JPS60158971A - Casting method of molten steel - Google Patents

Abstract

PURPOSE:To avert inverse V segregation and to make solidified structure finer and solidifying time shorter by pressing and lowering the top solidified shell formed by inserting heat insulating materials to the short side surfaces of a casting mold having the width and length larger than the thickness and solidifying the molten steel poured therein from the base and top surface. CONSTITUTION:A casting mold 4 fixed with heat insulating materials on the short side surfaces is inserted into a box 7 consisting of side walls and base via imposing plates 8a, 8b and thereafter a molten steel 5 is poured into the mold through a pouring pipe 10 and a vent hole 9 is sealed. A gaseous pressure of Ar, nitrogen, air, etc. is supplied to the inside of the box 7 through a gas supply pipe 14 provided to a sealing cap 11 to press-stick the top solidified shell. The similar effect is also obtainable by press-sticking the shell 15 by a pressing-down head 18 at the top end of a rod arm 17a via an advancing and retreating device 17 in place of gas pressurization.

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、溶鋼の鋳造方法に関する。[Detailed description of the invention] (Industrial application field) The present invention relates to a method for casting molten steel.

（従来技術） 一般に、溶鋼をスラブ状鋼片に製造する方法として、古
くから行なわれているところの厚肉鋳塊を分塊圧延する
造塊法と、製造コストが安く、しかも生産性が高い等の
理由から広く用いられている連続鋳造法が知られている
。(Prior art) In general, as a method for manufacturing molten steel into slab-shaped billets, the ingot forming method, in which thick-walled ingots are bloomed and rolled, has been used for a long time, and the manufacturing cost is low and productivity is high. The continuous casting method is widely used for the following reasons.

このように従来から行なわれている造塊法あるいは連続
鋳造法は、その鋳造鋼種の特性及び低コストと高生産性
の指向からそれぞれの１ノｉ造法の特徴に適した範囲に
おいて用いられている。しかし５、近年においてぬ１、
中心偏析に代表される内部欠陥の極めて少ない優れた高
級鋼材の供給が切望されており、従来の鋳造法である造
塊法及び連続鋳造法では、中心偏析等の内部欠陥の極め
て少ない鋼材を高い歩留で安く製造して供給することは
容易で彦い。そこで、例えば、特公昭５３−１９２９０
号公報の如く、鋳型の上面及び側面を保温して、鋳型底
面から上面に一方向凝固させる方法（一方向凝固法）、
特公昭４７−４８０８７号公報の如く、鋼塊押湯部に密
閉容器を挿入して該容器内を加圧する方法、及び特開昭
５０−６２１．２７号公報の如く、密閉鋳型内に溶融金
属を鋳造して後に、鋳型内壁と金属凝固殻との間隙に加
圧流体を圧入して鋳塊を圧潰する方法（圧潰法）等が行
なわれている。In this way, the conventional ingot making method or continuous casting method is used within a range that is suitable for the characteristics of each 1-no-I casting method, due to the characteristics of the cast steel type and the aim of low cost and high productivity. There is. However, 5. In recent years, 1.
There is a strong desire to supply superior high-grade steel materials with extremely few internal defects such as center segregation, and conventional casting methods such as ingot casting and continuous casting methods cannot produce steel materials with extremely few internal defects such as center segregation. It is easy to manufacture and supply at low yield. Therefore, for example,
As in the publication, a method of keeping the top and side surfaces of the mold warm and solidifying in one direction from the bottom of the mold to the top (unidirectional solidification method);
Japanese Patent Publication No. 47-48087 discloses a method in which a closed container is inserted into a steel ingot feeder and the inside of the container is pressurized, and JP-A-50-621.27 discloses a method in which molten metal is placed in a closed mold. After casting the ingot, pressurized fluid is injected into the gap between the inner wall of the mold and the solidified metal shell to crush the ingot (the crushing method).

しかし、これ等従来方法は、中心偏析の極めて優れた鋼
材の鋳造方法としては、以下に述べる理由から充分とは
言い難い。However, these conventional methods cannot be said to be sufficient as methods for casting steel materials with extremely excellent center segregation for the reasons described below.

まず、一方向凝固法においては、上面及び側面を充分に
保温することから、多量の保温剤を使用するために、経
済性に欠けると共に、該鋳片上層部の濃縮偏析層を除去
するため歩留が大巾に低下する等の欠点を有している。First, in the unidirectional solidification method, since the top and side surfaces are sufficiently insulated, it is not economical because a large amount of heat insulating agent is used, and it is necessary to take steps to remove the concentrated and segregated layer in the upper layer of the slab. It has drawbacks such as a significant drop in retention.

