JPH0890150A - Self-curing mold for cast steel and method for regenerating molding sand - Google Patents

Self-curing mold for cast steel and method for regenerating molding sand

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Publication number
JPH0890150A
JPH0890150A JP23299794A JP23299794A JPH0890150A JP H0890150 A JPH0890150 A JP H0890150A JP 23299794 A JP23299794 A JP 23299794A JP 23299794 A JP23299794 A JP 23299794A JP H0890150 A JPH0890150 A JP H0890150A
Authority
JP
Japan
Prior art keywords
sand
chromite
ceramic
mold
iron
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.)
Granted
Application number
JP23299794A
Other languages
Japanese (ja)
Other versions
JP3268137B2 (en
Inventor
Sanshirou Hatakeyama
参四郎 畠山
Hisashi Yamashita
尚志 山下
Takeshi Otaguro
剛 太田黒
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Heavy Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Heavy Industries Ltd filed Critical Mitsubishi Heavy Industries Ltd
Priority to JP23299794A priority Critical patent/JP3268137B2/en
Publication of JPH0890150A publication Critical patent/JPH0890150A/en
Application granted granted Critical
Publication of JP3268137B2 publication Critical patent/JP3268137B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PURPOSE: To prevent the generation of harmful components from self-curing molds for cast steels, to prevent the burn of molten steel and to effectively regenerate and recover molding sand from this kind of the casting molds. CONSTITUTION: A water-soluble phenolic resin and a hardener are used for the binder of the self-curing molds for cast steels for which a one-process two- sand system is used. Mullite base ceramic sand 8 of spherical grain shapes having grain size of 0.5 to 1.5mm, Knoop hardness of sand grains of >=900 and a grain size constant of <=1.1 is used for the base sand thereof. Chromite sand 9 of a grain size of <0.5mm which can be sieved from the ceramic sand 8 is used for the chromite sand 9 of pocket sand to be used for the thermally severe facing sand. Such molding sand is subjected to removal of the residual resins by a regenerating machine of a scrubbing system by a high-speed revolving rotor. The iron-components of iron beads are simultaneously removed and are classified by a vibration sieve. The coarse grains are reused as ceramic sand and the fine grains of minus sieve are reused by taking out the chromite sand which is a weakly magnetic material by a magnetic separator.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、鋳造工場に於いて1プ
ロセス2サンド方式を用いている鋳鋼用自硬性鋳型と鋳
物砂再生方法に関するものである。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-hardening mold for cast steel and a method for reclaiming foundry sand, which uses a 1-process 2-sand system in a foundry.

【0002】[0002]

【従来の技術】近年、鋳鋼用自硬性鋳型の次期フラン砂
プロセスとして、水溶性フェノール砂プロセスが普及し
つつある。水溶性フェノール砂プロセスは、バインダー
として水溶性フェノール樹脂を粘結剤に有機エステルを
硬化剤として用いており、前記バインダーは鋳物に有害
な硫黄および窒素を含まず、かつ同バインダーで混練さ
れた水溶性フェノール砂は、従来のフラン砂より耐熱性
と熱可塑性が高い鋳型が得られる等の有利性があり、鋳
鋼品の熱間割れ、ガス、介在物等の鋳造欠陥を減少させ
る新しい砂プロセスであるとともに、同バインダーは、
年々、低価格、高強度品への改良が進み、適用拡大が期
待されている。
2. Description of the Related Art In recent years, a water-soluble phenol sand process has become widespread as a next-generation furan sand process for self-hardening molds for cast steel. The water-soluble phenol sand process uses a water-soluble phenol resin as a binder as a binder and an organic ester as a curing agent, the binder does not contain sulfur and nitrogen harmful to castings, and the water-soluble phenol is mixed with the binder. Phenolic sand has advantages such as a mold with higher heat resistance and thermoplasticity than conventional furan sand, and is a new sand process that reduces hot cracking of cast steel products, casting defects such as gas and inclusions. With the same binder,
It is expected that the application will be expanded due to the progress of low price and high strength products year by year.

【0003】鋳鋼用鋳型への水溶性フェノール砂プロセ
スの適用方法としては、鋳物工場の生産形態及び適用砂
種等に応じて、『1プロセス1サンド方式』、『2プロ
セス2サンド方式』、及び『1プロセス2サンド方式』
が用いられ、各々の方式のフローを図6、図7及び図8
に示す。
As a method of applying the water-soluble phenol sand process to a casting steel mold, "1 process 1 sand system", "2 process 2 sand system", and "1 process 2 sand method"
Is used, and the flow of each method is shown in FIG. 6, FIG. 7 and FIG.
Shown in

【0004】図6に示す『1プロセス1サンド方式』で
は、水溶性フェノール鋳型を比較的細粒のセラミック砂
(商品名;セラビーズ、スプレードライ造粒してキルン
焼成した比較的細粒で、高い硬度を有する球形のムライ
トサンド)の単一砂で構成することにより、砂混練、回
収、再生、供給系に於ける砂処理設備の簡素化と造型作
業の機械化を図っている。また、セラミック砂の良好な
耐破砕性により、強力な砂再生による砂の細粒化を防止
し、鋳物廃砂の低減及び砂品質の安定化を図るととも
に、低熱膨張鋳型を実現している。
In the "1 process 1 sand method" shown in FIG. 6, a water-soluble phenol mold is used as a relatively fine particle of ceramic sand (trade name; Cera beads, spray-dried granulated and kiln-fired relatively fine particle, and high). By constructing a single sand of spherical mullite sand with hardness, the sand processing equipment in the sand kneading, recovery, regeneration and supply system is simplified and the molding work is mechanized. Also, due to the good crush resistance of ceramic sand, it is possible to prevent the sand from becoming fine-grained due to strong sand regeneration, to reduce the waste sand of the casting, to stabilize the sand quality, and to realize a low thermal expansion mold.

【0005】図7に示す『2プロセス2サンド方式』で
は、鋳型肌砂としてクロマイト砂にバインダーとして水
溶性フェノール樹脂と有機エステルを用い、裏砂として
珪砂にフラン樹脂とスルホン酸を適用している。この方
式の特徴としては、鋳鋼品質に最も影響する肌砂に水溶
性フェノールクロマイト砂を用いて鋳造欠陥を防ぎ、裏
砂に安価なフラン珪砂を用いて砂費を押さえている。ま
た前記肌砂と裏砂の砂再生方式をプロセス別に対応させ
ている。つまり、強力な再生が必要な水溶性フェノール
バインダーは溶鋼の熱影響で熱分解し易い肌砂に適用
し、再生が容易なフランバインダーは裏砂の熱影響の少
ない箇所に用いている。更に2プロセスの効果として、
鋳込時に肌砂の水溶性フェノールバインダーから生じる
水蒸気を、水蒸気の発生の少ないフランバインダーの裏
砂でカバーしている。
In the "2 process 2 sand method" shown in FIG. 7, a chromite sand is used as a mold skin sand, a water-soluble phenol resin and an organic ester are used as a binder, and a furan resin and a sulfonic acid are applied to silica sand as a back sand. . The characteristics of this method are that water-soluble phenol chromite sand is used for the skin sand that most affects the quality of cast steel to prevent casting defects, and cheap furan silica sand is used for the back sand to reduce sand costs. In addition, the sand reclaiming method for the skin sand and the back sand is adapted to each process. In other words, the water-soluble phenol binder, which requires strong regeneration, is applied to skin sand that is easily thermally decomposed by the heat effect of molten steel, and the furan binder, which is easily regenerated, is used in areas where the back sand has little heat effect. Furthermore, as an effect of two processes,
The steam generated from the water-soluble phenol binder of the skin sand at the time of casting is covered by the back sand of the furan binder, which generates less steam.

【0006】図8に示す『1プロセス2サンド方式』と
しては、適用する鋳物サイズに限定されない方式であ
り、水溶性フェノール鋳型のベースに比較的通気性が良
好で、且つ安価に入手可能な珪砂を用い、熱影響の厳し
い箇所に高価な特殊砂のクロマイト砂をポケットサンド
として用いた最も一般的な方法である。
The "1 process 2 sand method" shown in FIG. 8 is a method which is not limited to the size of the casting to be applied, and has a relatively good air permeability to the base of the water-soluble phenol mold and is available at low cost. Is the most common method using chromite sand, which is expensive special sand, as a pocket sand at locations where heat is severely affected.

