JPS6121742B2 - - Google Patents
Info
- Publication number
- JPS6121742B2 JPS6121742B2 JP14706480A JP14706480A JPS6121742B2 JP S6121742 B2 JPS6121742 B2 JP S6121742B2 JP 14706480 A JP14706480 A JP 14706480A JP 14706480 A JP14706480 A JP 14706480A JP S6121742 B2 JPS6121742 B2 JP S6121742B2
- Authority
- JP
- Japan
- Prior art keywords
- mold
- steel
- short
- insulating material
- heat insulating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 35
- 239000010959 steel Substances 0.000 claims description 35
- 238000007711 solidification Methods 0.000 claims description 11
- 230000008023 solidification Effects 0.000 claims description 11
- 239000011810 insulating material Substances 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 5
- 238000000034 method Methods 0.000 description 13
- 238000005266 casting Methods 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Description
本発明は、高さに比較して横幅の広い扁平な縦
短鋼塊を製造するに当り、特に内質のすぐれた鋼
塊を製造する方法に関する。
通常、鋼塊から製造される鋼板類は、正錐また
は逆錐形の縦長の鋳型に鋳込んで造塊した後、鋼
塊を長手方向に圧延して成形されるため、鋼塊の
鋳込方向に垂直な方向が圧下方向となり、結果的
には鋼塊の板厚方向となる。
しかしながら、従来の縦長の鋼塊では下注、上
注を間わず、冷却が主として鋳型側壁をかいして
行われるため、例えば下注逆錐形のキルド鋼塊に
おいては、鋼塊頭部にC.S.P等の濃厚偏析部が発
生したり、心部には凝固時の体積収縮に起因する
ポーラスなザク巣が発生するなど、種々の欠陥の
発生が避けられない。
そこで、鋳型内に注入された溶鋼が鋳型底面か
ら上方に向かつて順次層状に凝固するいわゆる一
方向凝固を行う造塊法が近年開発されてきた。特
に本出願人による特願昭54−110951に係る「鋼塊
内質向上のための制御方法」は、鋼塊の内質を向
上する一方向凝固を可能にする製造方法であつ
て、造塊作業費と歩留損失を大幅に低減しうる有
効な手段となつている。
第１図によつて説明すると、定盤１上に鋳型枠
体（以下、鋳型という）２を設置し鋳型２内に溶
鋼７を注入する。鋳型２は扁平なものを用い、鋳
型２の内側壁全面を所定の厚みの断熱材３で被覆
する。断熱材３の働きは、溶鋼が保有する熱量が
鋳型側壁に伝達するのを防止する。この方法によ
つて得られた縦短鋼塊は、底面方向からの一方向
凝固の性状を有することとなるため、内部品質の
すぐれた鋼塊となる。しかしながら、この鋼塊は
従来の造塊法に比較して大断面積を有するもので
あるので凝固収縮量が大きくなることは免れず、
鋳込み後において鋳型２と断熱材３との間にエア
ギヤツプS1が生ずる。定盤１も鋼塊断面に対応し
て大きいものであるので、反り量が大きくなり、
鋳型２のコーナ側と接する部分には、反りによる
ギヤツプS2が生じる傾向がある。このため、ギヤ
ツプS2とS1とによる通気路（煙突の作用に相当す
るもの）が形成されて外部の空気が吸引され、わ
ずかながらも側面方向からの凝固が進行する傾向
を生じ、鋼塊のゴースト生成を促進する結果とな
る。
したがつて、本発明の目的は、例えわずかとい
えども側面方向から凝固する傾向を抑制する手段
を提供して一方向凝固を達成させ、これにより一
層内質のすぐれた縦短鋼塊を得ることにある。
本発明の主眼は、縦短鋼塊を造塊する鋳型にお
いて避けることのできない熱膨張率に伴うエア・
ギヤツプに対して、外気の侵入を遮断させ、これ
による多方向凝固の傾向を防止させることにあ
る。
本発明の方法は、第２図に示すように定盤１、
鋳型２および断熱材３から成る縦短鋳型におい
て、鋳型２からやや離れた定盤上の位置に、鋳型
２を囲繞するように薄鉄板の外枠５を棚状に設
け、鋳型２の基端側の周囲にあたかも溝を形成さ
せ、この溝に川砂またはキヤスタブル等のSiO2
を主成分とする粒度３mm以下の耐熱性粉体６を
150mm程度の層厚で充填収容させる。これによ
り、溶鋼注入後において、定盤１と鋳型２との間
に生ずるギヤツプS2の外気側を粉体６で遮断し、
ギヤツプS1とS2とによつて生ずる外気流通による
煙突作用を防止する。
次に、本発明の造塊方法の実施例について説明
する。使用した溶鋼成分および鋳型内寸法をそれ
ぞれ第１表および第２表に示す。第２図に示す縦
短鋳型において、鋳型基端部の外周の溝（幅70mm
×高さ200mm）に砂を充填収容し、溶鋼を鋳込ん
だ。断熱料は鋲打銃により鋳型壁に鋲止めした。
鋳型厚みは250mm、断熱材の厚みは70mmであつ
て、鋳込み高さは800mmとした。注入完了後に粒
度１〜15mmの保温材を約７Kg／溶鋼トン投入し
た。断熱材および保温材の成分をそれぞれ第３表
および第４表に示す。また、定盤寸法および材質
を第６表および第７表にならびに鋳型材質を第８
表にそれぞれ示す。
本発明法と、耐熱性粉体の付設をせずに鋳込ん
だ従来法とを比較するために、それぞれの方法に
よつて造塊の中央部を切断してその切断面をダイ
チエツクによりミクロ・キヤビテイの発生状態
を、またマイクロ・チエツクによりゴーストの発
生状態をそれぞれ検査した。ミクロ・キヤビテイ
の発生状態を第４図に示す。その結果、ミクロ・
キヤビテイの発生状況は第５表に示されるとおり
大幅に軽減され、後工程の分塊および厚板圧延で
は圧下比3.5以上にて十分な圧着状態を得る。ゴ
ースト発生状態は第３図に示す。鋼塊側端からみ
たゴースト発生始点の位置ａを●またはΓ印と
し、終点の位置ｂを▲または△印とすると、本発
明法による場合（●▲）は、従来法の場合（Γ
△）に比較して端部寄りに狭い範囲で生成されて
おり、改善の効果が顕著であつた。
以上の説明によつて明らかなように、本発明の
方法によれば、一方向凝固の傾向を一層確実なも
のとすることができるので、縦短鋼塊の品質は一
層改善され、内質のすぐれた鋼塊を得ることがで
きる。
The present invention relates to a method for producing a flat steel ingot with a wide width compared to its height, and particularly to a method of producing a steel ingot with excellent internal quality. Normally, steel plates manufactured from steel ingots are formed by casting the steel ingot into a vertically elongated mold with a regular or inverted conical shape, and then rolling the steel ingot in the longitudinal direction. The direction perpendicular to this direction is the rolling direction, which ultimately becomes the thickness