また、押湯部に密閉容器を挿入して該容器内を加圧する
方法は、鋳塊の押湯部に密閉容器の一端を挿入溶着させ
るだめに、該密閉容器を毎回補修するか、もしくは、毎
回取替る必要があり、その費用が多大となり経済性に欠
ける。In addition, the method of inserting a sealed container into the feeder part and pressurizing the inside of the container requires repairing the sealed container each time in order to insert and weld one end of the sealed container into the feeder part of the ingot, or, It is necessary to replace it every time, and the cost is large, which makes it uneconomical.

また、鋳塊に押湯部を設けることから該押湯部を切りす
てるために、歩留が大巾に低下すると共に、上広鋳塊の
鋳造の際には、前記の密閉容器が大型化し実用的でない
等の欠点を有している。In addition, since a feeder section is provided in the ingot, the yield is significantly reduced because the feeder section is cut off, and when casting a top-wide ingot, the above-mentioned closed container is large. However, it has drawbacks such as being unusable and impractical.

一方、圧潰法は、鋳型自体を密閉構造とするために、そ
の製作と修復に多大の手間を要することから、コストが
高く、しかも鋳型の熱変形、あるいは溶損等によシ該鋳
型の取替が多発し、しかも鋳塊の加圧を注入直後から行
ない、且つ全周囲から加圧するだめに、溶鋼中のガスが
封じこめられて鋳塊内部に気泡性欠陥が発生し、鋳塊形
状によっては短側面近傍相当内部に偏析線を伴う等の欠
点を有している。On the other hand, the crushing method requires a lot of time and effort to manufacture and repair the mold itself because it has a sealed structure, which is expensive, and also prevents the mold from being removed due to thermal deformation or melting damage. Frequent replacements occur, and because the ingot is pressurized immediately after pouring and from all around, the gas in the molten steel becomes trapped and bubble defects occur inside the ingot, causing damage due to the shape of the ingot. has disadvantages such as segregation lines in the vicinity of the short side.

（発明の目的） 本発明は、前述した如き従来法の欠点である保温材の使
用量が少なく、鋳片の歩留も極めて高く、しかも、鋳塊
の気泡性欠陥の発生がなく、実用性の高い優れた溶鋼の
鋳造法であって、その特徴とするところは、少なくとも
鋳型知側内面を断熱もしくは発熱保温して鋳込溶鋼を底
部から凝固せしめつつ、該鋳込溶鋼を上面からも凝固せ
しめて、上面凝固殻を抑圧下降することにあり極めて効
果的に高品質の鋳塊を得ることのできる溶鋼の加圧鋳造
法である。(Objectives of the Invention) The present invention uses a small amount of heat insulating material, which is a disadvantage of the conventional method as described above, has an extremely high yield of ingots, and does not cause bubble defects in the ingots, making it practical. This is an excellent casting method for molten steel with high performance, and its characteristics are that at least the inner surface of the inner side of the mold is insulated or heat-retained to solidify the molten steel from the bottom, while also solidifying the molten steel from the top. At the very least, it is a pressure casting method of molten steel that can extremely effectively obtain high quality ingots by suppressing and descending the upper solidified shell.

（発明の構成・作用） 以下、本発明の方法について詳細に述べる。本発明は、
溶鋼を鋳造する際に、鋳塊の内部欠陥である凝固収縮孔
と逆■、点状偏析等を解消するために、発明者等の検討
と各種実験に基づいて得られだ知見により成し得たもの
である。(Structure and operation of the invention) The method of the present invention will be described in detail below. The present invention
In order to eliminate solidification shrinkage pores, reverse ■, point segregation, etc., which are internal defects in the ingot, when casting molten steel, the inventors have developed a method based on their findings based on their studies and various experiments. It is something that

すなわち、従来の加圧鋳造が鋳込直後から鋳塊表面を加
圧するだめに、鋳込溶鋼内部に封じ込められたガス体が
気泡を形成し、また、凝固殻のいまだ薄い状況下での加
圧は、この形成段階にある薄い凝固殻部を植傷し鋳塊の
表面及び内部欠陥の生成を招く等の障害がある。In other words, because conventional pressure casting pressurizes the ingot surface immediately after casting, gas trapped inside the cast molten steel forms bubbles, and pressure is applied when the solidified shell is still thin. This causes problems such as implantation of the thin solidified shell at this stage of formation, leading to the formation of surface and internal defects in the ingot.