【0007】[0007]

【発明が解決しようとする課題】以上のように水溶性フ
ェノール鋳型は、鋳造欠陥が発生しやすい鋳鋼品の品質
向上に適した砂プロセスであるが、既存の方式では下記
の問題点がある。
As described above, the water-soluble phenol mold is a sand process suitable for improving the quality of cast steel products that are prone to casting defects, but the existing methods have the following problems.

【0008】『1プロセス1サンド方式』砂循環系とし
て図6に示す方式は最もシンプルなクローズドシステム
であり、1サンドで鋳型が要求される全ての条件を満足
する必要があるが、以下に述べる問題点がある。一般に
細粒の砂を用いれば焼着は防止できるが、ガス欠陥の懸
念があり、細粒砂ではガス欠陥には対処するが焼着が発
生しやすく、適用範囲は熱容量が小さく凝固の早い小物
品に限定される。また、水溶性フェノール樹脂は約50
%の水分を含み、鋳込時に大量の水蒸気が発生するとと
もに、現在のスプレードライで造粒するセラミック砂
(セラビーズ)は砂粒径が0.1〜0.35mmの比較的
に細粒砂である。よって、小物鋳鋼品への細粒セラミッ
ク砂の適用は可能であるが、大物鋳鋼鋳型への適用は通
気度低下によるガス欠陥が懸念され、前記セラミック砂
はクロマイト砂の様な砂の焼結による溶鋼の差込み防止
機能がなく、肌砂が溶鋼の凝固温度以上となるような熱
影響の著しい箇所では焼着が生じ易い。なお、セラミッ
ク砂に限らず珪砂でも同様なことが言え、砂粒径が大き
くなるほどその傾向は著しくなるため、単一砂による適
用範囲は小物品に限定される。
"1 process 1 sand system" The system shown in FIG. 6 is the simplest closed system for the sand circulation system, and it is necessary to satisfy all the conditions required for the mold with 1 sand. There is a problem. Generally, using fine-grained sand can prevent seizure, but there is a concern of gas defects. With fine-grained sand, gas defects can be dealt with, but seizure easily occurs, and the applicable range is small heat capacity and quick solidification. Limited to goods. In addition, the water-soluble phenolic resin is about 50
% Of water, large amount of water vapor is generated at the time of pouring, and the current spray-dried ceramic sand (Cera beads) is a relatively fine-grained sand with a sand particle size of 0.1 to 0.35 mm. is there. Therefore, although it is possible to apply fine-grained ceramic sand to small cast steel products, application to large cast steel molds may cause gas defects due to reduced air permeability, and the ceramic sand is due to sintering of sand such as chromite sand. There is no function for preventing molten steel from being inserted, and seizure is likely to occur at locations where heat effect is significant, such as skin sand above the solidification temperature of molten steel. The same applies to silica sand as well as to ceramic sand, and the tendency becomes more remarkable as the particle size of sand increases, so the range of application of single sand is limited to small articles.

【0009】『2プロセス2サンド方式』図7に示す方
式で肌砂に水溶性フェノールクロマイト砂を、裏砂にフ
ラン珪砂を適用すると、肌砂はアルカリ性で裏砂は酸性
となり、前記各砂の反応形態が全く異なるために肌裏砂
の分離対策として「つなぎ」を設ける必要があり、造型
作業に手間取るとともに、肌砂に用いる高価なクロマイ
ト砂の使用量が増えるに伴い新砂補充量が増加する。ま
た、大物鋳型では上型の面積が広くなり、造型時に於け
る模型の抜型抵抗や、鋳込時の輻射熱による肌砂層の熱
膨張から肌砂層の落下が懸念され、これら生産性の問題
から適用範囲が中小品に限定される。更に、2プロセス
のため2系列の砂混練設備が必要となり、バインダー供
給設備を含め砂処理設備の設置費用と維持管理が高くな
る欠点がある。
[2 process 2 sand method] When water-soluble phenol chromite sand is applied to the skin and furan silica sand is applied to the back sand by the method shown in FIG. 7, the skin sand becomes alkaline and the back sand becomes acidic, Since the reaction form is completely different, it is necessary to provide a "tie" as a countermeasure for the separation of the sand on the back of the skin, and it takes time for molding work, and the amount of new sand replenished increases as the amount of expensive chromite sand used for skin sand increases. . In addition, the area of the upper mold is large in a large mold, and there is concern that the mold removal resistance of the model during molding and the thermal expansion of the skin sand layer due to the radiant heat during casting may cause the skin sand layer to fall, which is a problem in terms of productivity. The range is limited to small and medium products. Further, since there are two processes, two series of sand kneading equipments are required, and there is a drawback that the installation cost and maintenance of the sand treatment equipment including the binder supply equipment become high.

【0010】『1プロセス2サンド方式』図8に示され
る方式は、通常5号珪砂をベースとした水溶性フェノー
ル鋳型とし、熱影響の過酷な肌砂にポケットサンドとし
てクロマイト砂を適用し、鋳物サイズに制約されない最
も一般的な方式である。欠点としては、強力な砂再生に
より珪砂が破砕される等、鋳物品質および砂再生等に関
係する数々の問題点があり、多少不具合でも前記『1プ
ロセス1サンド方式』及び『2プロセス2サンド方式』
が適用され、鋳鋼品への水溶性フェノール砂プロセスの
普及を阻害している。
"1 process 2 sand system" The system shown in FIG. 8 is usually a water-soluble phenol mold based on No. 5 silica sand, and chromite sand is applied as pocket sand to heat-affected skin sand, It is the most general method that is not limited by size. As a drawback, there are various problems related to casting quality and sand reclamation, such as crushing of silica sand due to strong sand reclamation. Even if there are some problems, the "1 process 1 sand method" and "2 process 2 sand method" are available. ]
Has been applied to prevent the spread of the water-soluble phenol sand process to cast steel products.

