JPH04187346A - Method for continuously casting thin cast strip - Google Patents
Method for continuously casting thin cast stripInfo
- Publication number
- JPH04187346A JPH04187346A JP31591290A JP31591290A JPH04187346A JP H04187346 A JPH04187346 A JP H04187346A JP 31591290 A JP31591290 A JP 31591290A JP 31591290 A JP31591290 A JP 31591290A JP H04187346 A JPH04187346 A JP H04187346A
- Authority
- JP
- Japan
- Prior art keywords
- molten metal
- roll
- gas
- cooling
- cast strip
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 12
- 238000005266 casting Methods 0.000 title description 10
- 239000002184 metal Substances 0.000 claims abstract description 24
- 238000001816 cooling Methods 0.000 claims abstract description 22
- 238000009749 continuous casting Methods 0.000 claims description 9
- 230000002745 absorbent Effects 0.000 claims description 3
- 239000002250 absorbent Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000007711 solidification Methods 0.000 abstract description 5
- 230000008023 solidification Effects 0.000 abstract description 5
- 238000005096 rolling process Methods 0.000 abstract description 2
- 238000002347 injection Methods 0.000 abstract 1
- 239000007924 injection Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 23
- 239000011261 inert gas Substances 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、薄鋳片の連続鋳造方法に関し、とくに双ロ
ール法によって表面性状の良好な薄鋳片を製造しようと
するものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous casting method for thin cast slabs, and is particularly directed to producing thin cast slabs with good surface properties by a twin roll method.
近年、溶融金属を、相対して互いに逆方向に回転する1
対の冷却ロール間に供給し急冷凝固させて薄鋳片とする
、いわゆる薄帯直接鋳造法が開発され、省工程、歩留り
の向上および初期設備投資の削減等が達成できるところ
から、注目を集めている。In recent years, 1) rotating molten metal in opposite directions to each other
The so-called direct casting method of thin strips was developed, in which the thin strips are fed between a pair of cooling rolls and rapidly solidified into thin strips.This method has attracted attention because it can save process steps, improve yields, and reduce initial capital investment. ing.
かかる薄帯直接鋳造法の実現には、注湯技術、鋳造技術
、巻取搬送技術、品質向上、後工程技術および鋼種拡大
等の課題があり、中でも品質向上、特に鋳片の表面性状
の改善に対する要請が強い。In order to realize this method of direct thin strip casting, there are issues such as pouring technology, casting technology, winding and conveying technology, quality improvement, post-process technology, and expansion of steel types. There is a strong demand for
すなわち、得られる鋳片の表面に、割れや細かいひび割
れ又は不均一な凹凸のないことが肝要である。That is, it is important that the surface of the slab obtained be free of cracks, fine cracks, or uneven unevenness.
良好な表面性状の鋳片を得るには、例えば゛特開昭59
−199152号、同60−170562号および同6
2−130749号各公報に示されているように、冷却
ロール間の溶融金属の湯溜り部表面を不活性ガス雰囲気
にして大気と遮断することによって、酸化物の生成を防
止することが有効な手段である。というのは、溶融金属
表面に酸化物が生成すると、この酸化物がロール面に帯
同されて巻き込まれ、ロールと溶融金属との間に介在し
冷却むらを招き、鋳片の表面性状が劣化するからである
。In order to obtain slabs with good surface properties, for example,
-199152, 60-170562 and 6
2-130749, it is effective to prevent the formation of oxides by creating an inert gas atmosphere on the surface of the pool of molten metal between the cooling rolls and shielding it from the atmosphere. It is a means. This is because when oxides are generated on the surface of the molten metal, these oxides are entrained on the roll surface and become entangled, intervening between the roll and the molten metal, causing uneven cooling and deteriorating the surface quality of the slab. It is from.
上記の不活性ガス雰囲気中の鋳造は、酸化物の生成を抑
制する上で有効であるが、一方でこの不活性ガスがロー
ルの回−転に帯同して溶融金属中に巻き込まれ、ロール
面と溶融金属との間に介在して冷却むらを引き起こすた
め、依然として良好な表面性状の鋳片を得るには到って
いない。Casting in an inert gas atmosphere is effective in suppressing the formation of oxides, but on the other hand, this inert gas is entrained in the molten metal as the rolls rotate, causing It is still not possible to obtain slabs with good surface quality because they are interposed between the metal and the molten metal and cause uneven cooling.