一方、従来の加圧鋳造においては、鋳塊の形状によって
は短側面近傍相当の鋳塊内部に短側面の凝固の進行に伴
う短側面凝固殻と底面及び上面凝固殻との凝固殻の合体
形成により、収縮孔及び点状偏析等が極めて容易に生成
されることを知見し得た。これは、鋳塊の凝固が短側面
と下面部及び上面部から行なわれるために、各凝固方向
面に形成された凝固殻が箱型合成体を形成し、凝固末期
に移行する程前記形成合成体が強固なものになるため、
該鋳塊の上面及び側面を加圧しても内部の凝固収縮によ
多形成された収縮孔を抑圧にて圧着することができない
。また、この形成合成体を押圧蓋するには、極めて高い
加圧力を用いて強制押圧することによりある程度性ない
得るが、これは既に充分に形成された合成体を強制押圧
するだめに加圧装置に多大の費用を要すると共に凝固殻
にむりな変形をしいることから該凝固殻に割れに起因し
た表面及び内部欠陥の生成を招き易い。On the other hand, in conventional pressure casting, depending on the shape of the ingot, a solidified shell of the short side solidified shell and the bottom and top solidified shells is formed inside the ingot corresponding to the vicinity of the short side as the short side solidifies. It was found that shrinkage pores, point segregation, etc. are extremely easily generated. This is because solidification of the ingot is performed from the short side, lower surface, and upper surface, so the solidified shells formed on each surface in the solidification direction form a box-shaped composite body, and as it moves to the final stage of solidification, the solidified shells form a box-shaped composite body. To make your body stronger,
Even if the top and side surfaces of the ingot are pressurized, the shrinkage holes formed due to internal solidification shrinkage cannot be compressed and bonded. In addition, in order to press the lid on this formed composite, it may be difficult to forcibly press using an extremely high pressure, but this is because the pressurizing device is not suitable for forcibly pressing a composite that has already been sufficiently formed. This method requires a large amount of cost, and since the solidified shell is subjected to forced deformation, surface and internal defects due to cracks are likely to occur in the solidified shell.

さらにまた、前述した如き短側面中心和尚内部の凝固収
縮孔及び点状偏析の形成と凝固殻の箱型合成体は、鋳片
のサイズが小さい程顕著となり鋳造サイズが制約される
等をも知見し得た。Furthermore, we also found that the formation of solidification shrinkage pores and point segregation inside the center of the short side and the box-shaped composite of the solidified shell, as described above, become more pronounced as the size of the slab becomes smaller, which limits the casting size. I was able to do it.

本発明は、前述した如く、単に、加圧鋳造しても鋳片サ
イズあるいは成分、温度等の鋳造条件によって、収縮孔
、偏析等を伴うその主因が凝固殻の合成体にあることを
察知し、この合成体の形成を抑止して、上面及び下面か
らの凝固の促進と短側面の遅固によって、内部溶伽の凝
固収縮に追従して上面凝固殻を充分に、且つ、極めて容
易に抑圧下降することにある。而して、本発明による方
法は、溶鋼を鋳造する際に、鋳塊の少なくとも短側面を
断熱、もしくは発熱保温することによって、該鋳塊の側
面からの凝固を適宜抑止すると共に、１１７塊の下面を
ｔ４＋型を構成する定盤の吸熱と該定盤の放熱によ・つ
て凝固せしめつつ、上面からも該鋳塊かもの放熱にて冷
却凝固し、次いで、上面凝固殻を内部溶鋼の凝固収縮に
見合って、例えば空気、窒素、もしくはアルゴン等の気
体流体にて加圧して下降せしめるか、あるいは油圧を用
いた進退装置、もしくはウェイト等を用いて機械的に押
圧して下降圧着せしめる。As mentioned above, the present invention has discovered that even if pressure casting is performed, the main cause of shrinkage pores, segregation, etc. is due to the composite solidified shell, depending on the casting conditions such as slab size, composition, and temperature. By suppressing the formation of this composite, promoting solidification from the upper and lower surfaces, and slow solidification of the short sides, the solidified shell on the upper surface can be sufficiently and extremely easily suppressed by following the solidification contraction of the internal melt. It lies in descending. Therefore, when casting molten steel, the method according to the present invention appropriately suppresses solidification from the sides of the ingot by insulating or heat-insulating at least the short side of the ingot, and also prevents solidification of the 117 ingots. While the lower surface is solidified by the heat absorption of the surface plate forming the T4+ type and the heat radiation of the surface plate, the upper surface is also cooled and solidified by the heat radiation of the ingot, and then the upper surface solidified shell is solidified by the solidification of the internal molten steel. In proportion to the shrinkage, it is pressurized with a gaseous fluid such as air, nitrogen, or argon to lower it, or it is pressed down mechanically using a hydraulic advance/retreat device or a weight or the like to press it down.

