CN112170780A - Machining process for casting with double-layer structure - Google Patents
Machining process for casting with double-layer structure Download PDFInfo
- Publication number
- CN112170780A CN112170780A CN202011009519.8A CN202011009519A CN112170780A CN 112170780 A CN112170780 A CN 112170780A CN 202011009519 A CN202011009519 A CN 202011009519A CN 112170780 A CN112170780 A CN 112170780A
- Authority
- CN
- China
- Prior art keywords
- casting
- optimization
- sand
- hole
- shell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/08—Features with respect to supply of molten metal, e.g. ingates, circular gates, skim gates
- B22C9/082—Sprues, pouring cups
-
- 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
- B22C9/24—Moulds for peculiarly-shaped castings for hollow articles
Abstract
The invention relates to the technical field of investment casting, in particular to a double-layer structure casting processing technology which can ensure the product quality and comprises the following steps of casting structure optimization, gating system optimization and shell making technology optimization, wherein the casting structure optimization comprises the following steps: (1) a casting process hole is formed in the part, and an assembling and positioning step is made; (2) manufacturing a cover for sealing the casting process hole, wherein the cover is matched with the assembling and positioning step and is provided with a welding groove; (3) assembling and welding the cover on the casting process hole; (4) trimming the protruding position at the welding groove; the gating system is optimized to design a plurality of pouring channels into an integral special pouring channel; the shell making process comprises the following optimization steps: (1) sand is poured into the holes; (2) sealing holes by using a ethyl silicate-mullite powder repairing material; (3) and (5) drying the mould shell.
Description
Technical Field
The invention relates to the technical field of investment casting, in particular to a machining process of a double-layer structure casting.
Background
At present, for a double-layer structure casting, due to the structural particularity, in the actual production, according to a conventional shell making method, silica sol slurry of an inner cavity blind hole of the double-layer structure casting is not easy to completely cover and adhere to the surface of a wax mold in the shell making process, sand grains generate a bridging phenomenon in the blind hole during sand pouring, so that an inner mold shell in the hole is difficult to dry, the strength of the mold shell is insufficient, the high-temperature resistance is poor, the mold shell is easy to crack during pouring, a large batch mold leakage phenomenon occurs in the pouring process, the proportion reaches about 60%, the working difficulty of post-cleaning is increased, and the appearance quality of the casting is seriously influenced.
Disclosure of Invention
In order to solve the problem of poor quality of the existing castings, the invention provides a machining process for castings with double-layer structures, which can ensure the product quality.
The technical scheme is as follows: the machining process of the double-layer structure casting is characterized by comprising the following steps of casting structure optimization, gating system optimization and shell making process optimization:
(1) a casting process hole is formed in the part, and an assembling and positioning step is made;
(2) manufacturing a cover for sealing the casting process hole, wherein the cover is matched with the assembling and positioning step and is provided with a welding groove;
(3) assembling and welding the cover on the casting process hole;
(4) trimming the protruding position at the welding groove;
the gating system is optimized to design a plurality of pouring channels into an integral special pouring channel;
the shell making process comprises the following optimization steps:
(1) sand is poured into the holes;
(2) sealing holes by using a ethyl silicate-mullite powder repairing material;
(3) and (5) drying the mould shell.
The method is further characterized in that in the optimized step (1) of the shell making process, the sand filling in the hole is as follows: pouring 80-120 meshes of sand into the groove after four layers of shells are manufactured, pouring a small amount of sand for many times, and continuously shaking to compact;
in the optimized step (3) of the shell making process, the drying time of the surface layer-4 layers is 22-24 hours, so that the shell in the hole is fully dried before sand filling, the shell is dried for more than 4 hours after sand filling and sealing, and the drying time of the 5 layers-the strengthening layer is 8-12 hours.
After the invention is adopted, the casting process hole is formed, the length of the inner cavity of the double-layer casting is changed, and the bent blind hole structure is changed, so that the shell making material can enter the structure more easily, the risks that the coating is not easy to bond at the root part of the blind hole and the sand hole is bridged are reduced, the quality of the mould shell is improved, and the sand cleaning efficiency of the inner cavity is improved; after the gating system is optimized, the shrinkage cavity and shrinkage porosity of a casting are improved, the time of splicing a runner at a wax mold working section is shortened, and the time of wax mold group number is prolonged; the appearance quality of the casting is improved after the shell making process is optimized.
