JPH0249818B2 - - Google Patents
Info
- Publication number
- JPH0249818B2 JPH0249818B2 JP58151105A JP15110583A JPH0249818B2 JP H0249818 B2 JPH0249818 B2 JP H0249818B2 JP 58151105 A JP58151105 A JP 58151105A JP 15110583 A JP15110583 A JP 15110583A JP H0249818 B2 JPH0249818 B2 JP H0249818B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- core
- casting
- magnesium sulfate
- water
- 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.)
- Expired - Lifetime
Links
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 28
- 238000000034 method Methods 0.000 claims description 18
- 239000002002 slurry Substances 0.000 claims description 12
- 239000010440 gypsum Substances 0.000 claims description 11
- 229910052602 gypsum Inorganic materials 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 238000000465 moulding Methods 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 3
- 239000011819 refractory material Substances 0.000 claims description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 25
- 238000005266 casting Methods 0.000 description 22
- 238000001035 drying Methods 0.000 description 14
- 239000010410 layer Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 9
- 235000019341 magnesium sulphate Nutrition 0.000 description 9
- 239000004576 sand Substances 0.000 description 9
- 239000000377 silicon dioxide Substances 0.000 description 8
- 239000002344 surface layer Substances 0.000 description 5
- 238000005188 flotation Methods 0.000 description 4
- 235000013312 flour Nutrition 0.000 description 4
- -1 alkali metal salt Chemical class 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000004512 die casting Methods 0.000 description 3
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 238000001746 injection moulding Methods 0.000 description 3
- 229910052863 mullite Inorganic materials 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 229910052783 alkali metal Inorganic materials 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 238000005336 cracking Methods 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000011505 plaster Substances 0.000 description 2
- 229910052845 zircon Inorganic materials 0.000 description 2
- GFQYVLUOOAAOGM-UHFFFAOYSA-N zirconium(iv) silicate Chemical compound [Zr+4].[O-][Si]([O-])([O-])[O-] GFQYVLUOOAAOGM-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000010828 elution Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000004688 heptahydrates Chemical class 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
Description
本発明は水溶性の鋳型のうち、特に表層部に硫
酸マグネシウムの結晶微粒子を多く含む緻密層を
形成した鋳型の製造方法に関する。
一般に鋳造法は、重力鋳造法と圧力鋳造法に大
別され、重力鋳造法によつて、中空部を有する製
品或いは複雑形状の製品を鋳造する場合には、珪
砂等を基材とした鋳型（中子を含む）を用いてい
る。例えば中子を用いる場合にあつては、型内に
中子をセツトした後、金属の溶湯を注入し、この
溶湯が凝固した後に中子を崩壊させて取り除き、
所望形状の鋳物製品を得るようにしている。
しかしながら、中子に限らず複雑な形状の鋳型
を使用した場合には、鋳造後の鋳型の取り除きが
面倒で、鋳物内部に珪砂等が残つてしまう不利が
ある。
一方、ダイカスト法などの圧力鋳造によつて中
空状の鋳物を得ようとする場合、前記と同様の珪
砂等を基材とした中子を用いると、先ず強度的に
溶湯圧力に耐えられず、且つ溶湯の差し込みがあ
るため鋳肌も悪くなる不利がある。このため、ダ
イカスト法などにあつては、金属性鋳型（中子）
やNa，Ｋなどを含んだアルカリ金属塩の鋳型
