CN107716871B - Pouring method for negative pressure lost foam casting - Google Patents
Pouring method for negative pressure lost foam casting Download PDFInfo
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- CN107716871B CN107716871B CN201710863609.5A CN201710863609A CN107716871B CN 107716871 B CN107716871 B CN 107716871B CN 201710863609 A CN201710863609 A CN 201710863609A CN 107716871 B CN107716871 B CN 107716871B
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- pouring
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- ingate
- lost foam
- inner part
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Classifications
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- 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
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
Abstract
The embodiment of the invention provides a pouring method for negative pressure lost foam casting, wherein a pouring system adopting the pouring method is open, a casting is produced by adopting the pouring system, and the sectional area ratio of a sprue, a cross runner and an ingate is as sigma F straight: Σ F horizontal: Σ F ═ 1: (1.2-1.4): (1.2-1.4), calculating the inflow rate of the ingate according to the following formula, wherein the inflow rate of the ingate is obtained through calculation, the selection of a K value is critical, the proper K value can obtain the proper inflow rate of the ingate, and pouring is carried out according to the rate, so that the pouring time is shortened to the maximum degree, and the defects of lost foam casting are reduced.
Description
Technical Field
The invention relates to the technical field of lost foam casting, in particular to a pouring method for negative-pressure lost foam casting.
Background
The gating system has great influence on the casting quality of the lost foam, but at present, no systematic perfection theory and empirical formula exist to design the gating system of the lost foam, so that the development of the lost foam technology is greatly limited, the quality of castings can not realize qualitative leap all the time, and the gating system of the lost foam is also obeyed irregularly. The theory of the lost foam casting generally recommends rapid filling and rapid pouring, and shortens the pouring time as much as possible.
Compared with sand casting, all parameters of the pouring system for sand casting are mature, the parameters are directly used for reference in the application of the pouring system for sand casting, and the calculation methods of the parameters are directly applied to the pouring system for lost foam casting, so that the parameters are not suitable;
the lost foam casting process can be numerically simulated by computer software due to excessive factors such as a pattern material, a pattern density, a pattern gas forming amount, coating permeability, a casting temperature and the like, so that the metal filling and solidifying process can be observed, and the optimal section proportion can be guided to realize rapid filling.
Therefore, the lost foam casting and pouring system needs to be designed in a standardized and standardized manner, so that the lost foam casting and pouring system can be widely applied to practical production, and the stability of the quality of lost foam products is improved.
Disclosure of Invention
There is a need for a casting method for negative pressure lost foam casting that effectively shortens the casting time and reduces the lost foam casting defects.
A pouring method for negative pressure lost foam casting, a pouring system adopting the pouring method is open, a casting is produced by adopting the pouring system, and the sectional area ratio of a sprue, a cross runner and an ingate is Sigma F straight: Σ F horizontal: Σ F ═ 1: (1.2-1.4): (1.2-1.4),
the ingate inflow rate is calculated according to the following formula
In the formula:
vinner part: ingate inflow rate (m.s)-1）；
ρ: density of liquid alloy (kg.m)-3) The constant is obtained by inquiring a liquid alloy density table in a mechanical casting manual according to different brands of alloys to be poured;
∑Finner part: sum of gate sectional areas (cm);
k: correcting coefficient, taking 0.55;
∆Ginner partCalculated according to the following formula
In the formula:
∆Ginner part: flow rate of inner gate (kg.s)-1）；
G: the total amount of liquid alloy flowing through the ingate, including the total of the weight of the casting and the weight of the gating system (kg);
tfast speed: the fast pouring time(s), which is constant, is obtained by consulting the density table of the liquid alloy in the machine casting handbook, depending on the alloy to be poured of different grades.
In the invention, the inflow rate of the ingate is obtained by calculation, wherein the selection of the K value is critical, and the proper K value can obtain the proper inflow rate of the ingate, so that pouring is carried out according to the rate, the pouring time is shortened to the maximum extent, and the casting defects of the lost foam are reduced.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
The embodiment of the invention provides a pouring method for negative pressure lost foam casting, wherein a pouring system adopting the pouring method is open, a casting is produced by adopting the pouring system, and the sectional area ratio of a sprue, a cross runner and an ingate is as sigma F straight: Σ F horizontal: Σ F ═ 1: (1.2-1.4): (1.2-1.4),
the ingate inflow rate is calculated according to the following formula 1
In formula 1:
vinner part: ingate inflow rate (m.s)-1）；
ρ: density of liquid alloy (kg.m)-3) Constant, different for different grades of alloy to be cast, by means of a checking machineObtaining a liquid alloy density table in a casting handbook;
∑Finner part: sum of gate sectional areas (cm);
k: correcting coefficient, taking 0.55;
∆Ginner partCalculated according to the following formula 2
In formula 2:
∆Ginner part: flow rate of inner gate (kg.s)-1）；
G: the total amount of liquid alloy flowing through the ingate, including the total of the weight of the casting and the weight of the gating system (kg);
tfast speed: the fast pouring time(s) is constant and is obtained by inquiring a liquid alloy density meter in a mechanical casting manual according to different brands of alloys to be poured;
and the connection port of the ingate and the lost foam casting mold is an ingate, the flow rate of the ingate is the amount of molten metal in the pouring system entering the lost foam casting mold through the ingate in unit time.
The inflow rate of the ingate is the height of the molten metal rising in the filling of the lost foam casting mold in unit time.
