JPH0191935A - Casting mold - Google Patents

Abstract

PURPOSE:To obtain a casting mold having excellent transferability, dimensional stability and heat resistance by using hydraulic material containing cement quality material and slag crushing material as main component and molding. CONSTITUTION:As the cement quality material, each kind of Portland cement, alumina cement, barium cement, mixed cement of fly ash cement and blast furnace slag cement, etc., and mixture of the above cement is used. Then, the mixture of the fly ash and the blast furnace slag does not have hydraulic property in itself but by using it together with many kinds of cement, it is cured. The slag crushing material is the one that the slag by-produced in each kind of metal refining is crushed. The slag by-produced in all kinds of non-ferrous metal refinings without any limitation to the refined metal kind is used. Then, water is added to each kind of blending material to make the kneading material and the casting mold is produced.

Description

[Detailed description of the invention] The present invention relates to a casting mold characterized by using a flexible material.

<Conventional technology and its problems> Conventionally, materials such as sand, metal, ethyl silicate, and 5-silicate have been used as materials for casting molds for various metals such as cast iron, copper alloy, aluminum alloy, and zinc alloy. However, all of these had the disadvantages shown below.

A sand mold that uses sand as a material is a casting mold that is made by hardening fine aggregate such as sand with a composite material.In addition to using thermosetting resin or water glass as a binding material, a sand slurry mixed with water is used after casting. There is also a casting mold called "Nakikomi" which dries. In either case, the bonding material has no heat resistance, so the casting mold itself cannot be heated and molten metal poured into it, and as a result, the casting mold tends to have a poor circulation. Because the sand was transferred, the surface of the cast iron was uneven, and the transfer accuracy of the product was poor.

Since a metal mold using metal as a material is a casting mold manufactured by processing the metal, it has the disadvantage that a complicated shape requires a large number of steps, takes time, and therefore increases the price.

Ethyl silicate! #This is a binder whose main component is ethyl silicate, which is used when performing dense casting, but it is expensive and requires drying and firing (-next and secondary firing) after the molding-hardening-release process. ) It has the disadvantage that it is difficult to use it in large casting molds because it requires a process and its strength after hardening is very low. (Japan Foundry Association Precision Casting Research Department Kanawa, "Precision Casting Method", Nikkan Kogyo Shimbunsha 861-P2S5-167).

Cristobalite as well as stone IF fly silicate,
It is a binding material mixed with silica, etc., and used for ffI dense casting, and it has excellent transfer accuracy of products, but it is 1.30
Since it undergoes thermal decomposition at temperatures above 0°C, it cannot be used as a casting mold for iron, and has the disadvantage that the metals that can be cast are limited. (Ibid. P222-226).

As a result of various studies to solve the above-mentioned drawbacks, the inventors of the present invention found that by using a specific hydraulic material, manufacturing of a casting mold is easy and inexpensive, and the metals that can be cast are limited. However, the present invention was completed based on the knowledge that it is possible to provide a casting mold that has excellent surface transferability and excellent heat resistance including dimensional stability.

Means for Solving the Problems> That is, the present invention is a casting mold made by kneading a hydraulic material whose main components are a cementitious material and a pulverized slurry product.

The present invention will be explained in detail below.

Cementitious substances used in the present invention include various cements, hydraulically active mineral substances, combinations of hydraulically active substances and irritants, and mixtures thereof.

The various cements include ordinary, early strength, ultra early strength, moderate heat, white, and sulfate-resistant Portland cement; alumina cement; barium cement; various types of oil well cement; silica cement, fly ash cement, and blast furnace slag cement. and a mixture of the above cements ff:6 can be obtained.

The hydraulically active mineral substances may include Ca3Si05 mineral substances, Ca3SiO5 mineral solid solutions, and mixtures thereof.

Further, as the substance having hydraulic activity, blast furnace slag,
Fly ash and mixtures thereof can be produced. Although such substances do not have hydraulic properties by themselves, they harden strongly when used in combination with stimulants. Stimulants are conventionally known such as reeds, various cements: calcium hydroxide: calcium oxide;
Quicklime; Calcium aluminate minerals; Various inorganic and organic alkali salts, such as carbonates, bicarbonates, hydroxides, silicofluorides, sodium, lithium, and potassium salts such as gluconic acid and citric acid; gypsum, etc. You can give combinations of more than one species.

The amount of the stimulant varies greatly depending on its type and required performance, but it is 100 parts by weight or less, preferably 60 parts by weight or less, per 100 parts by weight of the substance having hydraulic activity. Among materials having hydraulic activity, blast furnace slag is particularly preferred.