とのｆ４Ｑ塊知側面の断熱、もしくは発熱保温は、鋳型
の短側面と鋳塊との間に通常の造塊法で押湯枠として用
いている断熱性、もしくは発熱性と断熱性を有する適宜
耐火性物質（ＳｉＯ□、Ａ１２０３１ＭＡｌ２０３ｌな
どの）や酸化発熱剤（ｆｉ、ｌ、酸化鉄など）からなる
も、混合成形品を適宜厚み介挿すること１てよって側面
からの凝固を抑制せしめる。なお、前記の介挿物は、第
１表に示すような組成および物性の市販品を用いてもよ
い。The insulation of the f4Q ingot side, or the heat-generating heat retention, is the insulation between the short side of the mold and the ingot, which is used as a riser frame in the normal ingot-making method, or the appropriate heat-insulating material that has heat-generating and heat-insulating properties. By inserting a mixed molded product made of a refractory material (SiO□, A12031MAl203L, etc.) or an oxidative exothermic agent (FI, L, iron oxide, etc.) to an appropriate thickness, solidification from the side surface can be suppressed. As the above-mentioned insert, a commercially available product having the composition and physical properties shown in Table 1 may be used.

第１表 ※アルカリ上類元素酸化物 また、発明者等の実験では第１表に示す組成で厚み５０
ｍｍのものを介挿した場合に短ｊｔｌｌ１面の凝固速度
は底面の凝固速度の１／３から１／４に減少烙れυｊ塊
の凝固過程における、上面凝固殻の下降が容易に行ない
えた。Table 1 *Alkali upper element oxides In addition, in the inventors' experiments, the composition shown in Table 1 had a thickness of 50 mm.
When a 1 mm thick piece was inserted, the solidification rate on one surface of the short jtll was reduced to 1/3 to 1/4 of the solidification rate on the bottom surface, and the upper solidified shell could be easily lowered during the solidification process of the scorched υj mass.

さらにまた、溶鋼の上面凝固殻の下降は、上面の凝固が
開始する時点である注入路りから３０秒以上経過後より
凝固完了まで、該鋳塊の上面を押圧することが好捷しく
、注入路りからの抑圧開始が３０秒未満では、特に加圧
の場合に溶鋼に包含されたガス気泡の逸散が妨けら打る
。Furthermore, the lowering of the upper surface solidified shell of molten steel is preferably carried out by pressing the upper surface of the ingot from 30 seconds or more after the injection path, which is the point at which solidification of the upper surface starts, until solidification is completed. If the suppression from the road starts for less than 30 seconds, the escape of gas bubbles contained in the molten steel is hindered, especially in the case of pressurization.

！た、該凝固殻の形成が初期においては、薄いため容易
に損傷される。さらに、この抑圧開始時間は、その鋳造
した溶鋼の成分、温度及び鋳型等の冷却条件等によって
異なるもので作業経験よりめられた時間は、長くて２分
後である。! In addition, when the solidified shell is initially formed, it is thin and easily damaged. Furthermore, this suppression start time varies depending on the composition of the cast molten steel, the temperature, the cooling conditions of the mold, etc., and the time estimated from work experience is two minutes at most.

本発明は、鋳塊の短側面を断熱保温して遅固するために
、２．０に９／Ｃｒｌから６．ＯＫｙ／ｄ（ゲージ圧）
の低い押圧力でもって上面凝固殻を押圧蓋できると共に
、鋳塊の短側面を断熱保温することにより、上部の凝固
を上面凝固殻の下降とは独立して広範囲にコントロール
し得るので、凝固速度が小さい場合に問題となる逆Ｖ偏
析を回避出来るうえ、上部の冷却強化が可能となる結果
、凝固組織の微細化や凝固時間の短縮にできる。In the present invention, in order to insulate the short side of the ingot and slow harden it, the ingot is changed from 2.0 to 9/Crl to 6. OKy/d (gauge pressure)
By pressing the top solidified shell with a low pressing force and insulating the short sides of the ingot, solidification at the top can be controlled over a wide range independently of the descent of the top solidified shell, thereby increasing the solidification rate. It is possible to avoid inverted V segregation, which is a problem when the amount is small, and it is also possible to strengthen the cooling of the upper part, so that the solidification structure can be made finer and the solidification time can be shortened.