【0011】図8に示される1プロセス2サンド方式に
於ける不具合な点は、次の通りである。 (1) 水溶性フェノール砂の残留樹脂が粘り強い。回
収砂には、エステルで固化した粘り強く堅固な水溶性フ
ェノール樹脂が残留している。 (2) 再生砂の残留樹脂が多い場合。水溶性フェノー
ル砂は残留樹脂分と同程度の水分吸湿性があり、再生砂
の残留樹脂が多い場合、吸湿により砂再生が困難となる
ばかりか、梅雨時期などサンドビン内部で棚吊り、フル
イの目詰り等のトラブルが発生し易く、鋳物品質面でも
ガス欠陥の懸念が生じる。また水溶性フェノール砂は、
再生砂の残留樹脂量の増加に比例して砂強度が低下し、
この傾向は砂が吸湿すると著しく加速される。 (3) 回収砂の残留樹脂の除去に強力な再生が必要と
なる。鋳型の必要強度を得るには、水溶性フェノール砂
は従来のフラン砂に比較して約2倍のバインダーが必要
であり、かつ、水溶性フェノール砂は耐熱性の高いこと
も相乗して、解枠後の回収砂には堅固な樹脂が多く残留
し、残留樹脂の除去には強力な砂再生が必要となる。通
常、鋳鋼用アルカリフェノール再生砂の残留樹脂量管理
値は前記(2)項の理由により、従来のフラン再生砂残
留樹脂量管理値の半分の約0.5%程度と厳しく、残留
樹脂の除去には強力な再生が必要となる。また一般にア
ルカリフェノール砂用にロータタイプのスクラビング方
式を用いた砂再生機では、強力再生に必要な高速回転と
してフラン砂用の2倍のエネルギーを設定し、更にアル
カリフェノール砂の残留樹脂量管理値が低く厳しいため
に再生パス回数を増やす目的で多段式再生機が多用され
ている。 (4) 強力な砂再生で珪砂が破砕され易く作業環境が
悪化する。ベース砂に珪砂を用いた場合には強力再生に
より砂の破砕が生じ易く、砂の歩留まりが悪くなる。こ
のことは新砂補充量の増加による砂コストのアップと共
に、破砕砂の増加による産業廃棄物量の悪化が懸念され
る。また、鋳鋼鋳型に用いる珪砂はSK33程度の高い
耐熱性が要求され、一般にSiO2 成分が95〜99%
の高純度の珪砂が用いられる。溶鋼に接した珪砂は熱衝
撃により575℃で石英変態が生じて破砕されやすくな
り、砂回収時には塵肺の懸念が生じると共に、SiO2
含有率の高い珪砂粉塵により作業者への珪肺対策が必要
となる。 (5) 珪砂中より細粒破砕珪砂の除去が必要である。
システムサンドの砂粒度を維持するには、砂再生装置の
後にフルイ、流動槽等を設けて強力な砂再生で破砕した
珪砂を除去する必要がある。 (6) 珪砂とクロマイト砂の分離に高価で強力な磁選
機が必要である。ベース砂として大量に使用した珪砂の
中より一部のクロマイト砂を回収するにあたり、粒度分
布的に珪砂とクロマイト砂は混在する粒度が多く、フル
イでは分級困難であり、20,000ガウス以上の強力
な磁選機が用いられている。この場合の磁選機はシステ
ムサンド全体を処理するために大きな処理能力が必要で
あり大型で高価な設備となる。 (7) 現状の珪砂による鋳物品質の改善には限度があ
る。珪砂を長期間再利用した場合、溶鋼との反応により
低融点の溶鋼珪酸塩(FeSi2 )が生じ、ガス欠陥及
び焼着の原因となる場合がある。また、鋳鋼鋳型用の珪
砂は、粒径、形状、成分等の物性値で適用はほぼ限定さ
れ、一般に入手し易い5号珪砂が多用されている。5号
珪砂の粒度指数はAFS30〜40で通気度は500〜
900であり、大物鋳型の複雑な中子等には鋳型の通気
性不足によりガス抜を施工する必要があり鋳型が繁雑と
なる。より高級な鋳鋼品を求める場合には、鋳型形状と
して通気度、熱膨張量、耐火度等を改善する必要がある
が、前記珪砂を用いている限り原料砂による鋳型の大幅
な改善は期待できない。
The disadvantages of the one-process, two-sand method shown in FIG. 8 are as follows. (1) The residual resin of water-soluble phenol sand is tenacious. In the recovered sand, a viscous, tough and water-soluble phenolic resin solidified with ester remains. (2) When there is a large amount of residual resin in the recycled sand. Water-soluble phenolic sand has a moisture absorption capacity similar to that of residual resin, and if there is a large amount of residual resin in the reclaimed sand, not only will sand reproduction be difficult due to moisture absorption, but also it will be suspended from the sand bin during the rainy season, and it will Trouble such as clogging is likely to occur, and there is concern about gas defects in terms of casting quality. In addition, water-soluble phenol sand
The sand strength decreases in proportion to the increase in the amount of residual resin in recycled sand,
This tendency is significantly accelerated when the sand absorbs moisture. (3) Powerful regeneration is required to remove the residual resin in the recovered sand. In order to obtain the required strength of the mold, water-soluble phenolic sand requires about twice as much binder as conventional furan sand, and water-soluble phenolic sand has a high heat resistance. A large amount of solid resin remains in the recovered sand after the frame, and strong sand regeneration is required to remove the residual resin. Normally, the residual resin amount control value of alkali phenol regenerated sand for cast steel is about 0.5%, which is half of the conventional furan reclaimed sand residual resin amount control value, which is strict due to the reason in the above item (2), and residual resin is removed. Requires strong regeneration. Generally, in sand regenerators that use a rotor-type scrubbing method for alkaline phenol sand, double the energy for furan sand is set as the high-speed rotation required for strong regeneration, and the residual resin amount control value for alkaline phenol sand is set. Because of low and severe, multistage regenerators are often used to increase the number of regeneration passes. (4) Silica sand is easily crushed by strong sand regeneration, and the working environment deteriorates. When silica sand is used as the base sand, crushing of the sand easily occurs due to strong regeneration, and the yield of the sand deteriorates. This may raise the sand cost due to the increase in the amount of new sand replenishment, and may worsen the amount of industrial waste due to the increase in crushed sand. Further, the silica sand used for the cast steel mold is required to have a high heat resistance of about SK33, and the SiO 2 component is generally 95 to 99%.
High-purity silica sand is used. Silica sand in contact with the molten steel easily quartz transformation is crushed occurred at 575 ° C. The thermal shock, with concerns pneumoconiosis occurs during sand reclamation, SiO 2
Due to the high content of silica sand dust, it is necessary for workers to take measures against silicosis. (5) It is necessary to remove fine-grain crushed silica sand from the silica sand.
In order to maintain the sand grain size of the system sand, it is necessary to install a sieve, a fluid tank, etc. after the sand reclamation device to remove the crushed silica sand by powerful sand reclamation. (6) An expensive and powerful magnetic separator is required to separate silica sand and chromite sand. When recovering a part of chromite sand from a large amount of silica sand used as the base sand, silica sand and chromite sand are mixed in a large particle size distribution, which makes it difficult to classify with a sieve and has a strength of 20,000 gauss or more. A magnetic separator is used. The magnetic separator in this case requires a large processing capacity to process the entire system sand, and is a large and expensive facility. (7) There is a limit to the improvement of casting quality by the existing silica sand. When silica sand is reused for a long time, a molten steel silicate (FeSi 2 ) having a low melting point is generated due to a reaction with molten steel, which may cause gas defects and seizure. The application of silica sand for casting steel molds is almost limited by the physical properties such as particle size, shape, composition, etc., and generally available silica sand No. 5 is often used. No. 5 silica sand has a particle size index of AFS 30-40 and air permeability of 500-
Since it is 900, it is necessary to degas the complex core of a large mold due to insufficient air permeability of the mold, which complicates the mold. When a higher grade cast steel product is sought, it is necessary to improve the air permeability, the amount of thermal expansion, the fire resistance, etc. as the mold shape, but as long as the silica sand is used, significant improvement of the mold by the raw material sand cannot be expected. .

【0012】なお、前記(6)項及び(7)項は2プロ
セス2サンド方式の場合にも該当する。
The above items (6) and (7) also apply to the two-process, two-sand method.

【0013】鋳鋼用自硬性鋳型には、造型性、鋳物サイ
ズの適用性、鋳鋼品質、砂再生性等に多くのものが望ま
れるが、従来の前記3方式は、どの方式も以上の欠点を
伴い、鋳鋼用に水溶性フェノール砂プロセスの普及を阻
害している。本発明は、最も実用化が容易な『1プロセ
ス2サンド方式』を改善して前記の従来の方式の問題点
を解決することができる鋳鋼用自硬性鋳型と鋳物砂の再
生方法を提供しようとするものである。
Although many self-hardening molds for cast steel are desired in terms of moldability, cast size applicability, cast steel quality, sand reclaimability, etc., the above-mentioned three conventional methods have the above-mentioned drawbacks. Accordingly, it has hindered the spread of the water-soluble phenol sand process for cast steel. The present invention intends to provide a self-hardening mold for casting steel and a method for reclaiming casting sand, which can solve the problems of the above-mentioned conventional methods by improving the "1 process 2 sand method" which is the most practically applicable. To do.

【0014】[0014]