direction of the steel ingot. However, with conventional vertically long steel ingots, cooling is mainly done through the side wall of the mold without any time between bottom pouring and top pouring. The occurrence of various defects is unavoidable, such as the occurrence of densely segregated areas such as CSP, and the occurrence of porous cavities in the core due to volumetric contraction during solidification. Therefore, a so-called unidirectional solidification method has been developed in recent years in which molten steel poured into a mold is solidified sequentially in layers from the bottom of the mold upward. In particular, the "control method for improving the internal quality of steel ingots" related to Japanese Patent Application No. 54-110951 filed by the present applicant is a manufacturing method that enables unidirectional solidification to improve the internal quality of steel ingots. This is an effective means of significantly reducing work costs and yield losses. To explain with reference to FIG. 1, a mold frame body (hereinafter referred to as a mold) 2 is placed on a surface plate 1, and molten steel 7 is poured into the mold 2. A flat mold 2 is used, and the entire inner wall of the mold 2 is covered with a heat insulating material 3 having a predetermined thickness. The function of the heat insulating material 3 is to prevent the amount of heat held by the molten steel from being transmitted to the side walls of the mold. The vertically short steel ingot obtained by this method has the property of unidirectional solidification from the bottom surface direction, and therefore becomes a steel ingot with excellent internal quality. However, since this steel ingot has a larger cross-sectional area compared to the conventional ingot-forming method, it is inevitable that the amount of solidification shrinkage will increase.
After casting, an air gap S1 is created between the mold 2 and the heat insulating material 3. Since the surface plate 1 is also large in proportion to the cross section of the steel ingot, the amount of warpage increases,
There is a tendency for a gap S 2 to occur due to warpage at the portion of the mold 2 that contacts the corner side. For this reason, a ventilation path (corresponding to the effect of a chimney) is formed by gaps S 2 and S 1 , and outside air is sucked in, causing a tendency for solidification to proceed from the side, albeit slightly, and the steel ingot. This results in promoting the generation of ghosts. Therefore, an object of the present invention is to provide a means for suppressing the tendency of solidification from the side direction, even if only slightly, to achieve unidirectional solidification, thereby obtaining a longitudinal and short steel ingot with even better internal quality. There is a particular thing. The main focus of the present invention is the air loss associated with the coefficient of thermal expansion that is unavoidable in molds for forming vertical and short steel ingots.
The purpose is to block the intrusion of outside air into the gap and prevent the tendency of multidirectional solidification caused by this. In the method of the present invention, as shown in FIG.
In a vertical and short mold consisting of a mold 2 and a heat insulating material 3, an outer frame 5 made of a thin iron plate is provided in the shape of a shelf at a position slightly away from the mold 2 on a surface plate so as to surround the mold 2, and the base end of the mold 2 is Form a groove around the side, and fill this groove with SiO 2 such as river sand or castable.
