CN112692234A - Combined casting process of large precision casting - Google Patents
Combined casting process of large precision casting Download PDFInfo
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- CN112692234A CN112692234A CN202011532293.XA CN202011532293A CN112692234A CN 112692234 A CN112692234 A CN 112692234A CN 202011532293 A CN202011532293 A CN 202011532293A CN 112692234 A CN112692234 A CN 112692234A
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- shell
- casting
- sprue
- riser
- casting body
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/22—Moulds for peculiarly-shaped castings
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
Abstract
The invention discloses a combinable large-piece precision casting runner process, which comprises the following steps: calculating the size design of a sprue in a casting body, calculating the size design of a sprue and calculating the size of a formed heat-insulating riser; manufacturing a casting body wax mould and a single sprue wax mould according to a process diagram; preparing a shell by adopting a composite process, dewaxing by adopting a water bath method, roasting the shell, completing the assembly of a casting body shell, a sprue shell and a heat-insulating riser after roasting, and placing the casting body shell, the sprue shell and the heat-insulating riser in a sand box for sand burying and pouring after completing the assembly; the invention has simple process and low casting cost, can greatly reduce the production intensity of workers, breaks through the limitation that the precision casting of a casting above 200kg cannot be produced, and brings the feasibility of operation for the producibility of the precision casting of large pieces.
Description
Technical Field
The invention relates to the technical field of investment precision casting, in particular to a combined casting process of a large precision casting.
Background
At present, with the continuous development of the industry in China, the demand of precision castings is gradually increased, especially the requirement of large precision castings is higher and higher, the maximum conventional precision casting can be 200kg, and the size is within 1m x 1 m.
Disclosure of Invention
The invention mainly aims to provide a combined casting process of a large precision casting, which can effectively solve the problems in the background technology.
In order to achieve the purpose, the invention adopts the technical scheme that: a combined casting process of a large precision casting comprises the following steps:
1) preparation of the process: and (4) placing machining allowance according to the drawing requirement, calculating the size of an inner pouring gate according to the thermal pitch circle and the modulus, calculating the sizes of a feeding head and a sprue, and calculating the size of a formed heat-insulating head.
2) Preparation of production: according to the requirements of a process diagram, a casting body auxiliary die, a sprue auxiliary die and an insulation riser adopt a forming riser, and the die is molded according to the process diagram;
3) molding: preparing a casting body wax mold by adopting a casting body mold, and preparing a sprue wax mold by adopting a sprue mold;
4) preparing a shell: preparing a shell by adopting a composite method, wherein the front three layers adopt silica sol slurry, the rear reinforcing layer adopts water glass slurry, and the casting body and the sprue are separately and independently coated to prepare the shell so as to prepare a casting body shell and a sprue shell;
5) dewaxing: before dewaxing, washing the surfaces to be bonded of the casting body shell and the sprue shell by hot water, washing away residual slurry and sand on the surfaces to expose wax, and then dewaxing by a water bath method;
6) roasting: roasting the casting body shell and the sprue shell at the high temperature of 950-1050 ℃ for 3 hours to form a casting body shell and a sprue shell;
7) assembling a shell: respectively bonding the casting body shell with the sprue shell and the heat-insulating riser by using refractory mortar to form a combined shell;
8) pouring: and (4) embedding the combined shell in the step (6) into a sand box, densely distributing the molding sand, sealing the periphery of the sand box at the bottom, connecting a vacuumizing device, and then pouring from the sprue shell.
Preferably, the casting body wax mold in the step 3 is provided with a riser wax mold at a hot node, a riser shell is formed through shell making in the step 4, and the heat-insulating riser is connected with the riser shell in an inserting mode.
Preferably, a step groove is formed in the riser shell, and the bottom and the side wall of the heat-insulating riser are bonded with the step groove.
Preferably, a socket wax mold is arranged on the side surface of the casting body wax mold in the step 3, a socket shell is formed through shell manufacturing in the step 4, a spigot wax mold is arranged on the side surface of the sprue wax mold in the step 3, a spigot shell is formed through shell manufacturing in the step 4, and the spigot shell is bonded on the outer side of the socket shell.
Preferably, in the step 7, after the casting body shell, the sprue shell and the heat-preservation riser are bonded, heavy pressing is carried out for 10-15 minutes along the bonding direction.
Preferably, in the step 7, the casting body shell, the sprue shell and the heat-insulating riser are bonded, then the casting body shell, the sprue shell and the heat-insulating riser are stressed and ventilated at the outer side, and the solidification and bonding of the refractory mortar are accelerated.
