JPS60244459A - Production of clad steel ingot - Google Patents

Abstract

PURPOSE:To cast a clad steel ingot having excellent adhesiveness without foreign matter at the boundary between a base metal and cladding metal in the stage of producing the clad steel ingot by disposing the cladding metal to the inside wall of a casting mold and heating the same to the extent of preventing the surface from melting then pouring the melt of the base metal into the mold. CONSTITUTION:The cladding metal 4 such as a stainless steel is installed to the inside wall of the casting mold 2 and a heater 5 is lowered in proximity to the surface 41 of the metal 4 to be joined to the base metal. The surface of the metal 4 is heated by the combustion flame, etc. of the heater to about 400- 1,200 deg.C at which said metal does not melt. A carburization- or oxidation-preventive agent is preliminarily coated on the surface of the metal 4 to prevent said surface from being oxidized of carburized by the heating flame. The heater 5 is pulled up when the metal 4 is heated to the intended temp. The molten steel 6 which is the base metal is cast by bottom pouring through a runner 3 right thereafter. The clad steel ingot having excellent adhesiveness is thus produced without presence of the foreign matter such as slag at the boundary between the base metal 6 and the cladding metal 4.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明性クラッド鋼塊の製造方法に関する０ 〔従来の技術及びその問題点〕 り２ツド鋼板の一製造方式として鋳込圧延法が知られて
おル、一般にこの方式では合せ材（芯材）たるスラブ又
は厚板を母材溶鋼で鋳包んで鋳塊を作シ、これを分塊圧
延→板圧延することによシフ２ツド鋼板が製造されるＯ しかし力からこの方式では、母材溶鋼の鋳込時に母材と
合せ材との界面に溶鋼中のスラグ系介在物や浮遊スカム
が巻き込まれ、この結果その界面の清浄度が害され、製
品の品質を低下させるという問題がある。このような問
題に対し、従来プラスチック等の有機材料やＺｎ等の低
沸点金属のコーティングを合せ材表面に予め施すことに
よ）、鋳込中における合せ材／母材の界面にガス被膜を
形成させるようにし、これによって合せ材表面に異物が
直′Ｉ＆接触することを防止したル、或は合せ材周辺に
耐大物等からなる可動式の隔壁を設け、合せ材と母材溶
鋼との直接接触を機械的に防止したシすることによル、
スカム等の巻き込み防止を図るようにした方法が提案さ
れているが、母材と合せ材とはいずれ直接接触するもの
であるため、このような方法唸一時的な巻込防止対策に
過ぎず、スラブ等の巻き込みの安定した防止対策として
は不十分なものである。[Detailed Description of the Invention] [Industrial Field of Application] 0 Regarding the Manufacturing Method of the Inventive Clad Steel Ingot [Prior Art and its Problems] Cast rolling method is known as a manufacturing method of clad steel plate. In general, in this method, a slab or thick plate serving as the core material is cast in base material molten steel to produce an ingot, which is then subjected to blooming and then plate rolling to produce a shifted steel plate. However, in this method, slag-based inclusions and floating scum in the molten steel are drawn into the interface between the base metal and the laminate when the base metal molten steel is poured, which impairs the cleanliness of the interface. There is a problem that the quality of the product is degraded. To solve this problem, conventional techniques have been used to form a gas film at the interface between the laminate and the base material during casting by applying a coating of an organic material such as plastic or a low-boiling metal such as Zn to the surface of the laminate in advance. This prevents foreign matter from coming into direct contact with the surface of the cladding material, or a movable partition wall made of heavy-duty material is installed around the cladding material to prevent direct contact between the cladding material and the base metal molten steel. By mechanically preventing contact,
Methods have been proposed to prevent the entrainment of scum, etc., but since the base material and the laminate will eventually come into direct contact, such methods are only temporary measures to prevent entrainment. This is insufficient as a stable measure to prevent entrainment of slabs, etc.

また以上のような鋳込圧延法で拡、分塊圧延等の圧延過
程で合せ材と母材との溶着接合性の確保が図られるが、
一般にその溶着接合性を十分に確保するためには、合せ
材を母材溶鋼で完全に鋳包む必要があシ、そのために−
貫歩留が悪く製造コストが高いという難点がある。In addition, the welding and bonding properties between the laminate and the base material are ensured during the rolling process such as expansion and blooming using the above-mentioned casting rolling method, but
Generally, in order to ensure sufficient weld bondability, it is necessary to completely cast the cladding material with the base metal molten steel.
It has the disadvantages of poor yield and high manufacturing cost.