For example, the casting system is used for casting cast iron castings produced by the company, the material of the castings is HT300, the total weight of the castings and the weight of the casting system is 1000kg, and the table is looked up tFast speedIs 39s, and is calculated according to the formula 2 to obtainInner partIs 25.6kg.s-1Looking up the table to obtain rho of 7300kg.m-3Calculating sigma FStraight bar、∑FHorizontal bar、∑FInner partAre respectively 3846mm2，5000mm2，5000mm2Substitution of k =0.55 in formula 1 gives vInner partThe inflow rate of the ingate is 0.38m.s-1The method of the invention is adopted to calculate the inflow rate of the ingate, and the casting defects obtained by pouring are obviously reduced according to the rate of mold filling pouring.
Further, the straight pouring channel,The cross-sectional area ratio of the horizontal pouring channel and the inner pouring channel is sigma FStraight bar：∑FHorizontal bar： ∑FInner part=1：1.2：1.2。
Further, the cross-sectional area ratio of the sprue, the runner and the ingate is sigma FStraight bar：∑FHorizontal bar： ∑FInner part=1：1.4：1.4。
Further, the cross-sectional area ratio of the sprue, the runner and the ingate is sigma FStraight bar：∑FHorizontal bar： ∑FInner part=1：1.3：1.3。
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (4)
1. A pouring method for negative pressure lost foam casting is characterized in that: the pouring system adopting the pouring method is open, and the casting is produced by adopting the pouring system, wherein the sectional area ratio of the sprue, the cross gate and the ingate is sigma F straight: Σ F horizontal: Σ F ═ 1: (1.2-1.4): (1.2-1.4),
the ingate inflow rate is calculated according to the following formula
In the formula:
vinner part: ingate inflow rate (m.s)-1）；
ρ: density of liquid alloy (kg.m)-3) The constant is obtained by inquiring a liquid alloy density table in a mechanical casting manual according to different brands of alloys to be poured;
∑Finner part: sum of gate sectional areas (cm);
k: correcting coefficient, taking 0.55;
∆Ginner partCalculated according to the following formula
In the formula:
∆Ginner part: flow rate of inner gate (kg.s)-1）；
G: the total amount of liquid alloy flowing through the ingate, including the total of the weight of the casting and the weight of the gating system (kg);
tfast speed: the fast pouring time(s), which is constant, is obtained by consulting the density table of the liquid alloy in the machine casting handbook, depending on the alloy to be poured of different grades.
2. The pouring method for negative-pressure lost foam casting according to claim 1, characterized in that: the cross-sectional area ratio of the straight pouring channel, the horizontal pouring channel and the inner pouring channel is sigma FStraight bar：∑FHorizontal bar： ∑FInner part=1：1.2：1.2。
3. The pouring method for negative-pressure lost foam casting according to claim 1, characterized in that: the cross-sectional area ratio of the straight pouring channel, the horizontal pouring channel and the inner pouring channel is sigma FStraight bar：∑FHorizontal bar： ∑FInner part=1：1.4：1.4。
4. The pouring method for negative-pressure lost foam casting according to claim 1, characterized in that: the cross-sectional area ratio of the straight pouring channel, the horizontal pouring channel and the inner pouring channel is sigma FStraight bar：∑FHorizontal bar： ∑FInner part=1：1.3：1.3。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201710863609.5A CN107716871B (en) | 2017-09-22 | 2017-09-22 | Pouring method for negative pressure lost foam casting |
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| CN201710863609.5A CN107716871B (en) | 2017-09-22 | 2017-09-22 | Pouring method for negative pressure lost foam casting |
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| CN107716871A CN107716871A (en) | 2018-02-23 |
| CN107716871B true CN107716871B (en) | 2020-02-18 |
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101559482A (en) * | 2009-05-26 | 2009-10-21 | 华南理工大学 | Method for manufacturing magnesium alloy die casting |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4681624A (en) * | 1985-04-26 | 1987-07-21 | Corning Glass Works | Method of filtering molten metals using a monolithic refractory honeycomb filter |
| RU2002549C1 (en) * | 1991-05-05 | 1993-11-15 | Уральский научно-технологический комплекс | Pouring gate system |
| CN102319891B (en) * | 2011-09-13 | 2013-07-10 | 中国科学院金属研究所 | Gating system capable of effectively controlling air entrainment and slag entrainment and design method thereof |
| CN104550890A (en) * | 2014-12-26 | 2015-04-29 | 宁夏共享装备有限公司 | Pouring system for reducing mold filling speed in pouring gate |
| CN105328127A (en) * | 2015-11-27 | 2016-02-17 | 四川南车共享铸造有限公司 | Open type top shower gating system for air cylinder cover |
| CN105798272A (en) * | 2016-04-22 | 2016-07-27 | 湖南湖大三佳车辆技术装备有限公司 | Automobile mold casting cast by compounding alloy gray iron and ordinary gray iron, gating system and casting method |
| CN105798271A (en) * | 2016-04-22 | 2016-07-27 | 湖南湖大三佳车辆技术装备有限公司 | Automobile mold casting cast by compounding ductile iron and gray iron, gating system and casting method |
| CN105772687A (en) * | 2016-04-22 | 2016-07-20 | 湖南湖大三佳车辆技术装备有限公司 | Automobile mold casting compositely casted through cold work die steel and gray iron, pouring system and casting method |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101559482A (en) * | 2009-05-26 | 2009-10-21 | 华南理工大学 | Method for manufacturing magnesium alloy die casting |
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