Drawings
FIG. 1 is a schematic view of a casting structure optimization process;
FIG. 2 is a schematic view of an integral dedicated runner;
FIG. 3 is a schematic diagram of simulation results, shell-making conditions and appearance of castings after optimization of the shell-making process.
Detailed Description
A processing technology for a double-layer structure casting comprises the steps of casting structure optimization, gating system optimization and shell manufacturing technology optimization, and is shown in figure 1, and the casting structure optimization steps are as follows:
(1) a casting process hole is formed in the part, and an assembling and positioning step is made;
(2) manufacturing a cover for sealing the casting process hole, wherein the cover is matched with the assembling and positioning step and is provided with a welding groove;
(3) assembling and welding the cover on the casting process hole;
(4) and (5) finishing the protruding position at the welding groove.
The casting process hole is formed, so that the long and bent blind hole structure of the inner cavity of the double-layer casting is changed, the shell making material can enter the structure more easily, and the risks that the coating is not easy to bond at the root of the blind hole and bridging in a sand hole are reduced; the quality of the formwork is improved, and the sand removing efficiency of the inner cavity is improved; before the casting structure is changed, in the process of the post-cleaning operation, the bonded sand at the bottom of the blind hole is difficult to clean, and part of the formwork after the hanging, rolling and sand blasting operations is difficult to clean, so that the time and the labor are consumed; after the fabrication hole is opened, the residual formwork at the bottom can be easily knocked off through the fabrication hole, and then sand blasting operation is carried out, so that the formwork cleaning efficiency is greatly improved.
The existing scheme of the number of groups of splicing runners is adopted, each group of trees consumes about 15 minutes, the welding time of wax pattern workers is increased, the production efficiency is reduced, the capacity of the wax pattern tree is severely limited, the welding positions of the splicing runners are too many, the risk of welding seams generated when the trees are combined is increased, the risk of slag inclusion generated during pouring is also increased, the prediction results of shrinkage cavity and shrinkage porosity of the simulation scheme are displayed by taking the porosity of 2.5%, the phenomena of shrinkage cavity and shrinkage porosity of a bent pipe part of a casting are generated, overheating is caused due to the fact that a blind hole is blocked by a formwork in the actual production process, particularly the risk of shrinkage porosity generated at the bottom of the blind hole is large, the repair ratio is high, and the rejection rate is increased.
Referring to fig. 2, in the present invention, the gating system is optimized to design a plurality of runners as an integral dedicated runner; the tree forming efficiency is remarkably improved, the tree forming time of each piece is reduced to 5 minutes from the original 15 minutes, the welding of wax molds is reduced, the risk of slag inclusion of a casting due to a naturally occurring welding seam is greatly reduced, an inner pouring gate is properly enlarged, the feeding effect is enhanced, the porosity is displayed by 2.5%, and the phenomena of shrinkage cavity and shrinkage porosity do not occur at the bent pipe part of the casting.
Silica sol can not be uniformly coated in blind holes in the existing shell making process, slurry accumulation and part of coating-unattached part can not be quickly and effectively found, sand grains in the holes are seriously bridged during sand spraying, so that the strength in the holes of the formwork is insufficient, and the formwork from 5 layers to a strengthening layer is difficult to dry, so that the air permeability and the high-temperature resistance of the formwork are poor, and the high-proportion mold leakage phenomenon in the pouring process is caused.
As shown in FIG. 3, the shell-making process of the present invention has the following optimization steps:
(1) sand is poured into the holes; pouring 80-120 meshes of sand into the groove after four layers of shells are manufactured, wherein the sand cannot be filled in the groove at one time, and is poured in a small amount of sand for multiple times and is continuously shaken to be solid;
(2) sealing holes by using a ethyl silicate-mullite powder repairing material;
(3) drying the shuttering for a long time, wherein the drying time of the surface layer-4 layers is changed from the original 8-12 hours to 22-24 hours, the shuttering in the hole is fully dried before sand filling, the drying is carried out for more than 4 hours after sand filling and sealing, and the drying of the 5 layers-strengthening layers is carried out according to the normal 8-12 hours. The cast product has good appearance quality.
The advantages of the present invention are summarized below.
1. After the casting structure is optimized:
a) the casting process hole is formed, so that the long and bent blind hole structure of the inner cavity of the double-layer casting is changed, the shell making material can enter the structure more easily, and the risks that the coating is not easy to bond at the root of the blind hole and bridging in a sand hole are reduced;
b) the quality of the formwork is improved, and the sand removing efficiency of the inner cavity is improved; before the casting structure is changed, in the process of the post-cleaning operation, the bonded sand at the bottom of the blind hole is difficult to clean, and part of the formwork after the hanging, rolling and sand blasting operations is difficult to clean, so that the time and the labor are consumed; after the fabrication hole is opened, the residual formwork at the bottom can be easily knocked off through the fabrication hole, and then sand blasting operation is carried out, so that the formwork cleaning efficiency is greatly improved.