発明明社このような従来の問題点に鑑み創案されたもの
で、母材と合せ材の界面への異物巻き込みを防止し、し
かも両材料の密着性を適切に確保することができる方法
を提供せんとするものである。Invention Meisha was devised in view of these conventional problems, and provides a method that can prevent foreign matter from getting caught in the interface between the base material and the laminate, while also ensuring appropriate adhesion between the two materials. This is what I am trying to do.

〔発明の構成〕[Structure of the invention]

このため本発明は、加熱装置によシ、鋳型内に位置せし
められた合せ材−〇母材と接合すべき面を溶融しない程
度に予熱し、しかる後母材溶鋼を鋳込むようにしたもの
であシ、かかる構成によシ、合せ材との界面における母
材溶鋼の凝固速度が小さくなることによってスラブ、ス
カム等の異物の浮上性が確保され、それら異物の母材・
合せ材界面への巻き込みが適切に防止される。加えて、
合せ材の過度の再溶解を抑えつつ母材と合せ材とを適切
に溶着接合せしめることができ、鋳造段階で健全な界面
密着性が得られる。合せ材の予熱において、合せ材を再
溶解する程度に過度に加熱すると、製造された鋼塊の母
材溶鋼成分がその厚み方向で変化したシ、合せ材と母材
との界面部に両材質の混合層（成分遷移層）が和尚の厚
みで形成されるという好ましくない結果を招くものであ
ル、これに対し本発明によれば、合せ材紘母材溶鋼と接
触して始めてその表層部が半溶融又は溶融状態となり、
その表層部のみが母材溶鋼と溶融混合し、このため薄い
混合層によシ適切な溶着状態が得られる。For this reason, the present invention uses a heating device to preheat the mating material placed in the mold to the extent that the surface to be joined to the base material is not melted, and then the base material molten steel is poured. In addition, due to this structure, the solidification rate of the base metal molten steel at the interface with the laminate material is reduced, which ensures the levitation of foreign substances such as slabs and scum, and the foreign substances are removed from the base metal.
Entrainment at the interface of the laminate is appropriately prevented. In addition,
The base material and the cladding material can be appropriately welded and bonded while suppressing excessive re-melting of the cladding material, and sound interfacial adhesion can be obtained at the casting stage. During preheating of the laminate, if the laminate is heated excessively to the extent that it is remelted, the molten steel composition of the base material of the manufactured steel ingot may change in the thickness direction, and the interface between the laminate and the base material may be affected by both materials. This results in an undesirable result in that a mixed layer (component transition layer) is formed with a thickness of approximately 100 mm.However, according to the present invention, the surface layer of the laminated material is not formed until it comes into contact with the base material molten steel. becomes semi-molten or molten,
Only the surface layer melts and mixes with the base metal molten steel, so that a suitable welding state is obtained with a thin mixed layer.

第１図は本発明による２　１ｍクラッド鋼塊の一製造工
程例を示すもので、（１）は下注ぎ定盤、（２）はこの
定盤上に設置された鋳型、（３）は湯道煉瓦である。Figure 1 shows an example of the manufacturing process for a 21 m clad steel ingot according to the present invention, in which (1) is a bottom pouring surface plate, (2) is a mold installed on this surface plate, and (3) is a hot water ingot. It is a road brick.

まず同図（イ）に示すように、クラッド用の合せ材（４
）（スラブ）を鋳型（２）内に入れ、鋳型壁に密着する
ようにして固定する。この合せ材（４）は上方からの懸
架、或は鋳型壁や定盤からの支持等、適当な手段により
固定される。First of all, as shown in the same figure (a), the cladding material (4
) (slab) is placed in the mold (2) and fixed so that it is in close contact with the mold wall. This mating material (4) is fixed by appropriate means such as suspension from above or support from a mold wall or surface plate.