（中子）或いは鋳造後に鋳型（中子）のみを溶出
し得るようにした低融点合金からなる鋳型（中
子）を用いている。
しかしながら、金属性鋳型は引き抜き或いは取
り出し可能な形状としなければならないので複雑
形状の鋳物を製造することができず、またアルカ
リ金属塩の鋳型は強度的に複雑形状のものに適さ
ず、更に、低融点合金の鋳型は加熱溶出時に鋳造
合金と反応して化合物を作り、鋳肌を損う等の欠
点があり実用的でない。
斯る従来の問題点を解決すべく本出願人は先に
特願昭57−62003号（特開昭58―179539）として、
溶湯圧力耐えることができ且つ注水による崩壊性
に優れた鋳型の製造方法を提案した。本発明は特
願昭57−62003号の製造方法の目的に加うるに、
更に成形が極めて容易で作業性の向上を目的とし
てなされたものであり、この目的達成のため本発
明方法は、石こう、硫酸マグネシウムの水和物、
粒状又は粉状の耐火物に水を加えてスラリーとす
る工程と、このスラリーを射出成形して鋳型形状
をした成形物を作る工程と、この成形物を異なる
温度で二段階に乾燥せしめる工程とからなること
をその構成上の特徴としている。
以下に本発明に係る水溶性鋳型の製造方法の一
例を工程順に説明する。
先ず、石こう（CaSO4・１／2H2O）に硫酸マ
グネシウム水和物、例えば７水塩（MgSO4・
7H2O）を混合する。この混合割合は硫酸マグネ
シウムの量が石こうの量よりも多くなるように、
例えば重量比で３：７以上となるようにする。こ
こで、無水硫酸マグネシウムとせず水和物とした
のは、無水硫酸マグネシウムとすると、後にスラ
リーを凝固せしめる際に、無水硫酸マグネシウム
が石こうよりも先に凝固し、フローテーシヨン現
象、つまり混合物中の硫酸マグネシウムの結晶微
粒子が成形物（鋳型）内の水分の移動に伴つて成
形物の最外表面に集まる現象が生じなくなり、後
に硫酸マグネシウムの結晶微粒子を多く含む緻密
な表層部が形成されなくなることによる。また、
硫酸マグネシウム水和物の添加量を石こう以上と
したのは、硫酸マグネシウムの添加量が少ない
と、前記したフローテーシヨン現象が顕著となら
ず、且つ熱間強度が低下することによる。
尚、石こうに添加する硫酸マグネシウム水和物
の水分子数は上記に限らず、１，２，４，５，
６，12等の水分子が結合した水和物を使用するこ
とが可能である。
このように、石こうと硫酸マグネシウム水和物
とからなる混合物に粉末状耐火物と水を加え、次
いで珪砂などの粒状耐火物を混合してスラリーを
生成する。尚、スラリーを生成するにあたつて
は、スラリー中への気泡の巻き込みを極力抑える
べく、静かに撹拌するか、好ましくは減圧下にス
ラリーを置き脱泡するようにし、後の成形物表面
を良好にするようにしてもよい。
以上のようにして得られたスラリーを圧力を加
えて型内に射出成形し、２分〜４分静置すること
で、石こうを凝固せしめた後離型し、目的とする
鋳型形状をなす成形物を得る。このようにして得
られた成形物の強度（抗折力）及び密度と成形圧
力との関係を第１図に示した。第１図から明らか
なように、圧力を加えて射出成形した場合には、
少くとも密度は2.2ｇ／cm3以上となり、流し込み
成形した場合の密度2.0ｇ／cm3程度）と比べ大巾
に密度が向上していることが分る。また密度の向
上に伴つて抗折力も向上し、特に抗折力について
は離型時間が影響することが分る。つまり離型時
間が２分程度では抗折力は約1.5Kg／cm2であるの
に対し、離型時間を10分とした場合には抗折力は
4.5Kg／cm2以上となる。
次に型から取り出した上記成形物を、120℃以
下の乾燥炉にて２時間以上、好ましくは２〜３時
間一次乾燥を行う。ここで一次乾燥温度を120℃
以下としたのは、120℃以上の温度で乾燥せしめ
ると、石こうの水和物（CaSO4・１／2H2O）及
び硫酸マグネシウムの水和物の脱水反応が急激に
発生し、フローテーシヨンによつて生じた鋳型
（成形物）最外表面の緻密な層の通気が悪くなり、
部分的に破裂状態となり、鋳型としての機能を果
たせないことによる。また、乾燥時間を２時間以
上としたのは、第２図にも示すように、表面緻密
層の生成が２時間以下では１mmに満たず、特に乾
燥時間を１時間以下とすると、鋳型中の水分の除
去を充分に行えず、鋳型取出後に変形を生じるこ
とによる。
次いで、一次乾燥が済んだ成形物を更に200℃
以上の温度で二次乾燥せしめる。この二次乾燥の
温度を200℃以上としたのは、200℃以下の温度で
二次乾燥を行うと、石こうの水和物の脱水反応、
即ち、CaSO4・１／2H2O→CaSO4＋１／2H2O
の反応が生じない為、鋳造後に残留結晶水が製品
に悪影響を及ぼすおそれがあることによる。
以上の如くして得られた鋳型の抗折力を他の方
法によつて得たものと比較した結果を第３図に示
す。この図から明らかなように、本発明方法によ
つて得られた鋳型は従来のものに比べ、抗折力に
優れ、鋳込圧力による変形、熱衝撃、熱応力によ
る割れ等の発生がないことが分る。そして、実際
に上記鋳型を中子としてダイカスト鋳造を行つた
結果、鋳造時に中子の変形、割れ、或いは中子表
面への溶湯の差し込みもなく、更に噴射水の洗浄
で容易に崩壊溶出した。
以下に更なる具体例実施例を述べる。
実施例 １
石こう水和物（CaSO4・１／2H2O）6wt％に
硫酸マグネシウム水和物（MgSO4・7H2O）
6.8wt％を混ぜ、この混合物に粉末耐火物として
のムライトフラワー24.4wt％及び水12.8wt％入
れ、更に粒状耐火物としての珪砂（６号相当）
50wt％を入れ、減圧室内で混合してスラリーと
し、このスラリーを型内に約60Kg／cm2の圧力で射
出成形して約２分経過した後、凝固した成形物を
取り出し、直ちに80℃の乾燥炉で３時間一次乾燥
し、その後300℃の乾燥炉で３時間程二次乾燥せ
しめて中子を得た。
得られた中子の構造は第４図に示す如く、３層
から成つており、〔表〕からも明らかなように、
中子１の最外側にはMgSO4の結晶微粒子を多く
含んだ組織的に極めて緻密な表層２が形成され、
この表層２の内側にはMgSO4の含有量が若干少
く、組織的にやや粗くなつた中間層３が形成さ
れ、更に最も内側にはMgSO4の含有量が極めて
少なく、粗い組織の中心層４が形成される。
