JP2000178636A - Production of clean steel in rh vacuum-degassing apparatus - Google Patents
Production of clean steel in rh vacuum-degassing apparatusInfo
- Publication number
- JP2000178636A JP2000178636A JP10350831A JP35083198A JP2000178636A JP 2000178636 A JP2000178636 A JP 2000178636A JP 10350831 A JP10350831 A JP 10350831A JP 35083198 A JP35083198 A JP 35083198A JP 2000178636 A JP2000178636 A JP 2000178636A
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- JP
- Japan
- Prior art keywords
- vacuum
- molten steel
- gas
- porous brick
- blown
- 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.)
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- Treatment Of Steel In Its Molten State (AREA)
- Furnace Details (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ＲＨ真空脱ガス装
置を用いて、酸化物系非金属介在物の少ない清浄鋼を安
定して製造する方法に関するものである。[0001] The present invention relates to a method for stably producing clean steel containing few oxide-based nonmetallic inclusions by using an RH vacuum degassing apparatus.
【０００２】[0002]
【従来の技術】近年の鉄鋼材料の高機能化及び高品質化
への要求の高まりから、燐、硫黄等の不純物元素や、脱
酸生成物、転炉スラグ及びモールドパウダー等を起源と
する酸化物系非金属介在物（以下、「介在物」と記す）
を極力低減することが要望されている。この内、介在物
は薄鋼板製品での表面欠陥の主原因となるため、精錬か
ら鋳造に至るまで、その低減対策が検討され、その結
果、介在物を低減するためには、溶鋼攪拌による介在物
の凝集・合体と、溶鋼中に吹き込まれたガス気泡への介
在物の吸着とが、特に効果があることが挙げられるに至
り、清浄鋼を製造する手段として、ＲＨ真空脱ガス装置
を用いて溶鋼に大量の不活性ガスを吹き込み、溶鋼を攪
拌して介在物を除去する方法が多数提案されてきた。2. Description of the Related Art In recent years, demands for higher functionality and higher quality of steel materials have increased, and oxidation elements originating from impurity elements such as phosphorus and sulfur, deoxidation products, converter slag, mold powder, and the like have been developed. Nonmetallic inclusions (hereinafter referred to as "inclusions")
It is desired to reduce as much as possible. Of these, inclusions are the main cause of surface defects in thin steel products, and measures to reduce inclusions from refining to casting are being studied. The agglomeration and coalescence of substances and the adsorption of inclusions to gas bubbles blown into the molten steel have been particularly effective. As a means for producing clean steel, an RH vacuum degassing device was used. Many methods have been proposed for blowing a large amount of inert gas into molten steel and stirring the molten steel to remove inclusions.
【０００３】例えば、特開昭５７−２００５１４号公報
には、ＲＨ真空脱ガス装置の上昇側浸漬管に環流ガスを
吹き込むと共に、上昇側浸漬管直下の取鍋底からもＡｒ
ガスを吹き込み、取鍋底から吹き込むＡｒガスにて、取
鍋内溶鋼の攪拌強化と真空槽を環流する溶鋼量の増大化
を図り、介在物の低減を向上させた方法が開示され、
又、特開平６−８８１１９号公報には、ＲＨ真空脱ガス
装置の真空槽の内面底部にガス吹き込み煉瓦を２箇所以
上配置し、溶鋼中へ不活性ガスを吹き込みながら精錬す
る方法が開示されている。[0003] For example, Japanese Patent Application Laid-Open No. 57-200514 discloses that reflux gas is blown into a rising side immersion pipe of an RH vacuum degassing apparatus, and Ar gas is also supplied from the bottom of a ladle directly below the rising side immersion pipe.
A method in which gas is blown and Ar gas blown from the bottom of the ladle is used to enhance the stirring of the molten steel in the ladle and increase the amount of molten steel circulating in the vacuum tank, thereby improving the reduction of inclusions, is disclosed.