なお、合せ材（４）は鋳ｍ壁面に直に密着させる他、合
せ材（４）の熱膨張代を見込んで鋳□型壁との間で間隙
をとシ、この間隙を耐火ボード、耐火モルタル等の耐火
物で塞ぐことによシ鋳型壁に対して密着せしめるように
することができる。上記耐火物は母材溶鋼の鋳込み時に
溶鋼が合せ材（４）の背面に回らないようにシールする
とともに、合せ材熱膨張時の膨張代を吸収する。In addition to directly adhering the cladding material (4) to the mold wall surface, a gap is created between the cladding material (4) and the mold wall in consideration of the thermal expansion allowance of the laminate material (4), and this gap is filled with fireproof board, fireproof board, etc. By sealing it with a refractory material such as mortar, it can be brought into close contact with the mold wall. The refractory material seals the base metal molten steel so that it does not flow to the back surface of the cladding material (4) during casting, and also absorbs the expansion allowance when the cladding material thermally expands.

この状態で鋳型（２）内にパネル状の加熱装置（５）を
吊シ入れ、合せ材（４）に対向するよう、にして位置せ
しめ、合せ材（４）の母材と接合すべき面（４１）　（
以下接合ｆｆｉ　（４１）と称す）を加熱する。In this state, suspend the panel-shaped heating device (5) into the mold (2), position it so as to face the laminate material (4), and place the surface of the laminate material (4) to be joined to the base material. (41) (
The bond ffi (hereinafter referred to as ffi (41)) is heated.

この加熱は上記接合面（４１）が溶融し々い程度の温度
で行われる。この接合面（４１）の加熱は一般に４００
〜１２００°０　の温度域で行われる。温度が４００　
’Ｏ未満では目的とする予熱効果が得られず、また一般
に１２００　゛Ｏ程度を超える温度域では合せ材の溶融
がはじまる。This heating is performed at a temperature that almost melts the joint surface (41). The heating of this joint surface (41) is generally 400
It is carried out in the temperature range of ~1200°0. temperature is 400
If the temperature is less than 1,200 degrees, the desired preheating effect cannot be obtained, and in general, the laminate will start to melt in a temperature range exceeding about 1,200 degrees.

加熱装置（５）としては、気体、液体又は固体燃料等の
燃焼熱、或は電気抵抗加熱等を利用した輻射式加熱装置
が用いられる。As the heating device (5), a radiant heating device using combustion heat of gas, liquid, or solid fuel, electric resistance heating, or the like is used.

また、このような加熱装置（５）の加熱炭による合せ材
加熱面の酸化や浸炭作用を防止するため合せ材（４）の
被加熱面に浸炭或は酸化防止剤を塗布しておくことが好
ましい。Further, in order to prevent oxidation and carburization of the heated surface of the laminate material (4) due to the heated coal of the heating device (5), carburizing or an antioxidant may be applied to the heated surface of the laminate material (4). preferable.

上記加熱後、第１図（ロ）に示すように加熱装置（５）
を鋳型（２）から速やかに取フ出し、合せ材（４）の接
合面（４１）が所定の温度範囲にあるうちに第１図（ハ
）に示すように母材溶鋼（６）を下注ぎで鋳込み、母材
と合せ材（４）とを溶着接合せしめる。After the above heating, as shown in Figure 1 (b), the heating device (5)
Immediately remove it from the mold (2), and lower the base material molten steel (6) as shown in Figure 1 (c) while the joint surface (41) of the mating material (4) is within the specified temperature range. The base material and the laminate material (4) are welded together by pouring.

このような母材溶鋼（６）の鋳込み過程において、合せ
材（４）との界面近傍における母材溶鋼の凝固が前記合
せ材（４）の予熱によって遅らされるため、スラグやス
カム等の異物が浮上する時間的余裕が与えられ、それら
異物の合せ財界面での捕捉が適切に防止される。一方、
予熱されている合せ材（４）の接合面表層部は母材溶鋼
（６）との接触によシ半溶融又は溶融状態となυ、これ
によシ母材溶鋼（６）との適切な界面密着性が得られる
。In the process of casting the base metal molten steel (6), the solidification of the base metal molten steel near the interface with the composite material (4) is delayed by the preheating of the composite material (4), so that slag, scum, etc. This provides time for the foreign objects to float to the surface, and appropriately prevents them from being captured on the composite surface. on the other hand,
The surface layer of the joint surface of the preheated cladding material (4) becomes semi-molten or molten due to contact with the base metal molten steel (6), and this causes appropriate contact with the base metal molten steel (6). Provides interfacial adhesion.

なお、上記合せ材（４）は、その歩留を確保するため、
第４図に示すように鋼塊底部相画郭と上部押湯部にダミ
ー材（７）　（７）を溶接接合しておくことができる。In addition, in order to ensure the yield of the above-mentioned laminated material (4),
As shown in FIG. 4, dummy members (7) (7) can be welded to the bottom phase frame of the steel ingot and the upper feeder section.