The cementitious material referred to here has an average particle size of 10 to 60.
A size on the order of μm is usually used, but it is of course possible to use a size larger or smaller than this.
not.

In the present invention, the cementitious material is treated with chemicals such as intumescent materials, rapid hardening materials, high-strength admixtures, hardening accelerators, hardening retarders, thickeners, and water reducing agents, which are commonly used in the field of civil engineering and construction. An admixture can also be used in combination if necessary.

The expansion material is an Etrin guide type material, for example, Denki Kagaku Kogyo Co., Ltd. *trade name [C8A #20. J.
Or calcined CaO is preferable, and even among calcined CaO, 1.1
It is generally preferred that the crystal be fired at a temperature of 00 to 1,300°C and have an average crystal diameter of 10 μm or less.

The rapidly hardening materials are preferably calcium aluminate-based materials, such as alumina cement, a combination of alumina cement and gypsum, and parts manufactured by Denki Kagaku Kogyo Co., Ltd.
DENKA

The high-strength admixtures include gypsum-based materials, such as Denki Kagaku Kogyo Co., Ltd.'s component name "Denka Σ10ku0";
Part names such as "Asano Super Mix" manufactured by Nippon Cement Co., Ltd. are effective.

As the hardening accelerator, chlorides such as calcium chloride, thiocyanates, nitrites, chromates, nitrates, etc. are used.

As the hardening retarder, saccharides; soluble dextrin; organic acids such as gluconic acid and their salts; inorganic salts such as hydrogen compounds, and the like can be used.

As the thickener, popal, acrylamide, cellulose ether, methyl cellulose, polyethylene oxide, alyanic acid, casein, etc. can be used.

As the water reducing agent, lignin sulfonate, sodium gluconate, high molecular weight lignin sulfonate, salt of alkylnaphthalene or hexathalene sulfonic acid formaldehyde animal, melamine resin sulfonate, polyacrylate, etc. can be used. This is pulverized slag, which is a by-product. Slag cages are not limited to the type of metal, but are very inexpensive because they are made of cast iron, copper, alloy iron, copper, nickel, lead, tin, etc. These chemical components naturally vary depending on the type of ore, but for example, cast iron and steel slag generally contain 0230-41% by weight, Ca035-45% by weight, MgO3-7% by weight, and MnOO-3-1-1% by weight.
7 weight*? eOO-5~1-7 Jit Yu, At203
Ferrochrome slag, which is a type of ferroalloy, contains 10 to 20% by weight, and is a general KMgO25 to 36%.
j[t%, 810g 25~35''jL quantity, At
! 10323-30 wt%, CrJO33-0-3
-23 weight t '16 s CaOO-2~1-8 weight q
b, lFe0 [1.5% by weight, MnOO-2% by weight,
Contains Nano O-2 weight % IK, OO-1 weight %, etc. The mineral content also varies depending on the type of ore, but for example, cast iron and steel slags are mainly composed of silicates, so the state of the slag changes from crystalline to glassy as the cooling rate increases. Delenai if crystalline)
(2cao・11203・Sing), anorthite (CaO'At203'' 2SiOs+), etc. Also, the slag of 7Erochrome contains spinel (Mg
O・AZ、、O、、) is the main component, and 7 orsterraites (2
Mgo-s10tl], enstatite (1Feo-8
101), Magneto 7 Elite (MgO-FJO3)
These slags are hard and stable substances with a Mohs hardness of 7 to 8, containing hertzite (1Feo'' A408I) and the like. It exhibits a low coefficient of thermal expansion equivalent to that of refractory aggregate, and is most suitable for use in casting molds in terms of performance and economy.These pulverized slag products are adjusted to a specified particle size.The particle size is Considering the transfer accuracy, 5
1! It is preferably about II or less. It is preferable to use 2,000 parts by weight of the pulverized slag product per 100 parts by weight of the cementitious material. If it exceeds 2,000 parts by weight, the amount of cementitious material decreases significantly, making it difficult to obtain a good transfer surface. However, this does not apply when special construction methods such as pre-packed or post-packed construction methods are used.

In the present invention, water is added to the various blended materials to form a kneaded product, and a casting mold is manufactured. The amount of water used is 12 to 3.00 parts by weight per 100 parts by weight of cementitious material.
0 parts by weight is preferred. If it is less than 12 parts by weight, it cannot be made into a mixed material, and if it exceeds 3,000 parts by weight, material separation of water, cementitious material and pulverized slag occurs, and the mixed material cannot be made into a casting mold.