Preferably, the bottom of the sand box in the step 8 is communicated with a hot air pipe, the hot air pipe is connected with a ventilation device, hot air is introduced after the casting is finished, the temperature of the introduced hot air is 50-90 ℃, and the temperature of the introduced hot air is reduced by 5 ℃ every ten minutes.
Compared with the prior art, the invention has the following beneficial effects: the invention has simple process, low casting cost and convenient implementation, greatly reduces the production intensity of workers, breaks through the limitation that the precision casting of more than 200kg of castings cannot be produced, and brings feasibility of operation for the producibility of precision casting of large castings.
Drawings
FIG. 1 is a schematic view of a modular shell structure according to an embodiment of the present invention;
in the figure: 1. casting body shell molding; 2. a sprue shell; 3. insulating a riser; 4. a riser shell; 5. a step groove; 6. a socket shell; 7. a looping shell.
Detailed Description
In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.
Example 1
As shown in FIG. 1, the prior 16-300 gate valve element has a single weight of casting blank 275kg, the length, width and height of the outline dimension are 920 x 650 x 720 (unit mm), the process is designed to be horizontally assembled and welded, the weight of a casting head is 120kg, and the total weight of molten steel is about 395 kg. Coating is with rotation type stirring thick liquid jar working dimension 1100mm, the overhanging runner length of the two end flange runners of this 16-300 gate valve spare technical design is 45mm, the head office is 920+45+45 and 1010mm, satisfy current thick liquid jar 1100 equipment use, now make foundry goods body and runner split, the outline size with whole module that just so artificial reduces, can put into the thick liquid jar and be stained with the oar operation, the back end system shell finishes the back with runner position clean up, make up and can obtain the module of taking the gating system, concrete precision casting technology is as follows:
1) preparation of the process: and (4) placing machining allowance according to the drawing requirement, calculating the size of an inner pouring gate according to the thermal pitch circle and the modulus, calculating the sizes of a feeding head and a sprue, and calculating the size of a formed heat-insulating head.
2) Preparation of production: according to the requirements of a process diagram, a casting body auxiliary die, a sprue auxiliary die and an insulation riser adopt a forming riser, and the die is molded according to the process diagram;
3) molding: preparing a casting body wax mold by adopting a casting body mold, and preparing a sprue wax mold by adopting a sprue mold;
4) preparing a shell: preparing a shell by adopting a composite method, wherein the front three layers adopt silica sol slurry, the rear reinforcing layer adopts water glass slurry, and the casting body and the sprue are separately and independently coated to prepare the shell so as to prepare a casting body shell and a sprue shell;
5) dewaxing: before dewaxing, washing the surfaces to be bonded of the casting body shell and the sprue shell by hot water, washing away residual slurry and sand on the surfaces to expose wax, and then dewaxing by a water bath method;
6) roasting: roasting the casting body shell and the sprue shell at the high temperature of 950-1050 ℃ for 3 hours to form a casting body shell and a sprue shell;
7) assembling a shell: respectively bonding the casting body shell with the sprue shell and the heat-insulating riser by using refractory mortar to form a combined shell;
8) pouring: and (4) embedding the combined shell in the step (6) into a sand box, densely distributing the molding sand, sealing the periphery of the sand box at the bottom, connecting a vacuumizing device, and then pouring from the sprue shell.
In this embodiment, the casting body wax mold in the step 3 is provided with a riser wax mold at a hot node, a riser shell is formed through shell making in the step 4, and the heat-insulating riser is inserted into the riser shell.
In this embodiment, a step groove is formed inside the feeder shell, and the bottom and the side wall of the insulating feeder are bonded to the step groove.
In this embodiment, the socket wax pattern is formed on the side surface of the casting body wax pattern in step 3, the socket shell is formed through shell making in step 4, the sprue wax pattern is formed on the side surface of the sprue wax pattern in step 3, the sprue shell is formed through shell making in step 4, and the sprue shell is bonded to the outer side of the socket shell.
In this embodiment, in the step 7, after the casting body shell, the sprue shell and the insulating riser are bonded, heavy pressing is performed for 10 to 15 minutes along the bonding direction.
In this embodiment, in the step 7, the casting body shell, the sprue shell and the insulating riser are bonded, and then, ventilation is performed on the outer side while heavy pressing is performed, so that solidification and bonding of the refractory mortar are accelerated.
In this embodiment, the bottom of the sand box in step 8 is communicated with a hot air pipe, the hot air pipe is connected with a ventilation device, hot air is introduced after the casting is completed, the temperature of the introduced hot air is 50-90 ℃, and the temperature of the introduced hot air is reduced by 5 ℃ every ten minutes.