【課題を解決するための手段】本発明は次の手段を講じ
た。 (1) 本発明の鋳鋼用自硬性鋳型は、1プロセス2サ
ンド方式を用いる鋳鋼用自硬性鋳型において、バインダ
ーに水溶性フェノール樹脂と硬化剤を用い、鋳物砂のベ
ース砂には粒径が0.5〜1.5mmで砂粒のヌープ硬度
が900以上粒径系数1.1以下の球状粒形のムライト
質のセラミック砂を用い、熱的に過酷な肌砂に用いるポ
ケットサンドのクロマイト砂は前記セラミック砂とフル
イ分け可能な0.5mm未満の粒径のクロマイト砂を用い
たことを特徴とする。 (2) また、本発明の鋳物砂の再生方法は、ベースサ
ンドとして粒径が0.5〜1.5mmのセラミック砂と、
ポケットサンドとして粒径が0.5mm未満のクロマイト
砂を用いたアルカリフェノール回収砂を再生するにあた
り、高速回転ロータによる強力スクラビング方式の再生
機を用いて、前記粗粒セラミック砂とクロマイト砂の残
留樹脂を除去するとともに、クロマイト砂の表面に析出
したアイアンビーズの鉄分を取除き、双方の砂を振動フ
ルイにより分級し、フルイ上の粗粒は再生したセラミッ
ク砂として再利用し、フルイ下の細粒は、20000ガ
ウス以上の磁選機により、アイアンビードを析出してい
る中磁性体、鉄分等の強磁性体、および非磁性体の湯道
レンガ屑等を除去し、弱磁性体であるクロマイト砂を取
出し再利用することを特徴とする。
The present invention has taken the following means. (1) The self-hardening mold for cast steel of the present invention is a self-hardening mold for cast steel using a 1-process, 2-sand method, in which a water-soluble phenolic resin and a curing agent are used as a binder, and the particle diameter of the base sand of the foundry sand is 0. Chromite sand, which is a pocket sand used for thermally severe skin sand, is made of spherical mullite ceramic sand having a Knoop hardness of 900 to 1.5 mm and a grain size of 1.1 or less. It is characterized by using chromite sand having a particle size of less than 0.5 mm, which can be separated from ceramic sand by screening. (2) Further, the method for reclaiming foundry sand of the present invention comprises: ceramic sand having a particle size of 0.5 to 1.5 mm as a base sand;
When regenerating the alkali phenol recovered sand using chromite sand with a particle size of less than 0.5 mm as the pocket sand, a strong scrubbing type regenerator with a high-speed rotating rotor was used to remove the residual resin of the coarse-grained ceramic sand and chromite sand. In addition to removing iron, iron particles of iron beads deposited on the surface of chromite sand were classified, and both sands were classified by a vibrating sieve.The coarse particles on the sieve were reused as regenerated ceramic sand, and the fine particles under the sieve were fined. Uses a magnetic separator of 20000 Gauss or more to remove medium magnetic material that is precipitating iron beads, ferromagnetic material such as iron, and non-magnetic material such as runner brick scraps, and remove chromite sand that is a weak magnetic material. The feature is that it is taken out and reused.

【0015】[0015]

【作用】前記(1)の本発明の鋳鋼用自硬性鋳型は、バ
インダーに水溶性フェノールと硬化剤を用いた水溶性フ
ェノール鋳型であり、鋳物砂として用いる耐火性粒状骨
材に粗粒のセラミック砂とクロマイト砂を用いた単純な
鋳型構成であり以下に示す鋳鋼品質の改善が成さる。
The self-hardening mold for cast steel according to the present invention (1) is a water-soluble phenol mold using water-soluble phenol and a hardening agent as a binder, and a coarse-grained ceramic as a refractory granular aggregate used as foundry sand. This is a simple mold composition using sand and chromite sand, which results in the following improvements in cast steel quality.

【0016】 樹脂の作用。 水溶性フェノール樹脂は、硬化剤の有機エステルにより
中和反応で一次固化し、鋳込時の熱でさらに重合硬化が
進み二次固化する。また水溶性フェノール樹脂はベンゼ
ン環を有し熱によりカーボンボンド化しやすいことも伴
い、耐熱性の高い鋳型を形成して焼着の低減、砂の洗わ
れによる砂噛みの低減が期待できる。また、水溶性フェ
ノールと硬化剤を用いた前記バインダーは硫黄を含まな
いために熱間割れが発生しにくく、かつ窒素を含まない
ために窒素に関係するガス欠陥が防止できる。
The action of the resin. The water-soluble phenol resin is first solidified by the neutralization reaction by the organic ester of the curing agent, and further polymerized and cured by the heat at the time of casting to be secondarily solidified. Further, since the water-soluble phenol resin has a benzene ring and is easily carbon-bonded by heat, it is expected that a mold having high heat resistance is formed to reduce seizure and sand trapping due to sand washing. Further, since the binder using the water-soluble phenol and the curing agent does not contain sulfur, hot cracking hardly occurs, and since it does not contain nitrogen, gas defects related to nitrogen can be prevented.

【0017】 クロマイト砂の作用。 特殊砂として、中子及び外型コーナ部等の鋳型温度が例
えば900℃以上となる熱的に厳しい箇所の肌砂にポケ
ットサンドとしてクロマイト砂を適用することにより、
溶鋼と接触するクロマイト砂表面層では、鋳込直後の溶
鋼熱によりスピネル構造のクロマイト砂〔(Fe,M
g)O・(Fe,Cr,Al)2 3 〕中から砂表面に
鉄成分が還元析出する。この現象は、受湯時の高熱で還
元反応を生じクロマイト砂中に25〜29%程度含有す
る鉄分が、金属Feとして粒径2〜20μの汗の状態で
クロマイト砂表面に析出し、通常アイアンビーズと称さ
れている析出物が見受けられる。また、長時間著しい熱
影響を受けたクロマイト砂では、大量のアイアンビーズ
が各々連結して粒径が0.5mm未満(平均粒径150〜
350μが望ましい)のクロマイト砂表面を5〜10μ
厚さの鉄被膜で覆ってしまう。この鉄被膜は砂表面をビ
ード状に形成しアイアンビードと称される。鋳込時には
クロマイト砂からの前記析出物により砂粒間焼結が生
じ、溶鋼に接触したクロマイト砂の最表面層は堅固な鋳
型壁を形成することにより、溶鋼の浸透を抑え焼着を防
止する作用があるとともに、これら析出物により肌砂最
表面層のクロマイト砂粒間空隙率が減少し、肌砂後方か
らの溶鋼へのガス圧をある程度抑え、ガス欠陥を低減さ
せる効果もある。
The action of chromite sand. As a special sand, by applying chromite sand as pocket sand to skin sand at locations where the mold temperature of the core and outer mold corners is 900 ° C. or higher, for example, it is a pocket sand.
In the chromite sand surface layer in contact with molten steel, the chromite sand [(Fe, M
g) Iron components are reduced and precipitated on the sand surface from O. (Fe, Cr, Al) 2 O 3 ]. This phenomenon occurs because the iron content contained in the chromite sand in the extent of 25-29% due to the reduction reaction due to the high heat at the time of receiving hot water is deposited on the chromite sand surface as metallic Fe in the state of sweat having a particle size of 2 to 20 μm, and is usually iron. Precipitates called beads are visible. Also, in chromite sand that has been significantly affected by heat for a long time, a large number of iron beads are connected to each other and the particle size is less than 0.5 mm (average particle size 150-
Chromite sand surface of (350μ is desirable) 5-10μ
Cover with a thick iron coating. This iron coating forms a bead shape on the sand surface and is called an iron bead. During casting, intergranular sintering occurs due to the above-mentioned precipitates from chromite sand, and the outermost surface layer of chromite sand that comes into contact with molten steel forms a solid mold wall, which suppresses penetration of molten steel and prevents seizure. At the same time, these precipitates reduce the porosity between the chromite sand grains in the outermost surface layer of skin sand, suppress the gas pressure from the rear of the skin sand to the molten steel to some extent, and have the effect of reducing gas defects.

【0018】 セラミック砂の作用。 ベースサンドとしてはペレタイザーで造粒された粗粒の
セラミック砂を適用する。前記セラミック砂はカオリン
質原料とアルミナ原料を粉砕混合して、ペレタイザーで
球形に造粒後キルンで高温焼成してムライト化すること
で、熱膨張が少なく、熱変態点のない耐破砕性の良好な
セラミック砂となっており、珪砂のように溶鋼との反応
でガス欠陥および焼着の原因となる溶融珪酸塩(FeS
2 )が生じ難い特長を有す。セラミック砂の粒度設定
としては、「クロマイト砂がフルイ分け可能な程度の粗
粒」「正規分布を示す砂粒度で熱膨張率が少なく、5号
珪砂並の浸透型焼着に対する耐焼着性を有する」ことが
好ましく、粒径が0.5mm未満のクロマイト砂と篩分け
が可能な程度の前記の粗粒のセラミック砂をベースサン
ド砂として用いることにより、溶鋼が接触する鋳型肌砂
からの燃焼ガス及び水蒸気を、後方に逃がすことで溶鋼
に侵入するガスを極力防止してガス欠陥を低減するとと
もに、耐火度が高く低膨張で熱変形の少ない鋳型によ
り、寸法精度の高い鋳鋼品を得ることが可能である。
The action of ceramic sand. As the base sand, coarse-grained ceramic sand granulated with a pelletizer is applied. The ceramic sand is crushed and mixed with a kaolinic raw material and an alumina raw material, pelletized into a spherical shape with a pelletizer, and then fired at a high temperature in a kiln to form a mullite. It is a fine ceramic sand, and like fused silica, it causes gas defects and seizure due to the reaction with molten steel.
i 2 ) is unlikely to occur. As the grain size setting of ceramic sand, "coarse grains that can be sorted by chromite sand""Sand grain size with normal distribution, low thermal expansion coefficient, and seizure resistance against infiltration type seizure like No. 5 silica sand It is preferable that the chromite sand having a particle size of less than 0.5 mm and the above-mentioned coarse-grained ceramic sand that can be sieved are used as the base sand, so that the combustion gas from the mold surface sand that the molten steel comes into contact with Also, by letting water vapor escape backwards, gas that enters the molten steel is prevented as much as possible to reduce gas defects, and a cast steel product with high dimensional accuracy can be obtained by a mold with high fire resistance, low expansion and little thermal deformation. It is possible.