A heat-resistant powder 6 with a particle size of 3 mm or less whose main component is
It is filled with a layer thickness of about 150mm. As a result, after pouring molten steel, the outside air side of the gap S 2 that occurs between the surface plate 1 and the mold 2 is blocked by the powder 6,
The chimney effect caused by the outside air circulation caused by the gaps S 1 and S 2 is prevented. Next, an example of the agglomeration method of the present invention will be described. The components of the molten steel used and the mold internal dimensions are shown in Tables 1 and 2, respectively. In the vertical and short mold shown in Fig. 2, there is a groove (width 70 mm) on the outer periphery of the base end of the mold.
x height 200 mm) was filled with sand and molten steel was cast. The insulation was tacked to the mold wall using a tack gun.
The mold thickness was 250 mm, the insulation material thickness was 70 mm, and the casting height was 800 mm. After the injection was completed, approximately 7 kg/ton of molten steel was added to the heat insulating material with a grain size of 1 to 15 mm. The components of the heat insulating material and heat retaining material are shown in Tables 3 and 4, respectively. In addition, table dimensions and materials are shown in Tables 6 and 7, and mold materials are shown in Tables 8.
Each is shown in the table. In order to compare the method of the present invention with the conventional method of casting without adding heat-resistant powder, the central part of the ingot was cut using each method, and the cut surface was micro-shaped using a die check. The occurrence of cavities and the occurrence of ghosts were examined by micro-check. Figure 4 shows how micro cavities occur. As a result, micro-
The occurrence of cavities is significantly reduced as shown in Table 5, and a sufficient crimping condition is obtained at a reduction ratio of 3.5 or more in the later processes of blooming and thick plate rolling. The state of ghost occurrence is shown in FIG. If the position a of the starting point of ghost occurrence seen from the side edge of the steel ingot is marked with ● or Γ, and the position b of the end point is marked with ▲ or △, then in the case of the present method (●▲), in the case of the conventional method (Γ
Compared to △), it was generated in a narrower range near the end, and the improvement effect was remarkable. As is clear from the above explanation, according to the method of the present invention, the tendency of unidirectional solidification can be further ensured, so that the quality of longitudinal and short steel ingots is further improved, and the internal quality is Excellent steel ingots can be obtained.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
【表】【table】
第１図は一部を誇張して示す縦短鋼塊製造の従
来方法の説明図。第２図は本発明の方法の第１図
同様の説明図。第３図は本発明と従来法との効果
の比較を示すゴースト発生分布図。第４図はミク
ロ・キヤビテイの発生状態を示す鋼塊の長手方向
断面図。
１：定盤、２：縦短鋳型、３：断熱材、４：保
温材、６：耐熱性粉体、７：溶鋼。
FIG. 1 is an explanatory diagram of a conventional method for manufacturing vertical and short steel ingots, with some parts exaggerated. FIG. 2 is an explanatory diagram similar to FIG. 1 of the method of the present invention. FIG. 3 is a ghost generation distribution diagram showing a comparison of the effects of the present invention and the conventional method. FIG. 4 is a longitudinal cross-sectional view of a steel ingot showing the state in which micro cavities are generated. 1: surface plate, 2: vertical and short mold, 3: heat insulating material, 4: heat insulating material, 6: heat resistant powder, 7: molten steel.
Claims (1)
壁を断熱材で被覆し、該鋳型内に溶鋼を注入し、
溶鋼上面を保温材で被覆して鋼塊底部からの一方
向凝固を促進させる縦短鋼塊の製造にあたり、鋳
型枠体の基端部側外周部と定盤との接合部にそつ
て耐熱性粉体を充填収容する溝を設け、前記接合
部から鋳型枠体の内側への外気の流通を遮断させ
るようにしたことを特徴とする内質のすぐれた縦
短鋼塊の製造方法。1. Covering the inner wall of a vertical and short mold that combines a surface plate and a mold frame with a heat insulating material, injecting molten steel into the mold,
When manufacturing vertical and short steel ingots, in which the top surface of molten steel is coated with a heat insulating material to promote unidirectional solidification from the bottom of the steel ingot, heat resistance is A method for producing a vertical and short steel ingot with excellent internal quality, characterized in that a groove is provided to fill and accommodate powder, and the flow of outside air from the joint to the inside of the mold frame is blocked.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14706480A JPS5770079A (en) | 1980-10-21 | 1980-10-21 | Production of longitudinally short steel ingot |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14706480A JPS5770079A (en) | 1980-10-21 | 1980-10-21 | Production of longitudinally short steel ingot |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5770079A JPS5770079A (en) | 1982-04-30 |
| JPS6121742B2 true JPS6121742B2 (en) | 1986-05-28 |
Family
ID=15421664
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14706480A Granted JPS5770079A (en) | 1980-10-21 | 1980-10-21 | Production of longitudinally short steel ingot |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5770079A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60153828U (en) * | 1984-03-23 | 1985-10-14 | 三菱電機株式会社 | Engine auxiliary drive device |
| CN102240797A (en) * | 2010-05-13 | 2011-11-16 | 辽宁科技大学 | Device for insulating side wall of directional solidified steel ingot |
-
1980
- 1980-10-21 JP JP14706480A patent/JPS5770079A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5770079A (en) | 1982-04-30 |
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