2. After the gating system is optimized:
a) the casting shrinkage cavity and shrinkage porosity are improved by optimizing a pouring system, and the yield is improved to 28% from 23%;
b) the time of the splicing pouring gate of the wax mold working section is saved, and the time of the number of wax molds is prolonged.
3. After the shell making process is optimized:
a) when the small batch verification is carried out, no mold leakage exists in the casting holes, and the quality of the mold shell is improved; the mold leakage rate in the casting holes in batch production is reduced from about 60% to about 5%, and the effect is obvious;
b) the appearance quality of the casting is improved: after the process hole opening measure and the sand filling measure in the four-layer back hole of the shell are adopted, the sand filling process of the formwork is adopted, the inner hole of the formwork is not blocked, the formwork in the hole can be fully dried, the shot blasting time is greatly shortened while the mold leakage rate is reduced, and the formwork can be easily cleaned; the mould shell without removing the root part of the blind hole can be easily knocked off through the fabrication hole; the shot blasting time is shortened, and the risks of bruising and orange peel defects in the shot blasting process are reduced.
Claims (3)
1. The machining process of the double-layer structure casting is characterized by comprising the following steps of casting structure optimization, gating system optimization and shell making process optimization:
(1) a casting process hole is formed in the part, and an assembling and positioning step is made;
(2) manufacturing a cover for sealing the casting process hole, wherein the cover is matched with the assembling and positioning step and is provided with a welding groove;
(3) assembling and welding the cover on the casting process hole;
(4) trimming the protruding position at the welding groove;
the gating system is optimized to design a plurality of pouring channels into an integral special pouring channel;
the shell making process comprises the following optimization steps:
(1) sand is poured into the holes;
(2) sealing holes by using a ethyl silicate-mullite powder repairing material;
(3) and (5) drying the mould shell.
2. The machining process for the double-layer structure casting according to claim 1, wherein in the shell making process optimization step (1), sand filling in the hole is specifically as follows: and pouring 80-120 meshes of sand into the groove after four layers of shells are manufactured, pouring a small amount of sand for many times, and continuously shaking to compact.
3. The machining process of the casting with the double-layer structure according to claim 1, wherein in the optimization step (3) of the shell manufacturing process, the drying time of the surface layer-4 layers is 22-24 hours, so that the inner formwork of the hole is fully dried before sand filling, the sand filling and sealing are carried out for more than 4 hours, and the drying of the 5 layers-the strengthening layer is carried out for 8-12 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011009519.8A CN112170780A (en) | 2020-09-23 | 2020-09-23 | Machining process for casting with double-layer structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011009519.8A CN112170780A (en) | 2020-09-23 | 2020-09-23 | Machining process for casting with double-layer structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112170780A true CN112170780A (en) | 2021-01-05 |
Family
ID=73955952
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011009519.8A Pending CN112170780A (en) | 2020-09-23 | 2020-09-23 | Machining process for casting with double-layer structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112170780A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113606185A (en) * | 2021-08-31 | 2021-11-05 | 东营一诚精密金属有限公司 | Closed impeller structure convenient to investment casting |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1827256A (en) * | 2006-04-14 | 2006-09-06 | 清华大学 | Method for direct production of core in narrow groove and blind hole of wax mould |
| CN101480697A (en) * | 2008-01-11 | 2009-07-15 | 上海中洲特种合金材料有限公司 | Case-making method of silicasol investment casting with elongated hole structure |
| CN201428608Y (en) * | 2009-06-18 | 2010-03-24 | 宜兴优纳特机械有限公司 | Routs blower end cover integral-type cast fully-closed water jacket cooling structure |
| CN102773412A (en) * | 2012-08-16 | 2012-11-14 | 安徽应流集团霍山铸造有限公司 | Shell making method for deep blind hole of precision casting |
| CN104043777A (en) * | 2014-06-30 | 2014-09-17 | 薛铁山 | Investment casting method |