【0019】 樹脂と砂の相乗作用。 前記水溶性フェノール樹脂と有機エステル等の硬化剤を
バインダーとし、耐火性粒状骨材のベースに粗粒のセラ
ミック砂、熱影響の著しい局所にポケットサンドとして
クロマイト砂を適用することにより、高級鋳鋼品の製造
に必要な、低膨張、高通気度で耐熱性の高い鋳型が構成
される。
Synergy of resin and sand. By using the water-soluble phenolic resin and a curing agent such as an organic ester as a binder, and applying coarse ceramic sand to the base of the refractory granular aggregate and chromite sand as the pocket sand where the heat effect is significant, high-grade cast steel products A mold having low expansion, high air permeability, and high heat resistance, which is necessary for the production of, is constructed.

【0020】また、前記(2)の本発明の鋳物砂の再生
方法は、次の作用を有する。
Further, the method (2) of the present invention for reclaiming foundry sand has the following effects.

【0021】 砂の再生が容易。 鋳型基材として、高い硬度のセラミック砂とクロマイト
砂を用いることにより、前記一対の混合回収砂の再生
は、高速回転ロータによる強力なスクラビング方式の再
生機で残留樹脂を除去することで可能である。また、著
しく熱影響を受けたクロマイト砂の表面にはアイアンビ
ーズおよび堅固なアイアンビーズが形成されているが、
このうちアイアンビーズはクロマイト砂の表面に汗の状
態で発生しており、前記、残留樹脂除去時の強力な砂再
生において大部分が除去できる。
Easy to regenerate sand. By using high hardness ceramic sand and chromite sand as the mold base material, it is possible to regenerate the pair of mixed and recovered sands by removing the residual resin with a powerful scrubbing type regenerator using a high-speed rotating rotor. . Iron beads and solid iron beads are formed on the surface of chromite sand that has been significantly affected by heat.
Of these, iron beads are generated in the form of sweat on the surface of the chromite sand, and most of them can be removed by the strong sand regeneration at the time of removing the residual resin.

【0022】 セラミック砂とクロマイト砂の分級が
容易。 ベースの粗粒セラミック砂と特殊砂のクロマイト砂は、
前記のように砂粒度の差を有しており、この砂粒度の差
によって単純な振動フルイで分級が可能となる。このフ
ルイ分級された粗粒のセラミック砂はそのまま再利用可
能であり、細粒砂はクロマイト砂を主成分としている。
Easy classification of ceramic sand and chromite sand. Coarse-grained ceramic sand of base and chromite sand of special sand are
As described above, there is a difference in sand particle size, and this difference in sand particle size enables classification with a simple vibration screen. This sieve-classified coarse-grained ceramic sand can be reused as it is, and the fine-grained sand mainly contains chromite sand.

【0023】 クロマイト砂中の不純物除去が小型の
磁選機で可能。 フルイ分級された細粒砂の構成は下記に示す内容とな
る。 非磁性体:再利用できない破砕湯道スリーブ、破砕セラ
ミック砂、砂表面より剥離した樹脂 弱磁性体:細粒砂の主体であり、熱影響が比較的少なく
変質していない良好なクロマイト砂、及びアイアンビー
ズを除去し再利用可能なクロマイト砂 中磁性体:砂表面層に堅固なアイアンビードが発生して
いる再利用困難なクロマイト砂 強磁性体:溶鋼が付着した砂粒、砂再生でクロマイト砂
表面より剥離したアイアンビーズ、湯玉及び細かな鋳バ
リ等の鉄分 前記細粒砂の主体である弱磁性体は、20,000ガウ
ス以上の強力な磁選機により選別し再利用する。なお、
この時の磁選機の能力は適用クロマイト砂を処理する程
度の小型のもので対応することができる。
Impurities in chromite sand can be removed with a small magnetic separator. The composition of the sieve-classified fine sand is as shown below. Non-magnetic material: crushed runner sleeve that cannot be reused, crushed ceramic sand, resin exfoliated from the sand surface Weak magnetic material: Mainly composed of fine-grained sand, good chromite sand that is relatively unaffected by heat and has not deteriorated, and Chromite sand that can be reused after removing iron beads Medium magnetic material: chromite sand that is hard to reuse with solid iron beads in the sand surface layer Ferromagnetic material: Sand particles with molten steel attached, chromite sand surface by sand regeneration Iron components such as more separated iron beads, hot water balls, and fine cast burrs The weak magnetic material, which is the main component of the fine-grained sand, is selected by a strong magnetic separator of 20,000 gauss or more and reused. In addition,
At this time, the capacity of the magnetic separator can be small enough to process the applicable chromite sand.

【0024】また更に、前記(1)の本発明の鋳鋼用自
硬性鋳型と前記(2)の本発明の鋳物砂の再生方法によ
り、次の作用が奏せられる。
Furthermore, the following effects are exhibited by the self-hardening mold for cast steel according to the present invention (1) and the method for reclaiming foundry sand according to the present invention (2).

【0025】 廃砂の低減 前記のようなセラミック砂を鋳型のベース砂に適用する
ことにより、強力再生による堅固な残留樹脂の除去が可
能となり、砂の細粒化を最小限に止めて歩留まりの改善
と廃砂量の低減が実現できる。
Reduction of Waste Sand By applying the ceramic sand as described above to the base sand of the mold, it becomes possible to remove the solid residual resin by strong regeneration, and to minimize the grain refinement of the sand to improve the yield. Improvement and reduction of waste sand amount can be realized.

【0026】 粉塵の低減 本発明で用いられる珪砂より粗粒のセラミック砂は、珪
砂と異なり破砕し難い点から砂処理作業者への塵肺が改
善される。また、遊離珪酸を含有しないムライトが主成
分のセラミック砂で珪肺を防止できる。
Reduction of Dust Dust, which is coarser than silica sand used in the present invention, is unlikely to be crushed unlike silica sand, which improves the pneumoconiosis to sand processing operators. Further, silicosis can be prevented by using ceramic sand whose main component is mullite containing no free silicic acid.

【0027】[0027]

【実施例】以下、本発明の実施例、以下に説明する。ま
ず、溶鋼品質に大きな影響を与える鋳型からのガス組成
の調査として、表1に示すように、石見5号珪砂を原料
砂とし、フランバインダーおよび水溶性フェノールバイ
ンダーの発生ガス組成の調査を行い、水溶性フェノール
砂からのガス組成には硫黄と窒素のガス成分が無いこと
を確認した。
EXAMPLES Examples of the present invention will be described below. First, as shown in Table 1, Iwami No. 5 silica sand was used as raw material sand to investigate the gas composition of the furan binder and the water-soluble phenol binder, as shown in Table 1, It was confirmed that the gas composition from the water-soluble phenol sand had no sulfur and nitrogen gas components.

【0028】[0028]

【表1】 [Table 1]

【0029】セラミック砂は、クロマイトとフルイ分離
可能な粒度として、図1に示す粒度分布のA、B、Cの
3種類を検討した。まずセラミック砂の粒度選定にあた
り、表2に示すように、比較用セラミック砂B、Cの通
気度は石見5号珪砂より著しく高いが混練砂強度が劣り
造型面で支障をきたすとともに、同セラミック砂B、C
は平均粒径が大きく浸透型の焼着の懸念より適用が困難
と判断された。
As the ceramic sand, three types of particle sizes A, B, and C having the particle size distribution shown in FIG. 1 were examined as the particle sizes capable of separating chromite and sieve. First, in selecting the particle size of the ceramic sand, as shown in Table 2, the air permeability of the comparative ceramic sands B and C is significantly higher than that of Iwami No. 5 silica sand, but the kneading sand strength is inferior and the molding surface is hindered. B, C
It was judged that it was difficult to apply because of the large average particle size and concern about penetration type seizure.