The present invention relates to a method for manufacturing a water-soluble mold, particularly a mold in which a dense layer containing many crystalline fine particles of magnesium sulfate is formed in the surface layer. Casting methods are generally divided into gravity casting methods and pressure casting methods. When casting products with hollow parts or complex shapes using the gravity casting method, a mold (made of silica sand etc.) is used as a base material. (including the core) is used. For example, when using a core, after setting the core in the mold, molten metal is injected, and after the molten metal solidifies, the core is disintegrated and removed.
The aim is to obtain a cast product with a desired shape. However, when a complex-shaped mold is used, not limited to the core, it is troublesome to remove the mold after casting, and there are disadvantages in that silica sand and the like remain inside the casting. On the other hand, when trying to obtain a hollow casting by pressure casting such as a die casting method, if a core made of silica sand or the like is used as the base material, it will not be strong enough to withstand the pressure of the molten metal. Moreover, since the molten metal is inserted, there is a disadvantage that the casting surface deteriorates. For this reason, in die-casting methods, metal molds (core)
A mold (core) made of an alkali metal salt containing Na, K, etc., or a mold (core) made of a low melting point alloy that allows only the mold (core) to be eluted after casting is used. However, since metal molds must be shaped so that they can be pulled out or taken out, castings with complex shapes cannot be manufactured, and molds made of alkali metal salts are not suitable for complex shapes due to their strength. Molds made of melting point alloys are not practical because they react with the casting alloy during heating and elution to form compounds, damaging the casting surface. In order to solve such conventional problems, the present applicant previously filed Japanese Patent Application No. 57-62003 (Japanese Unexamined Patent Publication No. 58-179539).
We proposed a method for manufacturing molds that can withstand molten metal pressure and have excellent disintegration properties when poured with water. In addition to the object of the manufacturing method of Japanese Patent Application No. 57-62003, the present invention also provides the following:
Furthermore, it is extremely easy to mold and has been developed for the purpose of improving workability.To achieve this objective, the method of the present invention uses gypsum, magnesium sulfate hydrate,
A process of adding water to a granular or powdered refractory to form a slurry, a process of injection molding this slurry to make a molded product, and a process of drying this molded product in two stages at different temperatures. Its structural feature is that it consists of: An example of the method for manufacturing a water-soluble mold according to the present invention will be explained below in order of steps. First, magnesium sulfate hydrate, such as heptahydrate (MgSO 4 .
7H2O ). This mixing ratio is such that the amount of magnesium sulfate is greater than the amount of gypsum.