Japanese Patent Application Laid-Open No. 6-88119 discloses a method in which two or more gas-injecting bricks are arranged at the bottom of the inner surface of a vacuum chamber of an RH vacuum degassing apparatus, and refining is performed while blowing an inert gas into molten steel. I have.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記特
開昭５７−２００５１４号公報に開示された方法では、
ガス気泡は合体して気泡界面積が小さくなるため、介在
物のガス気泡への吸着は少なく、又、浸漬管に余りに大
量の不活性ガスを吹き込むと、ガスの吹き抜けが起こ
り、溶鋼の環流及び攪拌が阻害され、介在物を効果的に
低減することができない。However, according to the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 57-200514,
Since gas bubbles coalesce and the bubble boundary area becomes smaller, the adsorption of inclusions to the gas bubbles is small, and if too much inert gas is blown into the immersion tube, gas blow-through will occur, causing the molten steel to circulate and recirculate. Stirring is hindered and inclusions cannot be reduced effectively.
【０００５】上記特開平６−８８１１９号公報に開示さ
れた方法では、複数個のガス吹き込み煉瓦を設置してい
るにも関わらず、互いに離れた位置に設置しているの
で、ガスを吹き込んでいない位置を流れる溶鋼中介在物
のガス気泡への吸着は望めず、微細な介在物の除去が効
率的に行われない。このように、従来の方法では、清浄
性の高い鋼を安定して製造するまでには至っていない。In the method disclosed in Japanese Patent Application Laid-Open No. Hei 6-88119, gas is not injected because the bricks are installed at positions apart from each other, even though a plurality of gas injection bricks are installed. Adsorption of the inclusions in the molten steel flowing through the position to the gas bubbles cannot be expected, and the removal of fine inclusions is not performed efficiently. As described above, the conventional method has not been able to stably produce highly clean steel.
【０００６】本発明は上記事情に鑑みなされたもので、
その目的とするところは、介在物の少ない清浄鋼を、Ｒ
Ｈ真空脱ガス装置を用いて、安定して製造する方法を提
供することである。The present invention has been made in view of the above circumstances,
The aim is to use clean steel with few inclusions,
It is an object of the present invention to provide a method for stably producing a product using an H vacuum degassing device.
【０００７】[0007]
【課題を解決するための手段】本発明によるＲＨ真空脱
ガス装置における清浄鋼の製造方法は、真空槽内面底部
の、上昇側浸漬管の中心と下降側浸漬管の中心とを結ぶ
直線を横切る位置に、真空槽内壁直径の１／２以上の長
さに渡って多孔質煉瓦を設置し、上昇側浸漬管から環流
用Ａｒガスを吹き込んで取鍋と真空槽との間で溶鋼を環
流させるＲＨ真空脱ガス精錬の際に、前記多孔質煉瓦か
ら不活性ガスを吹き込むことを特徴とするものである。
その際に、多孔質煉瓦を、真空槽の一方の内壁から対向
する他方の内壁までの全範囲に渡って設置し、不活性ガ
スを吹き込むことが好ましい。According to the present invention, there is provided a method for producing clean steel in an RH vacuum degassing apparatus, comprising the steps of: forming a straight line connecting the center of an ascending immersion pipe and the center of a descending immersion pipe at the bottom of the inner surface of a vacuum chamber; At the crossing position, a porous brick is installed over a length equal to or more than の of the inner diameter of the vacuum tank, and Ar gas for reflux is blown from the rising dip tube to circulate molten steel between the ladle and the vacuum tank. An inert gas is blown from the porous brick during the RH vacuum degassing refining to be performed.
At that time, it is preferable to install the porous bricks over the entire range from one inner wall of the vacuum chamber to the other opposing inner wall, and to blow in an inert gas.