【0030】[0030]

【表2】 [Table 2]

【0031】セラミック砂Aは表2及び表3に示すよう
に石見5号珪砂と比べ、耐火度、粒形、硬度、通気度、
急熱膨張量に優れている。また石見5号珪砂より劣る点
は混練砂強度が若干低く、平均粒径が1.4倍と大きな
ために浸透型焼着に留意する必要があり、図2に示す鋳
型によって鋳造された試験片を用いて耐焼着性の調査を
行ない、表4に示す結果を得た。
As shown in Tables 2 and 3, the ceramic sand A has a fire resistance, a grain shape, a hardness, an air permeability, which are higher than those of Iwami No. 5 silica sand.
Excellent in rapid thermal expansion. Inferior to Iwami No. 5 silica sand, the kneading sand strength is slightly lower and the average particle size is as large as 1.4 times, so it is necessary to pay attention to permeation type seizure, and the test piece cast by the mold shown in FIG. The anti-seizure property was investigated by using, and the results shown in Table 4 were obtained.

【0032】[0032]

【表3】 [Table 3]

【0033】[0033]

【表4】 [Table 4]

【0034】表4によると、セラミック砂Aの耐焼着性
は石見5号珪砂と大差がなく、試験片凸部の熱影響の厳
しい箇所には浸透型の焼着が発生し、平面部は良好な結
果を得た。このことは、粒径が石見5号珪砂より大きい
にもかかわらず、セラミック砂Aの急熱膨張量が少ない
ために最表面の肌砂層の移動が微量で塗型層の破壊が少
なく、表4に示す結果になったものと推定される。
According to Table 4, the seizure resistance of the ceramic sand A is not much different from that of the Iwami No. 5 silica sand, and penetration-type seizure occurs at the heat-affected part of the convex part of the test piece, and the flat part is good. I got good results. This means that although the particle size is larger than that of Iwami No. 5 silica sand, the amount of rapid thermal expansion of ceramic sand A is small, so that the movement of the outermost surface skin sand layer is small and the coating layer is less destroyed. It is highly probable that the results were shown in.

【0035】前記試験結果により実品への適用例を図3
に示す。図3はコンプレッサー車室の鋳鋼鋳型の断面図
であり、バインダーには水溶性フェノール樹脂と硬化剤
を用い、鋳物砂として適用する耐火性粒状骨材に、表
1、表2に示すクロマイト砂とセラミック砂Aを用い、
溶鋼と接触する肌砂の最表面には塗型材を用いている。
An example of application to an actual product based on the above test results is shown in FIG.
Shown in FIG. 3 is a cross-sectional view of a cast steel mold for a compressor casing, in which a water-soluble phenolic resin and a curing agent are used as a binder, and a refractory granular aggregate applied as foundry sand and chromite sand shown in Tables 1 and 2 are used. Using ceramic sand A,
A coating material is used on the outermost surface of skin sand that comes into contact with molten steel.

【0036】図4は本発明の実施例に係るコンプレッサ
ー車室の鋳鋼鋳型の断面図であり、1は鋳枠、2は定
盤、3は鋳型空間部、4は押湯、4−aは押湯保温スリ
ーブ、5は湯道、5−aは湯道スリーブ、6は外型、6
−aは外型肌砂平面部、6−bは外型肌砂凸部、7は中
子、8はセラミック砂、9はクロマイト砂を示してい
る。
FIG. 4 is a sectional view of a cast steel mold for a compressor casing according to an embodiment of the present invention. 1 is a casting frame, 2 is a surface plate, 3 is a mold space portion, 4 is a riser, and 4-a is a Feeder heat retaining sleeve, 5 runner, 5-a runner sleeve, 6 outer mold, 6
Reference numeral -a indicates an outer skin sand flat surface portion, 6-b indicates an outer skin sand convex portion, 7 indicates a core, 8 indicates ceramic sand, and 9 indicates chromite sand.

【0037】熱影響が過酷な鋳型の外型肌砂凸部6−b
と中子7の肌砂には耐焼着性の良好なクロマイト砂9を
全砂の1割程度用い、熱影響が過酷でない外型肌砂平面
部6−aおよび外型6と中子7の裏砂には、ベースサン
ドとしてセラミック砂8を用いる。溶鋼は湯道4を経由
して鋳型空間部3に入り、押し湯4まで注湯するもの
で、セラミック砂8の通気性が良好なことにより、中子
7のガス抜きを廃止したシンプルな高通気度鋳型であ
り、しかも熱膨張の少ない低膨張鋳型を実現することが
できた。
Outer mold skin convex portion 6-b of the mold severely affected by heat
Chromite sand 9 having good seizure resistance is used for the skins of the core and the core 7 in an amount of about 10% of the total sand, and the heat effect is not severe. Ceramic sand 8 is used as the base sand for the back sand. Molten steel enters the mold space 3 via the runner 4 and is poured up to the riser 4, and since the ceramic sand 8 has good air permeability, degassing of the core 7 has been eliminated. It was possible to realize a low-expansion mold that is a breathable mold and that has little thermal expansion.

【0038】また、図4に示す鋳鋼用自硬性鋳型は、バ
インダーに水溶性フェノール樹脂と硬化剤を用い、鋳物
砂のベースサンドとして、粒径が0.5mm〜1.5mmの
範囲で、かつ、砂のヌープ硬度が900以上粒径系数
1.1以下の球状粒径のムライト質のセラミック砂を用
い、熱的に過酷な肌砂に用いるポケットサンドのクロマ
イト砂は、前記セラミック砂とフルイ分け可能な粒径と
し、粒径が0.5mm未満のクロマイト砂を用いた1プロ
セス2サンド方式の鋳型である。
Further, the self-hardening mold for cast steel shown in FIG. 4 uses a water-soluble phenolic resin and a hardening agent as a binder, has a particle size of 0.5 mm to 1.5 mm as a base sand of foundry sand, and , Mullite ceramic sand having a spherical particle size with a Knoop hardness of 900 or more and a particle size number of 1.1 or less is used, and chromite sand of pocket sand used for heat-harsh skin sand is classified into the above-mentioned ceramic sand and a sieve. It is a one-process, two-sand mold using chromite sand with a possible particle size of less than 0.5 mm.

【0039】図5は本発明の実施例に係る鋳物砂の再生
方法を示すものであり、1プロセス2サンド方式のフロ
ー図で砂再生を主体とした砂循環系統の説明図である。
本実施例では、表1、表2に示すクロマイト砂とセラミ
ック砂Aを用いた水溶性フェノール鋳型に鋳鋼を注湯し
て、解枠砂を回収後下記に示す再生を行う。
FIG. 5 shows a method for reclaiming foundry sand according to an embodiment of the present invention, and is a flow chart of the 1-process 2-sand method and is an explanatory view of a sand circulation system mainly for reclaiming sand.
In this example, cast steel is poured into a water-soluble phenol mold using chromite sand and ceramic sand A shown in Tables 1 and 2, and the unfolded sand is recovered and then the following regeneration is performed.

【0040】 解枠砂の再生装置としては、セラミッ
ク砂に一部クロマイト砂が混入した水溶性アルカリフェ
ノール回収砂(残留樹脂量:1.4%)を周速50 m/
secの高速回転ロータによる強力スクラビング方式の再
生機が用いられる。パス回数毎の残留樹脂除去率は23
〜25%/パスであり、パス回数の増加に伴い回収砂の
残留樹脂は除去され、4パスで目標管理値の0.5%と
なる。
As a reclaiming device for the unraveling sand, water-soluble alkali phenol recovery sand (residual resin amount: 1.4%) obtained by mixing chromite sand in ceramic sand is used at a peripheral speed of 50 m /
A powerful scrubbing type regenerator with a high-speed rotor of sec is used. The residual resin removal rate for each pass is 23
It is ˜25% / pass, and the residual resin in the recovered sand is removed with an increase in the number of passes, and becomes 0.5% of the target control value in 4 passes.