なお、前記の押圧力が２．ＯＫ９／Ｃ１ｄ未満では、凝
固の中期以降における上面凝固殻の押圧蓋が不足するた
めに鋳塊内部に収縮孔が発生する。また、６、　ＯＫｙ
　／ｃｄ１以上の過大押圧力は鋳塊凝固殻の損傷を招、
くと共に、抑圧装置が太きくしかも高価となる。Note that the above pressing force is 2. If it is less than OK9/C1d, shrinkage pores are generated inside the ingot due to insufficient pressing cover of the upper solidified shell after the middle stage of solidification. Also, 6, OKy
Excessive pressing force of /cd1 or more will cause damage to the solidified ingot shell,
At the same time, the suppression device becomes bulky and expensive.

また、本発明の上面凝固殻の抑圧装置としては、第２図
の（ａ）（後述する）のように鋳型を内包する加圧容器
を用いても良く、また、第２図の（ｂ）（後述する）の
ように鋳型自体を加圧容器の一部として使用する方法も
適用できる。さらに、ガス加圧の代りに、第３図（後述
する）に示すように機械的圧下刃を鋳塊の上部に加えて
もガス加圧と同様な効果が得られた。Furthermore, as the suppression device for the upper solidified shell of the present invention, a pressurized container containing a mold as shown in FIG. 2(a) (described later) may be used, or a pressurized container containing a mold may be used as shown in FIG. 2(b). A method in which the mold itself is used as a part of the pressurized container as in (described later) can also be applied. Furthermore, instead of gas pressurization, a mechanical reduction blade was added to the top of the ingot as shown in FIG. 3 (described later), and the same effect as gas pressurization was obtained.

（実施例） 次に、本発明の方法による一実施例を図面に基づいて詳
細に述べる。(Example) Next, an example of the method of the present invention will be described in detail based on the drawings.

第１図は、本発明の方法による一実施例を示すものでま
ず、第１図の（ａｌにおいて、短側面１ａと１ｂ及び長
側面２ａと２ｂ（図示せず）と底面３とから箱型を構成
した鋳型４の少なくとも短側面１ａと１ｂに、例えば造
塊で押湯枠として通常使用する断熱、もしくは発熱保温
性の例えば２０〜６０關の板状の断熱材６を釘、あるい
はｄ３り金等で短鎖内面に固設する。この鋳型４は、側
壁及び底面からなる箱７の内部に載置台８ａ、８ｂを介
して内挿されて後Ｋ、例えば円筒状のガス抜き孔９と該
ガス抜き孔９の内部に注入管１０を固設した密閉蓋１１
を前記箱７の上面に例えばボルトナツトの如き、手段で
固設することによって全周囲を包囲する。FIG. 1 shows an embodiment according to the method of the present invention. First, in FIG. On at least the short sides 1a and 1b of the mold 4, for example, a heat insulating material 6 normally used as a feeder frame in ingot making, or a plate-shaped heat insulating material 6 having heat retention properties of 20 to 60 mm, is attached with nails or d3. The mold 4 is fixed on the inner surface of the short chain with gold or the like.The mold 4 is inserted into the inside of the box 7 consisting of the side walls and the bottom via the mounting tables 8a and 8b, and then the mold 4 is inserted into the box 7, which is made up of side walls and a bottom surface, and is then inserted into the rear K, for example, with a cylindrical gas vent hole 9. an airtight lid 11 with an injection tube 10 fixed inside the gas vent hole 9;
is fixed to the upper surface of the box 7 using means such as bolts and nuts, thereby surrounding the entire periphery.

このように、全体を包囲した鋳型４に取鍋（図示せず）
から溶鋼５を前記の注入管１０を介して注入する。溶鋼
５を注入して後に充分に該溶鋼５０発生ガスを逸散して
後に、ガス抜き孔９の上部を上器１３にて密閉し、次い
で、前記の密閉蓋Ｖ１に穿設した気体供給管１４に連設
された例えばコンプレッサー（図示せず）の如き加圧源
に連接した気体供給管〕４を介して、Ａｒ“′、窒素、
空気等の気体圧を前記箱７の内部に供給する。この気体
圧の供給により鋳型４の溶鋼５が凝固収縮する際に、上
面凝固殻が押圧蓋される。また、第２図の（ｂｌは、鋳
型４に直接前記第１図の（ａｌで述べた密閉蓋１１を固
設すると共に、断熱材６を鋼塊厚み方向で比較的上部に
介挿し、しかも上部程厚くなるものを用いた他は第１図
の（ａｌに同じであり、はぼ（ａｌと同様の効果が得ら
れた。In this way, a ladle (not shown) is placed in the mold 4 that surrounds the whole.
Molten steel 5 is injected through the injection pipe 10 described above. After injecting the molten steel 5 and sufficiently dissipating the gas generated by the molten steel 50, the upper part of the gas vent hole 9 is sealed with the upper container 13, and then the gas supply pipe bored in the sealing lid V1 is Ar'', nitrogen,
Gas pressure such as air is supplied to the inside of the box 7. When the molten steel 5 in the mold 4 solidifies and shrinks by supplying this gas pressure, the upper solidified shell is pressed and covered. In addition, (bl in FIG. 2) fixes the sealing lid 11 described in (al) in FIG. It was the same as (al) in Fig. 1 except that a material that became thicker toward the top was used, and the same effect as that of (al) was obtained.