For example, the weight ratio should be 3:7 or more. Here, the reason we used a hydrate rather than anhydrous magnesium sulfate is that if we use anhydrous magnesium sulfate, when the slurry is solidified later, the anhydrous magnesium sulfate will solidify before the gypsum, resulting in a flotation phenomenon, that is, in the mixture. The phenomenon in which the fine crystalline particles of magnesium sulfate no longer collects on the outermost surface of the molded product due to the movement of moisture within the molded product (mold) occurs, and a dense surface layer containing many fine crystalline particles of magnesium sulfate is no longer formed. It depends. Also,
The reason why the amount of magnesium sulfate hydrate added is greater than that of gypsum is that if the amount of magnesium sulfate added is small, the flotation phenomenon described above will not become noticeable and the hot strength will decrease. The number of water molecules in the magnesium sulfate hydrate added to the plaster is not limited to the above, but may be 1, 2, 4, 5,
It is possible to use a hydrate in which water molecules such as 6 and 12 are bound. Thus, a powdered refractory and water are added to a mixture of gypsum and magnesium sulfate hydrate, and then a granular refractory such as silica sand is mixed in to form a slurry. In addition, when producing the slurry, in order to minimize the inclusion of air bubbles in the slurry, the slurry should be stirred gently or preferably placed under reduced pressure to defoam, and the surface of the molded product afterward should be It may be possible to make it better. The slurry obtained as described above is injection molded into a mold by applying pressure, and left to stand for 2 to 4 minutes to solidify the plaster, which is then released from the mold and molded into the desired mold shape. get something FIG. 1 shows the relationship between the strength (transverse rupture strength) and density of the molded product thus obtained and the molding pressure. As is clear from Figure 1, when injection molding is performed by applying pressure,
It can be seen that the density is at least 2.2 g/cm 3 or more, which is significantly improved compared to the density of about 2.0 g/cm 3 when cast. Furthermore, as the density increases, the transverse rupture strength also improves, and it can be seen that the demolding time particularly affects the transverse rupture strength. In other words, when the mold release time is about 2 minutes, the transverse rupture strength is approximately 1.5Kg/ cm2 , whereas when the mold release time is 10 minutes, the transverse rupture force is approximately 1.5Kg/cm2.
4.5Kg/ cm2 or more. Next, the molded product taken out from the mold is subjected to primary drying in a drying oven at 120° C. or lower for 2 hours or more, preferably 2 to 3 hours. Here, the primary drying temperature is 120℃
The reason for the following is that when dried at a temperature of 120°C or higher, a dehydration reaction of hydrated gypsum (CaSO 4 1/2H 2 O) and hydrated magnesium sulfate occurs rapidly, resulting in flotation. The ventilation of the dense layer on the outermost surface of the mold (molded product) caused by
This is because the mold has partially ruptured and cannot function as a mold. In addition, the reason why the drying time was set to 2 hours or more is because, as shown in Figure 2, the formation of a dense layer on the surface is less than 1 mm in less than 2 hours, and especially if the drying time is 1 hour or less, This is because moisture cannot be removed sufficiently and deformation occurs after the mold is removed. Next, the molded product that has undergone primary drying is further heated to 200℃.
Secondary drying is performed at the above temperature. The reason why the temperature of this secondary drying was set at 200℃ or higher is that if the secondary drying is performed at a temperature of 200℃ or lower, the dehydration reaction of hydrated gypsum will occur.
That is, CaSO 4 1/2H 2 O → CaSO 4 + 1/2H 2 O
Because this reaction does not occur, residual crystallization water may have a negative effect on the product after casting. FIG. 3 shows the results of comparing the transverse rupture strength of the mold obtained as described above with those obtained by other methods. As is clear from this figure, the mold obtained by the method of the present invention has superior transverse rupture strength compared to conventional molds, and there is no occurrence of deformation due to pouring pressure, thermal shock, cracking due to thermal stress, etc. I understand. As a result of actual die casting using the above-mentioned mold as a core, there was no deformation or cracking of the core during casting, no insertion of molten metal into the surface of the core, and the core easily disintegrated and eluted when washed with sprayed water. Further specific examples will be described below. Example 1 Magnesium sulfate hydrate (MgSO 4 7H 2 O) in 6wt% gypsum hydrate (CaSO 4 1/2H 2 O)
6.8wt%, add 24.4wt% of mullite flour as a powdered refractory and 12.8wt% of water to this mixture, and add silica sand (equivalent to No. 6) as a granular refractory.