While certain exemplary embodiments of the present invention have been described above by way of illustration only, it will be apparent to those of ordinary skill in the art that the described embodiments may be modified in various different ways without departing from the spirit and scope of the invention. Accordingly, the drawings and description are illustrative in nature and should not be construed as limiting the scope of the invention.
Claims (7)
1. A combined casting process of a large precision casting is characterized in that: the method comprises the following steps:
1) preparation of the process: and (4) placing machining allowance according to the drawing requirement, calculating the size of an inner pouring gate according to the thermal pitch circle and the modulus, calculating the sizes of a feeding head and a sprue, and calculating the size of a formed heat-insulating head.
2) Preparation of production: according to the requirements of a process diagram, a casting body auxiliary die, a sprue auxiliary die and an insulation riser adopt a forming riser, and the die is molded according to the process diagram;
3) molding: preparing a casting body wax mold by adopting a casting body mold, and preparing a sprue wax mold by adopting a sprue mold;
4) preparing a shell: preparing a shell by adopting a composite method, wherein the front three layers adopt silica sol slurry, the rear reinforcing layer adopts water glass slurry, and the casting body and the sprue are separately and independently coated to prepare the shell so as to prepare a casting body shell and a sprue shell;
5) dewaxing: before dewaxing, washing the surfaces to be bonded of the casting body shell and the sprue shell by hot water, washing away residual slurry and sand on the surfaces to expose wax, and then dewaxing by a water bath method;
6) roasting: roasting the casting body shell and the sprue shell at the high temperature of 950-1050 ℃ for 3 hours to form a casting body shell and a sprue shell;
7) assembling a shell: respectively bonding the casting body shell with the sprue shell and the heat-insulating riser by using refractory mortar to form a combined shell;
8) pouring: and (4) embedding the combined shell in the step (6) into a sand box, densely distributing the molding sand, sealing the periphery of the sand box at the bottom, connecting a vacuumizing device, and then pouring from the sprue shell.
2. The combined casting process of the large-piece precision casting according to claim 1, characterized in that: and (4) forming a riser wax mold at a hot node of the casting body wax mold in the step (3), forming a riser shell through shell manufacturing in the step (4), and inserting the heat-insulating riser into the riser shell.
3. The combined casting process of the large-piece precision casting according to claim 2, characterized in that: and a step groove is formed in the riser shell, and the bottom and the side wall of the heat-insulating riser are bonded with the step groove.
4. The combined casting process of the large-piece precision casting according to claim 1, characterized in that: and (3) opening a socket wax mold on the side surface of the casting body wax mold in the step (3), forming a socket shell through the shell making in the step (4), opening a spigot wax mold on the side surface of the sprue wax mold in the step (3), forming a spigot shell through the shell making in the step (4), and bonding the spigot shell to the outer side of the socket shell.
5. The combined casting process of the large-piece precision casting according to claim 1, characterized in that: and (7) bonding the casting body shell with the sprue shell and the heat-insulating riser in the step 7, and then carrying out heavy pressing along the bonding direction for 10-15 minutes.
6. The combined casting process of the large-piece precision casting according to claim 5, characterized in that: and in the step 7, the casting body shell, the sprue shell and the heat-insulating riser are bonded, and then are ventilated at the outer side while being stressed.
7. The combined casting process of the large-piece precision casting according to claim 1, characterized in that: and (3) communicating the bottom of the sand box in the step (8) with a hot air pipe, connecting the hot air pipe with ventilation equipment, introducing hot air after the pouring is finished, wherein the temperature of the introduced hot air is 50-90 ℃, and the temperature of the introduced hot air is reduced by 5 ℃ every ten minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011532293.XA CN112692234A (en) | 2020-12-23 | 2020-12-23 | Combined casting process of large precision casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011532293.XA CN112692234A (en) | 2020-12-23 | 2020-12-23 | Combined casting process of large precision casting |
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| Publication Number | Publication Date |
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| CN112692234A true CN112692234A (en) | 2021-04-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202011532293.XA Withdrawn CN112692234A (en) | 2020-12-23 | 2020-12-23 | Combined casting process of large precision casting |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114951586A (en) * | 2022-05-30 | 2022-08-30 | 阿诺诗(广东)精密金属科技有限公司 | Cold and hot paste application structure of precision casting and application method thereof |
-
2020
- 2020-12-23 CN CN202011532293.XA patent/CN112692234A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114951586A (en) * | 2022-05-30 | 2022-08-30 | 阿诺诗(广东)精密金属科技有限公司 | Cold and hot paste application structure of precision casting and application method thereof |
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Application publication date: 20210423 |
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| WW01 | Invention patent application withdrawn after publication |