さらにまた、第２図は、気体加圧に替えて鋳型４内の溶
鋼５の凝固収縮に伴なって、上面凝固殻１５を圧下架台
１６に固設した進退装置１７を介してロッドアーム１７
ａの先端に係合した圧下ヘッド１８により圧着させるも
ので、第１図の（ａ）及び（１））と同等の効果が得ら
れる。Furthermore, in FIG. 2, instead of gas pressurization, the upper surface solidified shell 15 is moved to the rod arm 17 via an advancing/retracting device 17 fixed to a lowering frame 16 as the molten steel 5 in the mold 4 solidifies and shrinks.
The pressure is applied by the rolling head 18 engaged with the tip of the tip 1, and the same effect as in (a) and (1) in FIG. 1 can be obtained.

（発明の効果） 次に、本発明の方法において第１図の（ａｉに示す鋳型
全体を包囲して加圧したａｉ造を第２表に従来法と比較
して示す。第２表において、鋳塊の厚みが３００〜５０
０關で、しかも、Ｌ／ｌ≧２０のものを鋳塊の長手方向
面Ｃ広面）を水平になるように鋳型を設置して鋳造し、
且つ、断熱材として５０關厚のものを介挿すると共に、
２．５　Ｋ９　／　ｃｎｒ　（ゲージ圧）以上の気体圧
を用いて注入終了から３０秒以上経過後に全体を加圧し
た本法は、従来加圧法では短側面に断熱材を介挿しない
（ロ）か、１だは鋳塊の長手方向を直立した（ハ）場合
は収縮孔の発生とかなりの濃厚偏析が形成されるのに対
し、収縮孔及び偏析がなく優れている。寸だ、一方向凝
固（イ）との比較においても収縮孔の発生がない点では
同じであるが本法が上層部の偏析がないこと及び微細な
凝固組織が得られる。(Effects of the Invention) Next, Table 2 shows a comparison of the method of the present invention in which the entire mold (ai) shown in FIG. 1 is surrounded and pressurized. The thickness of the ingot is 300~50
0 ratio and L/l≧20 is cast by installing a mold so that the longitudinal surface (C wide surface) of the ingot is horizontal,
In addition to inserting a 50mm thick insulation material,
2.5 This method uses a gas pressure of K9/cnr (gauge pressure) or higher to pressurize the entire body after 30 seconds or more have elapsed from the end of injection, and conventional pressurization methods do not require insulation on the short side (b). In contrast to the case (c) in which the longitudinal direction of the ingot is upright, shrinkage pores and considerable dense segregation are formed, whereas the ingot is superior in that there are no shrinkage pores and segregation. In comparison with unidirectional solidification (A), there is no shrinkage pores, but this method does not cause segregation in the upper layer and provides a fine solidified structure.

また、第３図に本法（ハ）と一方向凝固（イ）との各鋳
塊の厚み方向毎の偏析評価を示すが本法が極めて優れて
いる。Furthermore, Fig. 3 shows the segregation evaluation in each thickness direction of each ingot using the present method (c) and unidirectional solidification (a), and the present method is extremely superior.