In addition to the above-mentioned materials, various types of fibers can also be used as reinforcing materials in the present invention.

Natural or synthetic mineral fibers, carbon #! Examples include fiber, glass fiber, and natural or synthetic organic fibers such as polypropylene, vinylon, acrylonitrile, and cellulose. It is also possible to use other conventionally used reinforcing materials such as steel rods and FRP rods. In particular, various types of fibers are effective in preventing cracks caused by thermal shock in casting molds.

There are no particular restrictions on the kneading method or order of addition, as long as the above materials are kneaded uniformly.

The method for producing the casting mold is not particularly limited and any conventional method may be used, including a method in which vibration is applied to the kneaded material during pouring in order to ensure good transferability.

The casting mold produced from the kneaded material is cured, but there are no particular restrictions on the curing conditions. However, if a large amount of moisture remains in the casting mold during metal casting, the moisture can cause a steam explosion or gas generation, causing problems in terms of safety and product quality. It is necessary to thoroughly dry the product using a burner or the like to completely evaporate any water that may have an adverse effect.

The structure of the casting mold according to the present invention includes a socket, a sprue, a sprue bottom, a runner, a runner light, a sprue, a sprue, etc.
It is also possible to incorporate gas vents, risers, chillers, etc.

Cast metals include cast irons such as tough cast iron, wear-resistant cast iron, chilled cast iron, and spheroidal graphite cast iron; @: Alloy iron: copper alloys such as bronze, aluminum bronze and steel Aluminum alloys and zinc alloys such as silicon master alloys, aluminum-nickel master alloys, and aluminum-manganese master alloys can be used.

Further, as a casting method, in addition to the usual casting method using gravity, various methods such as a lost wax method, a die-casting method, a centrifugal casting method, and a vacuum casting method are possible.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Using the formulations shown in Table 1, a gear-shaped casting mold shown in FIG. 1 and a cylindrical specimen with a bottom radius of 6 mm and a length of 15 mm for thermal expansion and loss measurement were manufactured. After manufacturing, the casting mold and specimen were dried at 150°C for one day, and then the product surface of the casting mold and the specimen (i-casing were thoroughly heated with acetylene in a burner to dehydrate the hydration water on the surface). Ta.

These casting molds were filled with molten low melting point alloys (ZAS,
The results of pouring aluminum (mA 670°C) and cast iron (melting point approximately 1,300°C) ft.
Shown in the table.

Further, the measurement results of thermal expansion and contraction of these specimens are shown in FIG.

It has been found that the casting mold according to the present invention exhibits a stable thermal expansion force, and that a good product with excellent surface transferability and dimensional accuracy can be obtained no matter which metal is cast, such as S1 aluminum cast iron.

Example 2 The wax model for precision mechanical parts shown in Fig. 6 has a thickness of 10 mm on the surface.
A hydraulic material having the formulation shown in Table 2 was applied with a brush. After 6 hours, after the hydraulic material had sufficiently hardened, the model was heated in a 1,000°C oven for 0.10 minutes to dewax. Molten cast iron (melting point: approximately 1.300'C) was poured into the casting mold of the present invention thus produced to obtain a precision mechanical part. The finished precision mechanical parts were of good quality with excellent surface transferability and dimensional accuracy.

Table 2 <Materials used> Thickening*I Methyl cellulose. "Metrose 90HJ (Shin-Etsu Chemical Co., Ltd.) Water curing accelerator; Lithium carbonate (reagent): Citric acid (reagent)
=0.06: 0.02 Other aspects are the same as in Example 1 <Effects of the Invention> According to the present invention, the production of a casting mold is simple and inexpensive, the product material represented by cast metal is not limited, and the surface It is possible to provide a casting mold with excellent transferability and heat resistance including dimensional stability.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a gear-shaped casting mold. FIG. 2 shows thermal expansion and contraction curves of Examples and Comparative Examples. The solid line shows the curve of Experiment I61, which is a comparative example, and the dotted line shows the curve of Experiment I61, which is an example. FIG. 3 is a schematic diagram of a wax model for precision mechanical parts. 1... Sprue 2... Runner 3... Product portion patent applicant Denki Kagaku Kogyo Co., Ltd. Figure 3

Claims (1)

[Claims] (1) A casting mold made by kneading a hydraulic material whose main components are cementitious material and pulverized slag.