そこでこの発明は、上記の不活性ガスに起因した冷却む
らを、溶融金属の大気遮断を阻害子ることなしに回避す
るための方法について提案することを目的とする。Therefore, an object of the present invention is to propose a method for avoiding the uneven cooling caused by the above-mentioned inert gas, without hindering the blocking of the molten metal from the atmosphere.
この発明は、相対して回転する1対の冷却ロール間の湯
溜り部に溶融金属を供給し、その冷却ロール面上で連続
的に急冷凝固させて薄鋳片を製造するに当たり、上記冷
却ロール対およびこれらのロール間に供給した溶融金属
の表面に対し、吸収性ガスの含有率が5Q vol%以
上の雰囲気ガスを供給することを特徴とする薄鋳片の連
続鋳造方法である。This invention provides a method for producing a thin slab by supplying molten metal to a pool between a pair of cooling rolls that rotate oppositely and continuously quenching and solidifying it on the surface of the cooling roll. This continuous casting method for thin slabs is characterized in that an atmospheric gas having an absorbent gas content of 5Q vol% or more is supplied to the surface of the molten metal supplied between the pair of rolls and these rolls.
さて、第1図に、この発明の方法に直接使用する双ロー
ル式の薄帯直接連続鋳造装置を示す0図中1a、 lb
は内部を水冷された中空円筒状の冷却ロールで、冷却ロ
ールl a 、 1 b ra’lΦロールキス部へ向
けて、供iノズルから溶融金属3を供給してロール間に
湯溜り部3aを形成し、ロール面での急冷凝固を強いて
薄鋳片4を製造するものである。Now, Fig. 1 shows a twin-roll direct continuous ribbon casting apparatus used directly in the method of the present invention.
is a hollow cylindrical cooling roll whose inside is water-cooled, and molten metal 3 is supplied from a supply nozzle toward the cooling roll l a , 1 b ra'lΦ roll kissing part to form a pool part 3 a between the rolls. Then, the thin slab 4 is produced by forcing rapid cooling and solidification on the roll surface.
また、冷却ロールla、 lbの上側および湯溜り部3
aを気密下に覆う密閉蓋5を設置し、この密閉蓋5内に
供給管6から雰囲気ガスを導入して大気と置換する。そ
して鋳造中は、冷却ロールla、 lbおよび湯溜り部
3aへ向けて配置した複数のノズル7a〜7dから雰囲
気ガスを供給する。ノズル78〜7dは、第2図に示す
ようなバイブ8aの周面に一列に並ぶスリット8bを形
成したものを、その軸方向が冷却ロールの軸方向と平行
になるように配置する。In addition, the upper side of the cooling rolls la and lb and the sump portion 3
A hermetically sealed lid 5 is installed to airtightly cover the container a, and atmospheric gas is introduced into the hermetically sealed lid 5 from a supply pipe 6 to replace the atmosphere. During casting, atmospheric gas is supplied from a plurality of nozzles 7a to 7d arranged toward the cooling rolls la, lb and the sump 3a. The nozzles 78 to 7d are formed by forming slits 8b arranged in a row on the circumferential surface of a vibrator 8a as shown in FIG. 2, and are arranged so that the axial direction thereof is parallel to the axial direction of the cooling roll.
さらに、第3図は、第1図の縦型の連続鋳造機を横型に
した例であり、この場合も第1図に示したところと同様
の鋳造を行うことができる。Further, FIG. 3 shows an example in which the vertical continuous casting machine of FIG. 1 is changed to a horizontal type, and in this case as well, the same casting as shown in FIG. 1 can be performed.
二二で、密閉蓋5内に導入し、また鋳造中にノズル7a
〜7dから供給する雰囲気ガスは、吸収性ガスを60シ
o1%以上は含有していることが肝要である。吸収性ガ
スとは、溶鋼との反応性を有し、さらに酸化物の発生を
招かないものでなければならない、また、溶鋼がその吸
収性ガスに対して0.1cm”/ g以上の吸収能をも
つものでなければならない。具体的には、CO,H!、
HCI、 SOx、 Nz、 Nz+Ib。At step 22, the nozzle 7a is introduced into the sealing lid 5 and during casting.