すなわち合せ材の材質は一般に高価な材質（例えばＳＵ
Ｂ　）のものが多いが、この合せ材の底部は、下注ぎ鋳
造時の注入流による過度な溶損が本発明の如き予熱の有
無にかかわらず発生するため切断除去されるのが通常で
あシ、シたがって、この部分を一般鋼等の安価なダ建−
材（７）としておく。In other words, the material of the laminate is generally an expensive material (for example, SU
B) is common, but the bottom of this composite material is usually cut and removed because excessive erosion due to the injection flow during bottom pour casting occurs regardless of whether preheating is performed as in the present invention. Therefore, this part should be constructed using inexpensive materials such as general steel.
Leave it as material (7).

また合せ材の上部に相当する部分も分塊時にクロップと
して切断除去されるものであシ、したがって、この部分
も安価なダミー材（７）としておく。なお、同様の理由
によシ合せ材の側部にもダミー材（図示せず〕を接合し
ておくこともできる。Further, the part corresponding to the upper part of the laminate is also cut off and removed as a crop during blooming, so this part is also made into an inexpensive dummy material (7). Incidentally, for the same reason, a dummy material (not shown) can also be joined to the side part of the joining material.

なお、合せ材の上下及び両側の４辺に母材と同等の成分
系を有するダミー材を所定幅で設けるととによシ、分塊
圧延時の母材７合せ材の接合性をよシ強固なものとし、
合せ材と母材（例えば８Ｕ８と一般Ｃ＠）間の変形抵抗
の違いによる圧延中の剥離を適切に防止せしめることが
できる。In addition, it is advisable to provide dummy materials having the same composition as the base material at a specified width on the four sides of the top, bottom, and both sides of the laminate. Make it strong;
Peeling during rolling due to the difference in deformation resistance between the laminate and the base material (for example, 8U8 and general C@) can be appropriately prevented.

第２図は２層クラッド鋼塊の他の製造例を示すもので、
合せ材（４）の設置位置を鋳型壁から離し、合せ材（４
）の接合面（４１）の予熱を合せ材（４）の背面側から
行うようにしたものである。Figure 2 shows another example of manufacturing a two-layer clad steel ingot.
Move the installation position of the cladding material (4) away from the mold wall, and
), the joint surface (41) is preheated from the back side of the laminate (4).

このような方法によル、り２ツド鋼板のクラツド比（全
厚に占める合せ材厚みの比）が適宜変更でき、目的に応
じた鋼塊を製造することができる。By such a method, the cladding ratio (the ratio of the thickness of the laminated material to the total thickness) of the steel plate can be changed as appropriate, and a steel ingot can be manufactured according to the purpose.

鋳型壁から離された合せ材（４）は鋳型（２）の上部に
取付けた固定支持枠（８）によシ支持され、この合せ材
（４）の背面側の鋳型内空間（Ｓ、）に加熱装置（５）
が位置せしめられ、合せ材（４）が予熱される。この予
熱後、反対側の間（Ｓ＋）に母材溶鋼（６）が鋳込まれ
る。The cladding material (4) separated from the mold wall is supported by a fixed support frame (8) attached to the upper part of the mold (2), and the mold interior space (S,) on the back side of this cladding material (4) heating device (5)
is positioned and the laminate (4) is preheated. After this preheating, the base material molten steel (6) is cast between the opposite sides (S+).

第３図鉱３層クラッド鋼塊（合せ材が２層の鋼塊）の製
造例を示すもので、鋳型（２）の対向する壁にそれぞれ
合せ材（４ａ）　（４ｂ）を配置し、両合せ材（４ａ）
　（４ｂ）間に加熱装置（５）を挿入してそれぞれを予
熱し、しかる後加熱装置（５）を搬出して母材溶鋼の鋳
込みを行うものである。この際の合せ材（４）の固定方
法等は詑１図に示す如き実施例のものと同様である。Figure 3 shows an example of manufacturing a three-layer clad steel ingot (a steel ingot with two layers of cladding material), in which cladding materials (4a) and (4b) are placed on opposing walls of the mold (2), and both Laminating material (4a)
A heating device (5) is inserted between (4b) to preheat each, and then the heating device (5) is taken out and the base metal molten steel is poured. The method of fixing the laminate (4) at this time is the same as that of the embodiment shown in Fig. 1.