【０００８】本発明では多孔質煉瓦を用いてＡｒガス等
の不活性ガスを溶鋼中に吹き込む。多孔質煉瓦から吹き
込むことで、吹き込まれる気泡は微細になり、溶鋼に接
触する機会が増え、介在物の気泡への吸着を促進させる
ことができる。更に、上昇側浸漬管と下降側浸漬管の中
心同士を結ぶ直線を横切る位置に、真空槽内壁直径の１
／２以上の長さに渡って多孔質煉瓦を設置するので、取
鍋と真空槽との間を環流する溶鋼の大部分に不活性ガス
が吹き込まれることになり、溶鋼中の介在物と微細なガ
ス気泡との接触機会が一層増大し、介在物の気泡への吸
着が促進され、溶鋼の清浄性が向上する。特に、多孔質
煉瓦を真空槽の一方の内壁から対向する他方の内壁まで
の全範囲に渡って設置することで、環流する溶鋼の全て
に微細なガス気泡が吹き込まれることになり、清浄性が
より一層向上する。In the present invention, an inert gas such as Ar gas is blown into molten steel using a porous brick. By blowing from the porous brick, the blown bubbles become fine, the chance of contact with the molten steel increases, and adsorption of inclusions to the bubbles can be promoted. Further, at a position crossing a straight line connecting the centers of the ascending-side immersion pipe and the descending-side immersion pipe, the diameter of the inner wall of the vacuum chamber is 1 mm.
Since the porous brick is installed over a length of / 2 or more, the inert gas is blown into most of the molten steel circulating between the ladle and the vacuum tank, and the inclusions in the molten steel and fine particles The chance of contact with the gas bubbles further increases, the adsorption of inclusions to the bubbles is promoted, and the cleanliness of the molten steel is improved. In particular, by installing the porous brick over the entire range from one inner wall of the vacuum tank to the other opposing inner wall, fine gas bubbles are blown into all of the molten steel that flows, and cleanliness is improved. Even better.
【０００９】その際に、多孔質煉瓦を設置する範囲が真
空槽内壁直径の１／２未満では、ガスを吹き込んでいな
い部分を流れる溶鋼が増え、介在物のガス気泡への吸着
が低減して、清浄性の高い溶鋼を安定して得ることがで
きない。[0009] At this time, if the area where the porous brick is installed is less than 1/2 of the inner diameter of the vacuum chamber, the amount of molten steel flowing in the portion where gas is not blown increases, and adsorption of inclusions to gas bubbles is reduced. However, it is not possible to stably obtain a highly clean molten steel.
【００１０】[0010]
【発明の実施の形態】以下、本発明を図面に基づき説明
する。図１は、本発明を実施したＲＨ真空脱ガス装置の
縦断面概略図であり、図２は、図１におけるＸ−Ｘ断面
の概略図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of an RH vacuum degassing apparatus embodying the present invention, and FIG. 2 is a schematic sectional view taken along line XX in FIG.
【００１１】これらの図において、内壁直径がＤである
上部槽６及び下部槽７からなる真空槽５と、下部槽７の
下部に設けた上昇側浸漬管８及び下降側浸漬管９とで、
ＲＨ真空脱ガス装置１の基部が構成されており、上部槽
６には、原料投入口１２と、排気装置（図示せず）と接
続するダクト１３とが設けられ、又、上昇側浸漬管８に
はＡｒガス吹き込み管１０が設けられ、Ａｒガス吹き込
み管１０からは環流用Ａｒガスが上昇側浸漬管８内に吹
き込まれる構造となっている。In these figures, a vacuum tank 5 composed of an upper tank 6 and a lower tank 7 having an inner wall diameter of D, and an ascending-side immersion pipe 8 and a descending-side immersion pipe 9 provided below the lower tank 7 are:
The base of the RH vacuum degassing device 1 is configured. The upper tank 6 is provided with a raw material inlet 12 and a duct 13 connected to an exhaust device (not shown). Is provided with an Ar gas injection pipe 10 from which Ar gas for reflux is blown into the rising side immersion pipe 8.