| US20170028460A1 (en) * | 2015-07-29 | 2017-02-02 | Castem Co., Ltd. | Method for manufacturing casting using lost wax process |
| CN107838373A (en) * | 2017-11-09 | 2018-03-27 | 西北工业大学 | The complicated closed aluminium alloy box body shell body casting precision casting molding method of ultra-thin-wall |
| CN108080570A (en) * | 2017-12-23 | 2018-05-29 | 石家庄盛华企业集团有限公司 | The middle packing sand technique of leakage in a kind of prevention model casting |
| CN110976772A (en) * | 2019-12-30 | 2020-04-10 | 安徽应流铸业有限公司 | Shell manufacturing method for precisely casting narrow-runner impeller |
-
2020
- 2020-09-23 CN CN202011009519.8A patent/CN112170780A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1827256A (en) * | 2006-04-14 | 2006-09-06 | 清华大学 | Method for direct production of core in narrow groove and blind hole of wax mould |
| CN101480697A (en) * | 2008-01-11 | 2009-07-15 | 上海中洲特种合金材料有限公司 | Case-making method of silicasol investment casting with elongated hole structure |
| CN201428608Y (en) * | 2009-06-18 | 2010-03-24 | 宜兴优纳特机械有限公司 | Routs blower end cover integral-type cast fully-closed water jacket cooling structure |
| CN102773412A (en) * | 2012-08-16 | 2012-11-14 | 安徽应流集团霍山铸造有限公司 | Shell making method for deep blind hole of precision casting |
| CN104043777A (en) * | 2014-06-30 | 2014-09-17 | 薛铁山 | Investment casting method |
| US20170028460A1 (en) * | 2015-07-29 | 2017-02-02 | Castem Co., Ltd. | Method for manufacturing casting using lost wax process |
| CN107838373A (en) * | 2017-11-09 | 2018-03-27 | 西北工业大学 | The complicated closed aluminium alloy box body shell body casting precision casting molding method of ultra-thin-wall |
| CN108080570A (en) * | 2017-12-23 | 2018-05-29 | 石家庄盛华企业集团有限公司 | The middle packing sand technique of leakage in a kind of prevention model casting |
| CN110976772A (en) * | 2019-12-30 | 2020-04-10 | 安徽应流铸业有限公司 | Shell manufacturing method for precisely casting narrow-runner impeller |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113606185A (en) * | 2021-08-31 | 2021-11-05 | 东营一诚精密金属有限公司 | Closed impeller structure convenient to investment casting |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103624218B (en) | A kind of casting method of hollow crankshaft of slurry pump | |
| CN107598097B (en) | Wax mold combination of turbine guide blade and precision casting method thereof | |
| CN203737936U (en) | Fiber-reinforced investment casting composite shell | |
| CN101011724A (en) | Investment casting mold design and motor for investment casting using the same | |
| CN112589049B (en) | Precision casting process based on 3D printing pattern | |
| CN111112552A (en) | Precision casting forming method based on 3D printing technology | |
| CN103372630B (en) | A kind of evaporative pattern production technology of engine cylinder-body | |
| CN110434282B (en) | Mold, tooling and method for core molding of closed impeller sodium silicate sand | |
| CN102909348A (en) | Process for casting gearbox body of centrifugal compressor | |
| CN102601318A (en) | Casting method for thin-wall annular cast | |
| CN110834067B (en) | High-temperature alloy porous seat casting pouring fired mold and fired mold manufacturing process method thereof | |
| CN104014748B (en) | The method utilizing the overall shell mould of formwork roasting apperance gasification, and combustion preparation | |
| CN108746496B (en) | Preparation method of mold shell for investment casting | |
| CN102259165A (en) | Vacuum sealing core making method | |
| CN111531163A (en) | Casting process of motor shell with spiral cooling water channel | |
| CN115283645B (en) | Preparation and application methods of magnesium alloy low-pressure investment casting ceramic shell | |
| CN103658523B (en) | Process method for producing large size sculpture through resin sand removable-flask moulding | |
| CN107962154A (en) | A kind of forming method of large revolving body casting | |
| CN112170780A (en) | Machining process for casting with double-layer structure | |
| CN101637803A (en) | Casting method of wheelside speed reducer casing | |
| CN111761027B (en) | Process method for manufacturing titanium and titanium alloy precision castings through photosensitive resin mold | |
| CN103639358B (en) | The method of lost foam casting anode steel claw and the steel claw white die that is set up | |
| CN105855467B (en) | A kind of hot investment casting wax tube filler inner mold and wax core production method | |
| CN110586874A (en) | Manufacturing method of integral impeller sand core | |
| CN112642992B (en) | Process for improving deformation of circular thin-wall investment casting |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210105 |