugal casting process, when the molten metal heats up to the liquidus line, the electric rotating shaft 30 is automatically turned on, so that the turntable 22 and the mold shell 25 reach the limited rotational speed. . The pouring temperature is 50-200°C higher than the liquidus temperature of the alloy, especially selected between 70-150°C; the limited rotational speed is 300-600 r/min, preferably 400-500 r/min. During the pouring and molding process, only the turntable 22 inside the casting chamber drives the mold shell 25 to rotate, and the crucible 18 is in a static state to ensure the stability of the pouring process. In the process of induction melting and centrifugal casting, the next set of centrifugal casting chambers installed are vacuumed.

In this process, the moving speed of the induction melting coil plays a very critical role in the whole casting process. If the moving speed is too fast, the ingot cannot be fully melted, the degree of superheat is low, the viscosity of the alloy liquid is large, and the purity of the alloy liquid decreases, which is easy to Causes under-casting of thin-walled parts, and poor feeding in the final solidified part, which is prone to shrinkage porosity defects; if the moving speed is too slow, the pouring temperature will be too high, the heating power and time will be increased, and the temperature gradient is too large. Grain coarsening.

Therefore, the present invention adopts the following method to control the moving speed of the coil:

为线圈向下移动速度，单位为m/s；

为线圈加热功率，单位为W；

为线圈的移动行程，单位为m；

为铸造所用合金换算后的相变潜热，单位为J/Kg；

为铸造所用合金的浇注过热度，单位为℃；

为铸造所用合金的液态比热容，单位为J/(Kg·℃)；

为铸锭质量，单位为Kg；

为加热损耗系数，取值范围为0.3~0.9。In the formula,

is the downward moving speed of the coil, in m/s;

is the heating power of the coil, the unit is W;

is the moving stroke of the coil, the unit is m;

It is the latent heat of phase transformation after conversion of the alloy used for casting, the unit is J/Kg;

is the pouring superheat of the alloy used for casting, in °C;

is the liquid specific heat capacity of the alloy used for casting, in J/(Kg ℃);

is the mass of the ingot, the unit is Kg;

is the heating loss coefficient, the value range is 0.3~0.9.

After the casting is formed, the liftable heating coil 13 automatically rises, and the entire vacuum centrifugal casting chamber is transported to the cooling table 17 by the roller transport track 12, positioned by the positioning bracket 16, and the solenoid valve 9 is opened for vacuum breaking cooling. At the same time, the next set of centrifugal casting chambers assembled and evacuated can be immediately transported to the centrifugal casting work area for automatic induction melting.

The cooled centrifugal casting chamber is automatically transported to the dismantling area, and the castings are taken out by the mechanical gripper 4 .

This method realizes the simultaneous execution of the vacuuming process and the induction melting process, which greatly improves the production efficiency. The whole process is completed by the instructions issued by the automatic production signal box to control the mechanical gripper and the roller transport track, which not only reduces the difficulty of the workers' operation, improves the labor environment, but also ensures the product quality and improves the product qualification rate. The invention is suitable for the preparation of various high-temperature alloy fine-grained castings by changing the shells of different shapes and adjusting the smelting parameters.

The above-mentioned production line and process method can prepare various superalloy fine-grained castings by customizing different shapes of shells and adjusting smelting parameters. The overall structure of the superalloy turbine casting obtained by this automated production process is composed of fine equiaxed crystals, and the grain size is between 0.1 and 1 mm, which significantly improves the fatigue performance of the product. In addition, the centrifugal action improves the shrinkage and filling ability of the molten metal, which not only ensures the dimensional accuracy of complex precision castings, but also improves the density of the castings, and reduces defects such as shrinkage porosity and inclusions, thereby improving the use of the product. life.

The above applications are only some embodiments of the present application. For those of ordinary skill in the art, without departing from the inventive concept of the present application, several modifications and improvements can also be made, which all belong to the protection scope of the present application.

Claims (9)

1. A centrifugal casting full-automatic production line for high-temperature alloy castings is characterized by comprising an automatic production signal box, a mechanical clamping jaw, a roller conveying track, a preparation area, a vacuum working area, a centrifugal casting working area, a cooling table and a disassembly area which are sequentially connected;

the automatic production signal box sends various instructions of the whole process flow, and the mechanical clamping jaw and the roller conveying track execute the instructions sent by the automatic production signal box; wherein the drum transport track is used for transporting the centrifugal casting chamber among the preparation area, the vacuum working area, the centrifugal casting working area, the cooling table and the disassembly area;

the preparation area comprises a preheating treatment furnace, a shell for casting, a crucible and a bar are preheated in the preheating treatment furnace in advance, a mechanical clamping jaw takes out the preheated shell, crucible and bar according to an instruction, and a centrifugal casting chamber is assembled, the centrifugal casting chamber comprises a shell, a rotary disc is arranged in the shell, the shell is fixed on the rotary disc through a fixed seat and a shell pressing plate, the rotary disc and the shell of the casting chamber are sealed through magnetic fluid, and electromagnetic valves are arranged on two sides of the shell;