Add 50wt% and mix in a vacuum chamber to make a slurry. This slurry is injection molded into a mold at a pressure of about 60Kg/ cm2 . After about 2 minutes, the solidified molded product is taken out and immediately placed at 80℃. The core was first dried for 3 hours in a drying oven, and then secondarily dried for about 3 hours in a 300°C drying oven. The structure of the obtained core consists of three layers as shown in Figure 4, and as is clear from the table,
On the outermost side of the core 1, a structurally extremely dense surface layer 2 containing many crystalline particles of MgSO 4 is formed.
Inside this surface layer 2, an intermediate layer 3 with a slightly low content of MgSO 4 and a slightly rough texture is formed, and furthermore, on the innermost side, a central layer 4 with an extremely low content of MgSO 4 and a rough texture is formed. is formed.
【表】
そして、上記中子を型内にセツトし、単気筒の
シリンダポートを、射出圧力600Kg／cm2、Al合金
の溶湯温度を700℃としてダイカスト鋳造したと
ころ、差し込みの全くない良好な鋳肌の製品が得
られた。また、鋳造後の中子の排除には20Kg／cm2
の圧力で60℃の温水を噴出せしめたところ容易に
中子は崩壊溶出した。
実施例 ２
石こう水和物（CaSO4・１／2H2O）10wt％、
硫酸マグネシウム（MgSO4・7H2O）15wt％、
ムライトフラワー21wt％、珪砂45.5wt％及び水
8.5wt％を原料として、前記実施例１と同様の条
件で、自動車用シリンダブロツク鋳造用の中子を
製造した。
この中子を型にセツトし、射出圧力240Kg／cm2、
Al合金（ADC12相当）の溶湯温度730℃の条件で
前記自動車用シリンダブロツクを鋳造したとこ
ろ、溶湯の差し込みが全くなく、外観も良好な鋳
肌をもち、且つ内部も健全な製品が得られた。
尚、以上は本発明の実施の一例に過ぎず、添加
する耐火物はムライトフラワー、珪砂に限らず、
ジルコンフラワー、シリカフラワー、ジルコンサ
ンド、アルミサンド等の金属酸化物、及び金属粒
子を使用しても前記と同様の効果を得ることがで
き、また、本発明方法によつて得られた中子等の
鋳型は圧力鋳造法に限らず重力鋳造法にも好適す
るものである。
以上に説明したように本発明によれば、石こ
う、耐火物等とともに硫酸マグネシウムの水和物
からなる鋳型形状に成形された成形物を二段階に
乾燥せしめ、成形物表面にフローテーシヨンによ
つて硫酸マグネシウムの微細結晶を多く含む緻密
層を形成し、内部を比較的粗い組織となるように
したので、従来の如く中子（鋳型）表面にコーテ
イングを施すことなく、鋳肌の良好な製品を得る
ことができる。
また前記成形物を成形するにあたり、射出成形
を用いるようにしたので、成形物自体の抗折力及
び密度が向上するため鋳造時の圧力に充分耐え、
溶湯の差し込みもなく、成形時間の短縮が図れる
とともに成形物の精度も向上する。したがつて製
品自体の寸法精度を高めることもできる等多くの
効果を発揮する。[Table] Then, the above core was set in a mold and a single-cylinder cylinder port was die-cast at an injection pressure of 600 kg/cm 2 and a molten Al alloy temperature of 700°C. A skin product was obtained. In addition, 20Kg/cm 2 is required to remove the core after casting.
When hot water of 60℃ was jetted out at a pressure of Example 2 Gypsum hydrate (CaSO 4 1/2H 2 O) 10wt%,
Magnesium sulfate (MgSO 4 7H 2 O) 15wt%,
Mullite flower 21wt%, silica sand 45.5wt% and water
Using 8.5 wt% as a raw material, a core for casting an automobile cylinder block was manufactured under the same conditions as in Example 1 above. This core was set in a mold and the injection pressure was 240Kg/cm 2 .
When the above-mentioned automobile cylinder block was cast at a molten Al alloy (equivalent to ADC12) temperature of 730°C, a product with no molten metal penetration, a good cast surface appearance, and a sound interior was obtained. . The above is only an example of the implementation of the present invention, and the refractory to be added is not limited to mullite flour and silica sand.