【００１２】そして、下部槽７の内面底部の、上昇側浸
漬管８の中心と下降側浸漬管９の中心とを結ぶ直線をほ
ぼ直角に横切る位置に、下部槽７の一方の内壁から対向
する他方の内壁に渡って多孔質煉瓦１１が設置されてい
る。尚、図２では、多孔質煉瓦１１が下部槽７の一方の
内壁から対向する他方の内壁に渡って設置されている
が、本発明では、このように全範囲に渡って多孔質煉瓦
１１を設置する必要はなく、下部槽７の内壁直径（Ｄ）
の１／２以上の長さに渡って設置すれば良い。又、図２
では、下部槽７の中心を通る位置に多孔質煉瓦１１が設
置されているが、必ずしも下部槽７の中心を通る位置に
設置する必要はない。但し、ガス気泡に接触する溶鋼量
を増加させるために、上昇側浸漬管８の中心と下降側浸
漬管９の中心とを結ぶ直線を直角に横切るように設置す
ることが好ましい。多孔質煉瓦１１は慣用のアルミナ質
やマグネシア質等とする。[0012] One inner wall of the lower tank 7 is opposed to the bottom of the inner surface of the lower tank 7 at a position substantially perpendicular to a straight line connecting the center of the rising immersion pipe 8 and the center of the descending immersion pipe 9. A porous brick 11 is provided over the other inner wall. In FIG. 2, the porous brick 11 is installed from one inner wall of the lower tank 7 to the other opposing inner wall. However, in the present invention, the porous brick 11 is It is not necessary to install, the inner wall diameter of lower tank 7 (D)
It may be installed over a half or more of the length. Also, FIG.
In the embodiment, the porous brick 11 is installed at a position passing through the center of the lower tank 7, but it is not always necessary to install the porous brick 11 at a position passing through the center of the lower tank 7. However, in order to increase the amount of molten steel that comes into contact with gas bubbles, it is preferable that the steel sheet is installed so as to cross a straight line connecting the center of the ascending pipe 8 and the center of the descending pipe 9 at right angles. The porous brick 11 is made of conventional alumina, magnesia or the like.
【００１３】このような構成のＲＨ真空脱ガス装置１に
おける本発明の適用方法を以下に説明する。先ず、転炉
や電気炉等で精錬して溶鋼３を得、こうして得た溶鋼３
を収納する取鍋２を真空槽５の直下に搬入する。取鍋２
内には転炉及び電気炉精錬時のスラグ４が一部混入し、
溶鋼３の湯面を覆っている。An application method of the present invention in the RH vacuum degassing apparatus 1 having such a configuration will be described below. First, the molten steel 3 is refined in a converter or an electric furnace to obtain the molten steel 3.
The ladle 2 for storing is placed directly below the vacuum tank 5. Ladle 2
Inside the slag 4 from the converter and electric furnace refining is partially mixed,
It covers the surface of molten steel 3.
【００１４】尚、スラグ４は、ＦｅＯやＭｎＯ等の低級
酸化物を含み、これら低級酸化物は溶鋼３中のＡｌと反
応して、アルミナを新たに生成させ、溶鋼３の清浄性を
劣化させる。そのため、取鍋２内のスラグ４に金属Ａｌ
又はＣａＯを主成分とするスラグ改質剤等を添加し、予
めスラグ４中のＦｅＯやＭｎＯ等の低級酸化物を還元し
ておくことが好ましい。The slag 4 contains lower oxides such as FeO and MnO. These lower oxides react with Al in the molten steel 3 to newly generate alumina and deteriorate the cleanliness of the molten steel 3. . Therefore, the metal Al is added to the slag 4 in the ladle 2.
Alternatively, it is preferable to add a slag modifier containing CaO as a main component or the like to reduce a lower oxide such as FeO or MnO in the slag 4 in advance.
【００１５】次いで、昇降装置（図示せず）にて取鍋２
を上昇させ、上昇側浸漬管８及び下降側浸漬管９を取鍋
２内の溶鋼３に浸漬させる。そして、Ａｒガス吹き込み
管１０から上昇側浸漬管８内にＡｒガスを吹き込むと共
に、真空槽５内を排気装置にて排気して真空槽５内を減
圧する。真空槽５内が減圧されると、取鍋２内の溶鋼３
は、Ａｒガス吹き込み管１０から吹き込まれるＡｒガス
と共に上昇側浸漬管８を上昇して真空槽５内に流入し、
その後、下降側浸漬管９を介して取鍋２に戻る流れ、所
謂、環流を形成してＲＨ真空脱ガス精錬が施される。Next, the ladle 2 is moved by a lifting device (not shown).