the vacuum working area comprises a vacuum pump, and the vacuum pump is connected with an electromagnetic valve on the shell for vacuumizing;

the centrifugal casting working area comprises a heating coil, a tooling plate and an electric rotating shaft, the heating coil is driven by a driving mechanism to lift and smelt the bar stock in the crucible; the tool plate is used for fixing the vacuumized centrifugal casting chamber, and the electric rotating shaft is connected with the rotating disc shaft through the coupler and drives the rotating disc and the shell in the centrifugal casting chamber to rotate;

the cooling table is used for vacuum breaking cooling of the centrifugal casting after casting;

the disassembly area is used for disassembling the cooled centrifugal casting chamber and taking out the casting.

2. A full automatic production line for centrifugal casting of superalloy castings according to claim 1, wherein the crucible is a disposable alumina silicate ceramic fiber crucible.

3. A fully automated production line for centrifugal casting of superalloy castings according to claim 2, wherein the crucible has a pre-opened bottom.

4. A centrifugal casting full-automatic production line for high-temperature alloy castings according to claim 3, characterized in that the full-automatic production line is a production line and comprises a plurality of groups of centrifugal casting chambers which are operated in sequence.

5. The method for full-automatic centrifugal casting production of high-temperature alloy castings by adopting the production line of claim 4 is characterized by comprising the following steps of:

(1) assembling a centrifugal casting chamber: the automatic production signal box sends an instruction, the mechanical clamping jaw assembles a disposable crucible with a pre-opened bottom, a bar stock and a transparent quartz cover into an upper cover of a casting chamber, a centrifugal casting chamber shell with a rotary disc arranged inside is arranged on a mounting plate of a preparation area in advance, the mechanical clamping jaw assembles a preheated shell onto an adjustable fixing seat of the rotary disc, the shell is fixed on the rotary disc through the adjustable fixing seat and a shell pressing plate, the shell pressing plate is fixed on the rotary disc through a positioning pin, the rotary disc and the casting chamber shell are sealed by magnetic fluid, and electromagnetic valves capable of being externally connected with a vacuum pump are arranged on two sides of the shell; the mechanical clamping jaw covers the upper cover of the casting chamber to form an assembled centrifugal casting chamber;

(2) vacuumizing: the assembled centrifugal casting chamber is automatically transported to a vacuum working area by a roller transportation track, a vacuum pump is connected with an electromagnetic valve on a shell of the centrifugal casting chamber for vacuumizing, and the electromagnetic valve is automatically closed when the vacuum representation number reaches a set value;

(3) centrifugal casting: the centrifugal casting chamber after the vacuum pumping is automatically transported to a centrifugal casting working area by a roller transportation rail; in a centrifugal casting working area, a mechanical clamping jaw fixes the centrifugal casting chamber on a tooling plate, and a turntable shaft is connected with an electric rotating shaft through a coupling; the automatic production signal box sends out an instruction, a heating coil above the rack automatically descends under the driving of the driving mechanism, and fast vacuum induction melting and centrifugal casting processes are carried out, during the centrifugal casting process, when molten metal is heated to a liquidus line, the electric rotating shaft is automatically opened, so that the rotating disc and the shell reach a limited rotating speed, after the temperature of a melt is raised to a pouring temperature, the melt automatically flows into a pouring gate from a pre-opening of the crucible, only the rotating disc in the casting chamber drives the shell to rotate during the pouring and forming processes, and the crucible is in a static state;

(4) and (3) cooling: after the casting is formed, the heating coil automatically rises, the whole vacuum centrifugal casting chamber is transported to a cooling table by a roller transportation rail, and an electromagnetic valve is opened for vacuum breaking and cooling;

(5) the cooled centrifugal casting chamber is automatically transported to a disassembly area and the casting is removed by the mechanical jaws.

6. A method for carrying out the full automatic production of the centrifugal casting of the high-temperature alloy castings according to the claim 5, characterized in that in the step (2), after the centrifugal casting chambers are sent to the vacuum working area, the assembling work of the next group of centrifugal casting chambers is started in the preparation area.

7. The method for fully automatically producing the high-temperature alloy castings through centrifugal casting according to claim 6, wherein in the step (3), the centrifugal casting chambers are in the induction melting and centrifugal casting processes, and the next assembled centrifugal casting chamber group is vacuumized in a vacuum working area.

8. The method for fully automatically producing the centrifugal casting of the high-temperature alloy castings according to claim 7, wherein in the step (3), the bar stock has a melting rate of 2kg/min in the induction melting process.

9. Superalloy castings obtained by the method of any of claims 5 to 8, wherein the superalloy castings are composed of fine equiaxed grains with an average grain size between 0.5 and 1 mm.

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