【0041】砂硬度が高く粒形の良好なセラミック砂
は、砂再生で砂表面が僅か研磨除去された程度なので、
再生歩留りが0.6%と著しく良好な値を示した。クロ
マイト砂においては、ある程度砂粒の角がとれると、砂
硬度が高いために限り無く細粒化することがなく安定し
た粒度分布となる。また、クロマイト砂表面のアイアン
ビーズの除去経緯を走査電子顕微鏡で調査したところ、
残留樹脂の管理値内の4パスでほぼ除去可能であること
が確められた。また、著しく熱影響を受けたクロマイト
砂表面のアイアンビードは強力再生で除去されずに残っ
ているのがみうけられた。なお、砂再生で砂より研磨さ
れた残留樹脂と2〜20μのアイアンビード及び砂の研
磨粉は再生装置付設のダクトより極力除塵した。
Ceramic sand having a high sand hardness and a good grain shape is such that the sand surface is slightly polished and removed by sand regeneration,
The reproduction yield was 0.6%, which was a remarkably good value. In chromite sand, if the angle of the sand grains is removed to some extent, the sand hardness is high, so that the grain size does not become extremely fine and the particle size distribution becomes stable. Moreover, when the removal process of the iron beads on the chromite sand surface was investigated with a scanning electron microscope,
It was confirmed that the resin can be almost removed by 4 passes within the control value of the residual resin. It was also found that the iron beads on the surface of the chromite sand, which were significantly affected by heat, remained without being removed by intensive regeneration. It should be noted that the residual resin polished from the sand during the sand reclamation, the iron beads of 2 to 20 μm, and the abrasive powder of the sand were removed as much as possible from the duct provided with the recycling apparatus.

【0042】 本実施例で用いられたセラミック砂と
クロマイト砂は、目開き寸法が0.5mmである35mesh
の振動フルイを用いて前記一対の砂を分級した。フルイ
上に残る0.5mm以上の粗粒は再利用可能な再生セラミ
ック砂であり、フルイを通過した0.5mm未満の細粒砂
は全砂量の12%となる。
The ceramic sand and chromite sand used in this example have a mesh size of 35 mm and a mesh size of 35 mesh.
The pair of sands was classified by using the vibrating screen of. Coarse grains of 0.5 mm or more remaining on the sieve are reusable recycled ceramic sand, and fine grains of less than 0.5 mm that have passed through the sieve account for 12% of the total amount of sand.

【0043】 前記35meshの振動フルイを通過した
細粒砂を、20000ガウスの2段式ロール型磁選機に
より磁性の強弱で選別する。この時の磁選機は全砂量の
15%程度を処理する小型機種が用いられる。まず、上
段の磁選機で非磁性体と磁性体を分離して磁性体を取出
し、下段の磁選機で磁性体の中から、有効な弱磁性体で
ある熱影響が比較的少なく変質していない良好なクロマ
イト砂とアイアンビーズを除去した再利用可能なクロマ
イト砂が取出される。また、中磁性体は、砂表面層に堅
固なアイアンビードが発生して再利用困難なクロマイト
砂と、強磁性体の溶鋼が付着した砂粒、砂再生でクロマ
イト砂表面より剥離した一部のアイアンビーズ、湯玉及
び細かな鋳バリ等の鉄分であり、除去対象物として磁選
機により除去される。磁力選鉱した細粒砂の構成割合
は、非磁性体;9%、弱磁性体;74%、中磁性体と強
磁性体;17%とである。
The fine-grained sand that has passed through the 35 mesh vibrating screen is sorted according to the strength of magnetism by a 20000 Gauss two-stage roll-type magnetic separator. The magnetic separator used at this time is a small model that processes about 15% of the total sand. First, the upper magnetic separator separates the non-magnetic material from the magnetic material to take out the magnetic material, and the lower magnetic separator selects the effective magnetic material, which is a weak magnetic material and has relatively little heat effect and has not deteriorated. Good chromite sand and reusable chromite sand with iron beads removed are removed. In addition, medium magnetic materials include chromite sand that is hard to reuse due to solid iron beads generated in the sand surface layer, sand particles with molten steel of ferromagnetic material attached, and some iron particles separated from the chromite sand surface during sand regeneration. Iron components such as beads, hot water balls and fine cast burrs are removed by a magnetic separator as an object to be removed. The composition ratio of the fine-grained sand subjected to magnetic separation is non-magnetic material; 9%, weak magnetic material; 74%, medium magnetic material and ferromagnetic material; 17%.

【0044】 前記再生の結果は、新砂の歩留りはセ
ラミック砂で0.6%、クロマイト砂で19%となっ
た。システムサンドとして長期間用いた場合の歩留り
は、鋳物付着等のロスを加え、セラミック砂で約2%、
クロマイト砂で約30%程度と推定され、産業廃棄物の
大巾な低減が可能である。またセラミック砂及びクロマ
イト砂とも砂硬度が高く破砕し難い砂であり、鋳造工場
で最も問題となる解枠時の粉塵を大巾に低減するととも
に、遊離珪酸(SiO2 )含有しないセラミック砂とク
ロマイト砂により珪肺を防止することができる。
As a result of the regeneration, the yield of fresh sand was 0.6% for ceramic sand and 19% for chromite sand. The yield when used as a system sand for a long time is about 2% with ceramic sand, including loss such as casting adhesion,
Chromite sand is estimated to be about 30%, and it is possible to greatly reduce industrial waste. Both ceramic sand and chromite sand have high sand hardness and are difficult to crush, which greatly reduces dust at the time of unraveling, which is the most problematic problem in a foundry, and ceramic sand and chromite that do not contain free silicic acid (SiO 2 ). The sand can prevent silicosis.

【0045】[0045]

【発明の効果】以上、具体的に説明したように本発明の
1プロセス2サンド方式を用いる鋳鋼用自硬性鋳型は、
水溶性フェノール樹脂と硬化剤を用いた鋳鋼用水溶性フ
ェノール鋳型において、ベース砂に粒径が0.5〜1.
5mm、ヌープ硬度が900以上の高硬度の球状形状のセ
ラミック砂を用い、ポケットサンドとして前記セラミッ
ク砂と篩分け可能な粒径0.5mm未満のクロマイト砂を
適用しており、次の効果を奏することができる。 (1) 水溶性フェノール樹脂とバインダーにより鋳込
時の鋳型からのガスには、熱間割れの主原因となる硫黄
とガス欠陥の一因となる窒素の有害な成分を含まない。 (2) 鋳型の熱影響の著しい箇所の肌砂にポケットサ
ンドとしてクロマイト砂を用いることにより、クロマイ
トから還元析出する鉄分により砂粒間焼結が生じ、溶鋼
の浸透を防ぎ焼着を防止できる。 (3) ベースサンドにムライト質のセラミック砂を適
用することにより低膨張鋳型が実現し、溶鋼との反応生
成物である溶融珪酸塩が生じ難い。 (4) 粗粒のセラミック砂を用いることにより、ガス
抜が不要でシンプルな高通気度鋳型となる。
As described above in detail, the self-hardening mold for cast steel using the 1-process 2-sand method of the present invention,
In a water-soluble phenol mold for cast steel using a water-soluble phenol resin and a hardening agent, the particle size of the base sand is 0.5 to 1.
Spherical ceramic sand having a hardness of 5 mm and a Knoop hardness of 900 or more is used, and chromite sand having a particle size of less than 0.5 mm that can be sieved from the ceramic sand is used as a pocket sand. be able to. (1) Due to the water-soluble phenolic resin and the binder, the gas from the mold at the time of casting does not contain harmful components such as sulfur, which is the main cause of hot cracking, and nitrogen, which contributes to gas defects. (2) By using chromite sand as pocket sand for the skin sand of the mold where heat is significantly affected, inter-sand grain sintering occurs due to iron components reduced and precipitated from chromite, and molten steel can be prevented from penetrating and seizure can be prevented. (3) A low expansion mold is realized by applying mullite ceramic sand to the base sand, and molten silicate, which is a reaction product with molten steel, is unlikely to be produced. (4) By using coarse-grained ceramic sand, degassing is unnecessary and a simple high-permeability mold is obtained.