◎実施例 １５トン鋼塊を得る下注ぎ鋳型６本を下注ぎ用定盤に据
え、合せ材として５ＵＢ−３０４，母材として４０キロ
級Ａｔ−５ｔキルド鋼をそれぞれ用い、第１図及び第２
図に示す本発明法と第５図に示す従来法によシそれぞれ
クラッド鋼塊を製造した。なお第５図に示す従来法は、
２枚重ねの合せに懸架せしめ、母材鋳込み・凝固後、分
塊圧延、板圧延し、しかる後、重合した合せ鋼板を得る
ようにする方法である。◎Example 1 Six bottom pouring molds for obtaining a 5-ton steel ingot were placed on a bottom pouring surface plate, 5UB-304 was used as the mating material, and 40kg At-5t killed steel was used as the base material. 2
Clad steel ingots were produced by the method of the present invention shown in the figure and by the conventional method shown in FIG. The conventional method shown in Figure 5 is as follows:
This is a method in which two sheets are stacked and suspended, and after base material casting and solidification, blooming and plate rolling are performed, and then a polymerized laminated steel sheet is obtained.

以上の本発明法及び従来法の製造条件は以下の通シであ
る。The manufacturing conditions for the method of the present invention and the conventional method described above are as follows.

鋳造条件 注湯溶鋼温度：　１５８０〜１５９０°０鋳型内湯上シ
速度：平均４００ｍ１ｍ１ｎ合せ材加熱条件（本発明法
） 予熱時間：９０〜１２０ｍｉｎ 予熱温度＝４００〜１１００　’０ 以上の条件で鋼塊を製造し、との鋼塊を分塊圧延してス
ラブとなし、このスラブ段階ての合せ材の接着性及び界
面清浄性を超音波探傷法によシ調べた。その結果を第１
表に示す。Casting conditions Pouring molten steel temperature: 1580-1590°0 Temperature of hot water in the mold: Average 400m1m1n Laminated material heating conditions (method of the present invention) Preheating time: 90-120min Preheating temperature = 400-1100°C Steel ingots were poured under the following conditions: The manufactured steel ingot was bloomed into a slab, and the adhesion and interface cleanliness of the laminate at the slab stage were examined using ultrasonic flaw detection. The result is the first
Shown in the table.

第１表 ※・・・供試スラブ本数各６本（２鋼塊分）また下記第
２表は上記スラブを更に鋼板まで成品圧延し、その歩留
を比較して示したものである。Table 1*: Number of test slabs: 6 each (2 steel ingots) Also, Table 2 below shows a comparison of the yields of the above slabs further rolled into finished steel plates.

第　２　表 このように本発明法では、従来法に較べ母材７合せ材界
面の接着性と清浄性に優れたクラッド鋼塊が得られてお
シ、また、これによシー貫歩留も向上していることが判
る０〔発明の効果〕 以上述べた本発明によれば、母材と合せ材の界面への異
物巻き込みを適切に防止することができるとともに、母
材溶鋼成分がその厚み方向で変化したシ、合せ材と母材
との界面部に両材質が混合した厚い成分遷移層が形成さ
れたシすることなく合せ材と母材との適切な溶着状態を
得ることができこのようなことがらり２ツド鋼板の製品
品質とその一買歩留を従来に較べ大きく向上させること
ができる。Table 2 As can be seen from the above, the method of the present invention yields a clad steel ingot with superior adhesion and cleanliness at the interface between the base metal and laminate materials compared to the conventional method. 0 [Effects of the Invention] According to the present invention described above, it is possible to appropriately prevent foreign matter from being entrapped at the interface between the base material and the laminate, and the molten steel components of the base material are This makes it possible to obtain an appropriate welding state between the cladding material and the base material without forming a thick component transition layer where both materials are mixed at the interface between the cladding material and the base material. This makes it possible to greatly improve the product quality of double-sided steel sheets and the yield per purchase compared to the past.