以上述べたように本発明による方法を用いることによっ
て、凝固収縮孔がなく、しかも成分偏析の極めて少ない
優れた高品質の鋳塊を得ることができると共に、望むと
ころの鋳塊サイズをも容易に製造できる。また、鋳塊の
上面凝固殻の押圧が簡単で、しかも、低抑圧力で充分達
成できるために設備及び補修費も少なく、装置の信頼度
が高いことから得られる品質も安定した優ねた鋳造法で
ある。As described above, by using the method of the present invention, it is possible to obtain an excellent, high-quality ingot that has no solidification shrinkage pores and has extremely low component segregation, and it is also possible to easily obtain the desired ingot size. Can be manufactured. In addition, it is easy to press the solidified shell on the top surface of the ingot, and it can be achieved with a low suppressing force, so equipment and repair costs are low, and the reliability of the equipment is high, resulting in stable quality and excellent casting. It is the law.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図の（ａｌは、本発明の方法による一実施例を示し
、鋳型全体を内包にて加圧する場合を示し、卯、１図の
（ｂｌは、鋳型を加圧容器とししかも断熱材を鋼塊厚み
方向で比較的上部に介挿した場合を示し、第３図は本法
と従来法の偏析評価の比較を示す。 ｌａ、ｉｂ・・・短側面 ３・・・底　面 ４・・・鋳　型 ５・溶　鋼 ６・・断熱材 ７・箱 ９　ガス抜き孔 １０・・　注　入　省 Ｊｌ・・・密　閉　蓋 １３・・上　蓋 １４・気体供給管 １５・・上面凝固殻 １６・・・圧下架台 １７・・・進退装置 １８・・・圧下ヘッド 第　１　図 （α） 第２図 第３図 手続補正書 昭和５８年７り月／ｉ／−日 特許庁長官　若　杉　和　夫　殿 １、事件の表示 昭和５８年特許願第１８９９５０号 ２゜発明の名称 溶鋼の鋳造法 ６、補正をする者 事件との関係　特許出願人 住所　東京都千代田区大手町２丁目６番３号名　称　（
６６５）新日本製鐵株式会社代表者　武　１）　豊 ４、代　理　人　〒１０５　置　（５０３）　４８７７
住　所　東京都港区西新橋１−１２−１第１森ビル８１
号６、補正の対象　明１間書の発明の詳細な説明の欄Ｚ
内　容 （１）　明細書第６頁１８行から第４頁４行目の「しか
も、鋳型の熱変形、あるいは、゛偏析線を伴う等の欠点
を有している。」とあるを削除し以下の文を挿入する。 「しかも、鋳型の熱変形による鋳型の取替が多発し、ま
た、上面の凝固殻が注入直後から急速に成長するだめに
、溶鋼中のガスが封じこめられて、鋳塊内部に気泡性欠
陥が元肥する等の欠点を有している。」 （２）同第４頁１９行目の 「凝固収縮孔と逆Ｖ、点状偏析等を」とあるを 「凝固収縮孔と逆Ｖ偏析線、点状偏析等を」に補正する
。 （３）同第５頁２行目から同ろ行において「すなわち、
従来の加圧鋳造が鋳込直後から鋳塊表面を加圧するため
に、鋳込溶鋼内部に封じ込め」とあるを削除し以下の文
を挿入する。 １すなわち、従来の加圧鋳造は、鋳込直後から上面の凝
固殻が急速に成長するために、鋳込溶鋼内部に封じ込め
」 （４）同第７頁の１３行から１４行にかけて、［酸化発
熱剤（Ａｌ、酸化鉄など）からなるも、混合成形品を」
とあるを１−酸化発熱剤（Ａｌ、酸化鉄など）からなる
ものの、混合成形品を」に補ＩＦする。 （５）同第８頁の下から６行から下から５行にかけて 「注入路りからの抑圧開始が６０秒未満では、特に加圧
の場合に溶鋼に包含されたガス気泡の逸散が妨げられる
。」とあるを削除し以下の文を挿入する。 ［注入路りからの押圧開始壕での時間が６０秒未満では
、加圧に伴゛りて上面の凝固が急速に進みガス気泡の逸
散が妨げられる。Ｊ（６）　同第９頁の１１行目から１
２行目にかけて、［凝固組織の微細化や凝固時間の短縮
にできる。」とあるを 「凝固組織の微細化や凝固時間の短縮ができる。」に補
正する。 （７）同第１１頁の７行目から８行目にかけて、「ガス
抜き孔９の上部を上蓋１６にて密閉し、」とあるを 「ガス抜き孔９の上部に上蓋１３を載置しボルトナツト
（図示せず）等の手段で一体に固設して、該ガス抜き孔
９の上部を密閉し」に補正する。 （８）同第１４頁の第２表を別表の如くに補正す。 手続補正書（方式） 昭和６０年３月ｑ−日 特許庁長官　殿 １事件の表示 昭和５８年特許願第１８９９５０号 ２発明の名称 溶鋼の鋳造法 ３、補正をする者 事件との関係　特許出願人 住　所　東京都千代田区大手町２丁目６番３号名称　（
６６５）新日本製鐵株式会社 代表者　武　１）　豊 ４代　理　人　＝ｉ’１ｏ５電（５０３）４８７７７、
補正の内容 （１）明細警部１５頁下から３行目において、１−・・
・・・し、」と「第３図は・・・・・」との間に次の文
章を挿入する。In Figure 1, (al) shows an example of the method of the present invention, in which the entire mold is pressurized by enclosing it; The case is shown in which the steel ingot is inserted relatively upper in the thickness direction, and Figure 3 shows a comparison of segregation evaluation between this method and the conventional method. la, ib...Short side 3...Bottom side 4...・Mold 5・Mold steel 6・・Insulation material 7・Box 9 Gas vent hole 10・・Injection saving Jl・Sealing lid 13・・Top lid 14・Gas supply pipe 15・・Top solidified shell 16・・・・Reduction mount 17 ・Advancing/retracting device 18 ・・Reduction head Fig. 1 (α) Fig. 2 Fig. 3 Procedural amendment document July 1982/i/- Mr. Kazuo Wakasugi, Commissioner of the Patent Office 1. Indication of the case 1989 Patent Application No. 189950 2. Name of the invention Molten steel casting method 6. Person making the amendment Relationship to the case Patent applicant address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name Title (
665) Nippon Steel Corporation Representative Takeshi 1) Yutaka 4, Agent Address: 105 (503) 4877
Address Daiichi Mori Building 81, 1-12-1 Nishi-Shinbashi, Minato-ku, Tokyo
Item 6, Subject of amendment Column Z for detailed explanation of the invention in the memorandum 1