【0046】また、本発明の鋳物砂の再生方法は次の効
果を奏することができる。 (1) 高い硬度のセラミック砂及びクロマイト砂によ
り、強力スクラビングによる砂破砕を抑えて砂の歩留り
を高め、新砂補充量及び廃砂量の低減が可能にできると
ともに塵肺と珪肺を防止することができる。 (2) 粗粒のセラミック砂とクロマイト砂により簡単
なフルイで分級可能であり、安価な小型の磁力選鉱機で
クロマイト砂の回収が可能である。
Further, the method for reclaiming foundry sand of the present invention can exert the following effects. (1) High-hardness ceramic sand and chromite sand suppress sand crushing due to strong scrubbing to improve sand yield, reduce the amount of new sand replenishment and the amount of waste sand, and prevent pneumoconiosis and silicosis. . (2) Coarse-grained ceramic sand and chromite sand can be used for classification with a simple sieve, and chromite sand can be recovered by an inexpensive small magnetic separator.

【0047】以上の結果、本発明によれば、新しい1プ
ロセス2サンド方式により鋳鋼用に水溶性フェノール砂
プロセスを用いることができ、時代に即した大物高級鋳
鋼品の実現が可能である。
As a result of the above, according to the present invention, the water-soluble phenol sand process can be used for cast steel by the new one-process-two-sand method, and it is possible to realize a large-scale high-grade cast steel product in accordance with the times.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の実施例に当って検討した原料砂の粒度
分布図である。
FIG. 1 is a particle size distribution diagram of raw material sand studied in an example of the present invention.

【図2】焼着試験の試験片用鋳型の断面図である。FIG. 2 is a cross-sectional view of a mold for a test piece in a seizure test.

【図3】焼着試験片の斜視図である。FIG. 3 is a perspective view of a baking test piece.

【図4】本発明の実施例に係るコンプレッサー車室の鋳
鋼鋳型の断面図である。
FIG. 4 is a cross-sectional view of a cast steel mold for a compressor casing according to an embodiment of the present invention.

【図5】本発明の実施例に係る鋳物砂の再生方法を示す
1プロセス2サンド方式を示すフロー図である。
FIG. 5 is a flow chart showing a 1-process 2-sand method showing a method for reclaiming foundry sand according to an embodiment of the present invention.

【図6】従来の1プロセス1サンド方式を示すフロー図
である。
FIG. 6 is a flowchart showing a conventional 1-process 1-sand method.

【図7】従来の2プロセス2サンド方式を示すフロー図
である。
FIG. 7 is a flowchart showing a conventional 2-process 2-sand method.

【図8】従来の1プロセス2サンド方式を示すフロー図
である。
FIG. 8 is a flowchart showing a conventional 1-process 2-sand method.

【符号の説明】[Explanation of symbols]

1 鋳枠 2 定盤 3 鋳型空間部 4 押湯 4−a 押湯保温スリーブ 5 湯道 5−a 湯道スリーブ 6 外型 6−a 外型肌砂平面図 6−b 外型肌砂凸部 7 中子 8 セラミック砂 9 クロマイト砂 DESCRIPTION OF SYMBOLS 1 Casting frame 2 Surface plate 3 Mold space part 4 Hot water 4-a Hot water heat retaining sleeve 5 Runway 5-a Runway sleeve 6 Outer mold 6-a Outer skin sand plan view 6-b Outer skin sand convexity 7 Core 8 Ceramic sand 9 Chromite sand

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 1プロセス2サンド方式を用いる鋳鋼用
自硬性鋳型において、バインダーに水溶性フェノール樹
脂と硬化剤を用い、鋳物砂のベース砂には粒径が0.5
〜1.5mmで砂粒のヌープ硬度が900以上粒径系数
1.1以下の球状粒形のムライト質のセラミック砂を用
い、熱的に過酷な肌砂に用いるポケットサンドのクロマ
イト砂には前記セラミック砂とフルイ分け可能な0.5
mm未満の粒径のクロマイト砂を用いたことを特徴とする
鋳鋼用自硬性鋳型。
1. A self-hardening mold for cast steel using a 1-process 2-sand method, wherein a water-soluble phenolic resin and a hardening agent are used as a binder, and a particle diameter of 0.5 is used for the base sand of the foundry sand.
Spherical-grain type mullite ceramic sand with a Knoop hardness of 900 to 1.5 mm and a grain size of 1.1 or less is used, and the above-mentioned ceramic is used for chromite sand of pocket sand used for thermally harsh skin sand. 0.5 that can be divided into sand and sieve
A self-hardening mold for cast steel, which is characterized by using chromite sand having a particle size of less than mm.
【請求項2】 ベースサンドとして粒径が0.5〜1.
5mmのセラミック砂とポケットサンドとして粒径が0.
5mm未満のクロマイト砂を用いたアルカリフェノール回
収砂を再生するにあたり、高速回転ロータによる強力ス
クラビング方式の再生機を用いて、前記粗粒セラミック
砂とクロマイト砂の残留樹脂を除去するとともに、クロ
マイト砂の表面に析出したアイアンビーズの鉄分を取除
き、双方の砂を振動フルイにより分級し、フルイ上の粗
粒は再生したセラミック砂として再利用し、フルイ下の
細粒は、20000ガウス以上の磁選機により、アイア
ンビードを析出している中磁性体、鉄分等の強磁性体、
および非磁性体の湯道レンガ屑等を除去し、弱磁性体で
あるクロマイト砂を取出し再利用することを特徴とする
鋳物砂の再生方法。
2. A base sand having a particle size of 0.5 to 1.
The grain size is 0.5 mm as 5 mm of ceramic sand and pocket sand.
When regenerating the alkali phenol recovered sand using less than 5 mm of chromite sand, a strong scrubbing type regenerator with a high-speed rotating rotor was used to remove the residual resin of the coarse-grained ceramic sand and chromite sand and to remove the chromite sand. Iron particles of iron beads deposited on the surface are removed, both sands are classified by a vibrating screen, coarse particles on the screen are reused as recycled ceramic sand, and fine particles under the screen are magnetic separators of 20000 Gauss or more. By, medium magnetic substance that is precipitating iron beads, ferromagnetic substance such as iron,
And a method for reclaiming foundry sand, characterized by removing non-magnetic runner bricks and the like, and taking out and reusing the weak magnetic material chromite sand.
JP23299794A 1994-09-28 1994-09-28 Self-hardening mold for cast steel and method for reclaiming foundry sand Expired - Fee Related JP3268137B2 (en)

Priority Applications (1)

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JP23299794A JP3268137B2 (en) 1994-09-28 1994-09-28 Self-hardening mold for cast steel and method for reclaiming foundry sand

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP23299794A JP3268137B2 (en) 1994-09-28 1994-09-28 Self-hardening mold for cast steel and method for reclaiming foundry sand

Publications (2)

Publication Number Publication Date
JPH0890150A true JPH0890150A (en) 1996-04-09
JP3268137B2 JP3268137B2 (en) 2002-03-25

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US7673668B2 (en) * 2002-12-09 2010-03-09 Kao Corporation Spherical casting sand
KR101131363B1 (en) * 2004-05-21 2012-04-04 가오 가부시키가이샤 Resin coated sand
CN104139154A (en) * 2014-07-30 2014-11-12 吴江市液铸液压件铸造有限公司 Phenolic resin self-hardening sand and preparation method thereof
CN107297463A (en) * 2017-06-22 2017-10-27 霍山县忠福机电科技有限公司 A kind of single cylinder crankshaft casting technique
CN112517845A (en) * 2020-12-07 2021-03-19 安徽省隆兴铸造有限公司 Preparation method of sand mold for valve casting and sand mold

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7673668B2 (en) * 2002-12-09 2010-03-09 Kao Corporation Spherical casting sand
KR101131363B1 (en) * 2004-05-21 2012-04-04 가오 가부시키가이샤 Resin coated sand
CN104139154A (en) * 2014-07-30 2014-11-12 吴江市液铸液压件铸造有限公司 Phenolic resin self-hardening sand and preparation method thereof
CN107297463A (en) * 2017-06-22 2017-10-27 霍山县忠福机电科技有限公司 A kind of single cylinder crankshaft casting technique
CN112517845A (en) * 2020-12-07 2021-03-19 安徽省隆兴铸造有限公司 Preparation method of sand mold for valve casting and sand mold

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