The same effects as above can be obtained by using metal oxides and metal particles such as zircon flour, silica flour, zircon sand, and aluminum sand, and the cores etc. obtained by the method of the present invention can also be used. The mold is suitable not only for pressure casting but also for gravity casting. As explained above, according to the present invention, a molded product formed into a mold shape made of hydrated magnesium sulfate together with gypsum, refractories, etc. is dried in two stages, and the surface of the molded product is coated with flotation. As a result, a dense layer containing many fine crystals of magnesium sulfate is formed, and the inside has a relatively coarse structure.As a result, products with a good casting surface can be produced without applying a coating to the surface of the core (mold) as in the past. can be obtained. In addition, since injection molding is used to mold the molded product, the transverse rupture strength and density of the molded product itself are improved, so it can withstand the pressure during casting, and
There is no need to insert molten metal, which reduces molding time and improves the precision of the molded product. Therefore, it exhibits many effects such as being able to improve the dimensional accuracy of the product itself.
第１図は成形圧力と抗折力及び密度との関係を
示すグラフ、第２図は乾燥時間と表面緻密層の厚
さとの関係を示すグラフ、第３図は乾燥温度と抗
折力との関係を示すグラフ、第４図は中子の断面
図である。
尚、図面中１は中子、２は表層、３は中間層、
４は中心層である。
Figure 1 is a graph showing the relationship between molding pressure, transverse rupture strength and density, Figure 2 is a graph showing the relationship between drying time and the thickness of the surface dense layer, and Figure 3 is a graph showing the relationship between drying temperature and transverse rupture force. A graph showing the relationship, and FIG. 4 is a cross-sectional view of the core. In addition, in the drawing, 1 is the core, 2 is the surface layer, 3 is the middle layer,
4 is the central layer.
Claims (1)
物を含む混合物に水を加えてスラリーとし、この
スラリーを型内に圧力を加えて射出成形して密度
が2.2ｇ／cm3以上の鋳型形状の成形物を作り、次
いでこの成形物を120℃以下の温度で２時間以上
一次乾燥せしめた後、更に200℃以上の温度で二
次乾燥せしめるようにしたことを特徴とする水溶
性鋳型の製造方法。 ２ 前記成形物の離型時間は２分以上としたこと
を特徴とする特許請求の範囲第１項記載の水溶性
鋳型の製造方法。[Claims] 1. Water is added to a mixture containing gypsum, magnesium sulfate hydrate, and refractory material to form a slurry, and this slurry is injection molded by applying pressure in a mold to a density of 2.2 g/cm 3 A water-soluble product characterized in that a molded article having the above mold shape is made, and then this molded article is firstly dried at a temperature of 120°C or lower for 2 hours or more, and then further dried for a second time at a temperature of 200°C or higher. Method for manufacturing sex molds. 2. The method for manufacturing a water-soluble mold according to claim 1, wherein the molding time for releasing the molded product is 2 minutes or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58151105A JPS6044150A (en) | 1983-08-19 | 1983-08-19 | Production of water soluble casting mold |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58151105A JPS6044150A (en) | 1983-08-19 | 1983-08-19 | Production of water soluble casting mold |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6044150A JPS6044150A (en) | 1985-03-09 |
| JPH0249818B2 true JPH0249818B2 (en) | 1990-10-31 |
Family
ID=15511453
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58151105A Granted JPS6044150A (en) | 1983-08-19 | 1983-08-19 | Production of water soluble casting mold |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6044150A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63132745A (en) * | 1986-11-25 | 1988-06-04 | Honda Motor Co Ltd | Production of water soluble casting mold |
| JP4223830B2 (en) * | 2003-02-21 | 2009-02-12 | マツダ株式会社 | Water-soluble casting mold and manufacturing method thereof |
| JP4485343B2 (en) * | 2004-12-24 | 2010-06-23 | トヨタ自動車株式会社 | Method and apparatus for forming water-soluble core |
| JP5176015B2 (en) * | 2008-02-23 | 2013-04-03 | 富山県 | Molding core |
| JP5393344B2 (en) * | 2009-08-24 | 2014-01-22 | 大東工業株式会社 | Water-soluble mold making method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54151508A (en) * | 1978-05-22 | 1979-11-28 | Hitachi Ltd | Gypsum mold |
-
1983
- 1983-08-19 JP JP58151105A patent/JPS6044150A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54151508A (en) * | 1978-05-22 | 1979-11-28 | Hitachi Ltd | Gypsum mold |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6044150A (en) | 1985-03-09 |
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