It is important that the atmospheric gas supplied from 7d to 7d contains 60 to 1% or more of absorbing gas. The absorbent gas must be reactive with the molten steel and must not cause the generation of oxides, and the molten steel must have an absorption capacity of 0.1 cm"/g or more for the absorbable gas. It must have CO, H!,
HCI, SOx, Nz, Nz+Ib.
C1□およびH,S等が有利に適合し、混合ガスとする
場合の残部ガスは溶鋼の酸化を防止するために、酸素を
含まないガスであればいずれのガスでもよい。C1□, H, S, etc. are advantageously suitable, and the remaining gas in the case of forming a mixed gas may be any gas that does not contain oxygen in order to prevent oxidation of the molten steel.
なお、雰囲気ガスは、板の表面積1m1z当たり101
の流量で吹付けることが好ましく、さらに、ロール表面
に吸着させるために、ロール面に沿ってガス管を配置す
る必要がある。In addition, the atmospheric gas is 101 per 1 m1z of the surface area of the plate.
It is preferable that the gas be sprayed at a flow rate of 100 ml, and furthermore, it is necessary to arrange a gas pipe along the roll surface in order to cause the gas to be adsorbed onto the roll surface.
薄鋳片の連続鋳造を、Arガス等の不活性ガス雰囲気下
で行うと、第4図に示すように、溶融金属3表面付近に
供給された不活性ガスGは冷却ロール1aの回転面に帯
同して溶融金属3内に巻き込まれ、このロール表面に付
着した不活性ガスGはロール表面と溶融金属3およびそ
の凝固シェル3bとの間に介在することになる。すると
ロール表面には、溶融金属3と直接接触する部分Aおよ
びガス介在下で間接的に接触する部分Bができ、ロール
表面での凝固速度は不均一となる。従って、ロール表面
の凝固は直接接触部分Aで優先して進行する一方、間接
接触部分Bで遅れて進行するため、この部分Bに応力が
集中し、得られる鋳片に割れが発生する。When continuous casting of thin slabs is performed in an inert gas atmosphere such as Ar gas, as shown in Fig. 4, the inert gas G supplied near the surface of the molten metal 3 hits the rotating surface of the cooling roll 1a. The inert gas G that is entrained in the molten metal 3 and attached to the roll surface is interposed between the roll surface and the molten metal 3 and its solidified shell 3b. Then, on the roll surface, a part A that comes into direct contact with the molten metal 3 and a part B that comes into indirect contact with the molten metal 3 are formed, and the solidification rate on the roll surface becomes non-uniform. Therefore, solidification of the roll surface progresses preferentially in the direct contact area A, but progresses later in the indirect contact area B, so stress is concentrated in this area B, and cracks occur in the resulting slab.
これに対して、この発明に従う方法は、主に吸収性ガス
からなる雰囲気ガスを用いるため、第5図に示すように
、冷却ロール1aの回転面に帯同して溶融金属3中に巻
き込まれる雰囲気ガスFは溶融金属3およびその凝固シ
ェル3bに吸収され、ロール面と溶融金属3との間に介
在することはない。On the other hand, the method according to the present invention uses an atmospheric gas mainly consisting of an absorbing gas, so as shown in FIG. The gas F is absorbed by the molten metal 3 and its solidified shell 3b, and is not present between the roll surface and the molten metal 3.
従って、ロール面での凝固速度を均一にスルコトができ
、鋳片での割れの発生を防止し得る。Therefore, the solidification rate on the roll surface can be made uniform, and cracks can be prevented from occurring in the slab.
第1図に示したところに従い、厚さ2閣、輻600 w
mの薄鋳片を、第1表に示す各種溶鋼から連続鋳造する
に当たり、第1表に示す組成になる雰囲気ガスで密閉蓋
5内を充満した後、さらにノズル7a〜7dから鋳片1
1I2当たり1ON以上の流量で雰囲気ガスを供給した
。得られた鋳片の表面性状について調べた結果を第1表
に示す。As shown in Figure 1, the thickness is 2 mm and the diameter is 600 w.