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

第１図（イ）ないしく口）は本発明を２層り２ツド鋼塊
の製造に適用した場合の一実施例を段階的に示す説明図
である。第２図は同じく他の実施例を示す説明図である
。第３図は本発明を３層り２ツド鋼塊の製造に適用した
場合の一実施例を示す説明図である。第４図は本発明法
で使用される合せ材の一例を示す斜視図である。第５図
は従来のクラッド鋼塊製造法を示す説明図である。 図において、（１）は定盤、（２）は部屋、（４）　。 （４ａ）　ｅ　（４ｂ）は合せ材、（４っけ接合面、（
５）は加熱装置、（６）は母材溶鋼を各示す。 特許出願人　日本鋼管株式会社 発　明　者　半　明　正　２ 同　寺　１）　作 間　水　岡　誠　史 同　宮　原　思 量　麦　１）　幹　雄 同　鈴　木　真 代理人弁理士　吉　原　省　三 同　同　高　橋　清 同　弁膜士　吉　原　弘　子 第１図 （ロ） （八） ｗｔ、２図 Ｉ！３図 第５ｍ 第４図 手続補正書彷式） 昭和５７年ｅ月７日 特許庁長官　志　賀　学　殿 （特許庁審査官　殿） ■、事件の表示 昭和Ｓ９　年　待　許　願第　ｙ７ｂｏｑ　号２発明の
名称 クク、ソド＠＊の塚五カつ較 （４１２）　日本鋼管株式会社 ４代理人 ５、補正命令の日付 昭和、５ｑ年７月ｌ１日 ７補正の内容　別紙のとおり 補　正　内　容 １本願明細書中年１３頁１３行目冒頭に「第１図〔イ〕
ないしく口）」とらるを「第１図（イ）ないしＱ・）」
　と訂正する。FIGS. 1(a) to 1(a) are explanatory diagrams showing step-by-step an embodiment in which the present invention is applied to the production of a two-layer, two-piece steel ingot. FIG. 2 is an explanatory diagram showing another embodiment. FIG. 3 is an explanatory diagram showing an embodiment in which the present invention is applied to the production of a three-layer, two-piece steel ingot. FIG. 4 is a perspective view showing an example of a laminate used in the method of the present invention. FIG. 5 is an explanatory diagram showing a conventional clad steel ingot manufacturing method. In the figure, (1) is a surface plate, (2) is a room, and (4) is. (4a) e (4b) is the cladding material, (4-piece joint surface, (
5) shows the heating device, and (6) shows the base metal molten steel. Patent Applicant: Nippon Kokan Co., Ltd. Inventor: Masaaki Hanaki 2 Doji Temple 1) Makoto Sakuma Mizuoka Fumito Mugi Miyahara 1) Yudo Miki Makoto Suzuki Patent Attorneys Sho Yoshihara Sando Kiyoshi Takahashi Hiroko Yoshihara, the same valvular specialist Figure 1 (B) (8) wt, Figure 2 I! (Figure 3, Figure 5m, Figure 4, Procedural Amendment Form) September 7, 1980 Manabu Shiga, Commissioner of the Patent Office (Examiner of the Patent Office) ■Indication of the case 1982 Patent Application No. Y7BOQ 2 Invention Name of Kuku, Sodo@* Nozuka Gokatsukai (412) Nippon Kokan Co., Ltd. 4 Agent 5 Date of amendment order Showa, July 11, 5q 7 Contents of amendment As shown in the attached sheet Amendment contents 1 Main application At the beginning of page 13, line 13 of the specification, it says “Figure 1 [A]
Toraru is "Figure 1 (a) or Q.)"
I am corrected.

Claims (2)

【特許請求の範囲】[Claims] （１）　鋳型内に合せ材たるスンプ又拡厚板を位置せし
めた後、母材溶鋼を鋳込んで合せ材と母材とを溶着せし
めクラッド鋼塊を製造する方法において、加熱装置にょ
シ、鋳型内に位置せしめられた合せ材の母材と接合すべ
き面を溶融しなｉ程度に予熱し、しかる後母材溶鋼を鋳
込むことを特徴とするクラッド鋼塊の製造方法。(1) In a method of manufacturing a clad steel ingot by placing a sump or an expansion plate as a cladding material in a mold, and then pouring base material molten steel and welding the cladding material and the base material, the heating device is heated, A method for manufacturing a clad steel ingot, which comprises preheating a surface of a cladding material placed in a mold to be joined to a base material to a temperature that does not melt the surface, and then pouring molten steel into the base material. （２）合せ材の被加熱面に予め浸炭防止剤を塗布してお
くことを特徴とする特許請求の範囲（１）記載のクラッ
ド鋼塊の製造方法。(2) The method for manufacturing a clad steel ingot according to claim (1), characterized in that a carburization inhibitor is applied in advance to the heated surface of the laminate.