Contents (1) From page 6, line 18 to page 4, line 4 of the specification, the statement ``Moreover, it has drawbacks such as thermal deformation of the mold or ``segregation lines'' has been deleted. Insert the following sentence. "Moreover, molds have to be replaced frequently due to thermal deformation of the mold, and because the solidified shell on the top surface grows rapidly immediately after pouring, the gas in the molten steel is trapped, causing bubbles to form inside the ingot. (2) On page 4, line 19, the phrase ``solidification shrinkage pores, inverted V, point segregation, etc.'' has disadvantages such as ``solidification shrinkage pores and inverted V segregation lines, etc.'' , point segregation, etc. are corrected. (3) On page 5, line 2 to the same line, ``In other words,
In conventional pressurized casting, the ingot surface is pressurized immediately after pouring, so the "contained inside the cast molten steel" is deleted and the following sentence is inserted. 1. In other words, in conventional pressure casting, the solidified shell on the top surface grows rapidly immediately after casting, so it is confined inside the cast molten steel.'' (4) From lines 13 to 14 on page 7, Mixed molded products made of exothermic agents (Al, iron oxide, etc.)
1-For mixed molded products made of oxidized exothermic agents (Al, iron oxide, etc.), amended to IF. (5) From the 6th line from the bottom to the 5th line from the bottom of page 8, it says, ``If the start of suppression from the injection path is less than 60 seconds, gas bubbles contained in the molten steel will be hindered from escaping, especially when pressurized. ” and insert the following sentence. [If the time in the trench from the injection path to start pressing is less than 60 seconds, solidification of the upper surface rapidly progresses as pressure is applied, preventing gas bubbles from escaping. J(6) 1 from line 11 on page 9
Towards the second line, [the solidification structure can be made finer and the solidification time can be shortened. " is corrected to "It is possible to make the coagulation structure finer and shorten the coagulation time." (7) From line 7 to line 8 on page 11, the phrase "the upper part of the gas vent hole 9 is sealed with the upper lid 16" has been replaced with "the upper lid 13 is placed on the upper part of the gas vent hole 9". They are fixed together with bolts and nuts (not shown) or the like, and the upper part of the gas vent hole 9 is sealed and corrected. (8) Table 2 on page 14 of the same page shall be amended as shown in the attached table. Procedural amendment (method) March q, 1985 Commissioner of the Japan Patent Office 1 Display of the case 1989 Patent Application No. 189950 2 Name of the invention Method for casting molten steel 3 Relationship with the person making the amendment Patent application Address 2-6-3 Otemachi, Chiyoda-ku, Tokyo Name (
665) Nippon Steel Corporation Representative Takeshi 1) Yutaka 4th generation Masato = i'1o5 Den (503) 48777,
Contents of the amendment (1) In the third line from the bottom of page 15 of the detail inspector, 1-...
Insert the following sentence between "..." and "Figure 3...".

Claims (1)

【特許請求の範囲】[Claims] 幅及び長さが厚みよりも大きい鋳型を用いた溶鋼の鋳造
において、該鋳型の短側面に断熱材を介挿して、鋳込溶
鋼を底面より凝固せしめつつ、上面からも凝固させて上
面凝固殻を形成させ、次いで、鋳込溶鋼の内部収縮に追
従して該上面凝固殻を抑圧下降させることを特徴とする
溶鋼の鋳造法。When casting molten steel using a mold whose width and length are larger than its thickness, a heat insulating material is inserted on the short side of the mold to solidify the molten steel from the bottom and also from the top, forming a top solidified shell. 1. A method for casting molten steel, which comprises forming a molten steel shell, and then suppressing and lowering the upper solidified shell in accordance with the internal contraction of the molten steel.