In order to continuously cast thin slabs of m in thickness from various types of molten steel shown in Table 1, after filling the airtight lid 5 with an atmospheric gas having the composition shown in Table 1, the slabs 1 are further cast from nozzles 7a to 7d.
Atmospheric gas was supplied at a flow rate of 1ON or more per 1I2. Table 1 shows the results of investigating the surface properties of the obtained slabs.
また、比較として、同様の連続鋳造を不活性ガス雰囲気
下で行った場合についても、得られた鋳片の表面性状を
調べた。その結果を第1表に併記する。For comparison, the surface properties of the slabs obtained were also investigated when similar continuous casting was performed under an inert gas atmosphere. The results are also listed in Table 1.
第1表
〔発明の効果〕
この発明によれば、割れ、ひび割れ、および不均一な凹
凸等、従来の双ロール式連続鋳造において不可避であっ
た表面欠陥のない、優れた表面性状の薄鋳片を製造する
ことができ、従前のスラブから熱間圧延を経て得られる
熱延材と何ら遜色のない薄鋳片を提供し得る。Table 1 [Effects of the Invention] According to the present invention, a thin slab with excellent surface quality is free from surface defects such as cracks, cracks, and non-uniform irregularities that are inevitable in conventional twin-roll continuous casting. It is possible to produce thin slabs that are comparable to hot-rolled materials obtained from conventional slabs through hot rolling.
第1図は、この発明に使用する双ロール式連続鋳造機を
示す模式図、
第2図は、雰囲気ガス供給用のノズルを示す斜視図、
第3図は、別の双ロール式連続鋳造機を示す模式図、
第4図および第5図は、鋳造中の雰囲気ガスの挙動を示
す模式図である。
la、 lb・・・冷却ロール、 2・・・供給ノズル
、3・・・溶融金属、3a・・・湯溜り部、3b・・・
凝固シェル、4・・・薄鋳片、5・・・密閉蓋、6・・
・供給管、7a〜7d・・・ノズル、8a・・・パイプ
、8b・・・スリット。
第1図
第5図
第4図Fig. 1 is a schematic diagram showing a twin-roll continuous casting machine used in the present invention, Fig. 2 is a perspective view showing a nozzle for supplying atmospheric gas, and Fig. 3 is another twin-roll continuous casting machine. FIGS. 4 and 5 are schematic diagrams showing the behavior of atmospheric gas during casting. la, lb... cooling roll, 2... supply nozzle, 3... molten metal, 3a... sump, 3b...
Solidified shell, 4... Thin slab, 5... Airtight lid, 6...
- Supply pipe, 7a to 7d... nozzle, 8a... pipe, 8b... slit. Figure 1 Figure 5 Figure 4
Claims (1)
溶融金属を供給し、その冷却ロール面上で連続的に急冷
凝固させて薄鋳片を製造するに当たり、 上記冷却ロール対およびこれらのロール間に供給した溶
融金属の表面に対し、吸収性ガスの含有率が60vol
%以上の雰囲気ガスを供給することを特徴とする薄鋳片
の連続鋳造方法。[Claims] 1. In manufacturing a thin slab by supplying molten metal to a pool between a pair of cooling rolls that rotate opposite each other and continuously rapidly solidifying it on the surface of the cooling roll. , the absorbent gas content is 60 vol with respect to the surface of the cooling roll pair and the molten metal supplied between these rolls.
A continuous casting method for thin slabs, characterized by supplying an atmospheric gas of % or more.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP31591290A JPH04187346A (en) | 1990-11-22 | 1990-11-22 | Method for continuously casting thin cast strip |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP31591290A JPH04187346A (en) | 1990-11-22 | 1990-11-22 | Method for continuously casting thin cast strip |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH04187346A true JPH04187346A (en) | 1992-07-06 |
Family
ID=18071105
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP31591290A Pending JPH04187346A (en) | 1990-11-22 | 1990-11-22 | Method for continuously casting thin cast strip |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH04187346A (en) |
-
1990
- 1990-11-22 JP JP31591290A patent/JPH04187346A/en active Pending
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