Is raised, and the ascending-side immersion pipe 8 and the descending-side immersion pipe 9 are immersed in the molten steel 3 in the ladle 2. Then, Ar gas is blown into the rising side immersion pipe 8 from the Ar gas blowing pipe 10 and the inside of the vacuum tank 5 is evacuated by an exhaust device to reduce the pressure in the vacuum tank 5. When the pressure in the vacuum chamber 5 is reduced, the molten steel 3 in the ladle 2
Rises along the rising dipping tube 8 together with the Ar gas blown from the Ar gas blowing tube 10 and flows into the vacuum chamber 5,
Thereafter, a flow returning to the ladle 2 via the descending dipping pipe 9, that is, a so-called reflux is formed, and RH vacuum degassing refining is performed.
【００１６】処理する鋼種の用途に従い、脱水素、脱炭
等の処理を施し、次いで、原料投入口１２から真空槽５
内の溶鋼３にＡｌを添加して脱酸し、更に、必要により
Ｃ、Ｓｉ、Ｍｎ等の成分を調整する。添加するＡｌは金
属ＡｌやＡｌ合金等を使用し、Ａｌ添加量は、脱酸後の
溶鋼３中に０．０１ｗｔ％以上のＡｌが残留する程度と
する。尚、Ａｌ脱酸の時期はＲＨ真空脱ガス精錬中に限
るものではなく、取鍋２への受鋼直後でも、又、受鋼直
後とＲＨ真空脱ガス精錬中との２回以上に分けてＡｌを
添加しても良い。According to the use of the type of steel to be treated, treatment such as dehydrogenation and decarburization is performed.
Al is added to the molten steel 3 in the inside to deoxidize, and components such as C, Si, and Mn are adjusted if necessary. Al added is metal Al, an Al alloy, or the like, and the amount of Al added is such that 0.01 wt% or more of Al remains in the molten steel 3 after deoxidation. The time of Al deoxidation is not limited to the time during RH vacuum degassing and refining, and is divided into two or more times immediately after receiving steel in the ladle 2 and immediately after steel receiving and during RH vacuum degassing and refining. Al may be added.
【００１７】溶鋼３がＡｌ脱酸されてから少なくても２
分間以上、好ましくは６分間以上多孔質煉瓦１１から溶
鋼３中にＡｒガス等の不活性ガスを吹き込む。２分間未
満では、Ａｌ脱酸で生成した介在物のガス気泡への吸着
量が不足して、安定して清浄性の高い溶鋼３を得ること
ができないからである。又、不活性ガスの吹き込み量
は、ＲＨ真空脱ガス装置１の容量にもよるが、通常５０
０Ｎｌ／ｍｉｎ以上であれば、本発明の目的を達成する
ことができる。At least 2 after molten steel 3 has been deoxidized with Al
An inert gas such as Ar gas is blown into the molten steel 3 from the porous brick 11 for at least 6 minutes, preferably at least 6 minutes. If the duration is less than 2 minutes, the amount of inclusions generated by Al deoxidation on the gas bubbles is insufficient, so that the molten steel 3 having high cleanliness cannot be obtained stably. The amount of the inert gas to be blown depends on the capacity of the RH vacuum degassing apparatus 1, but usually 50
If it is 0 Nl / min or more, the object of the present invention can be achieved.
【００１８】Ａｌ脱酸後の真空槽５内の圧力は５ｔｏｒ
ｒ以下に維持することが好ましい。真空槽５内の圧力が
５ｔｏｒｒを超えると、溶鋼３の環流量が低下して介在
物の浮上・分離が妨げられるからである。又、多孔質煉
瓦１１からの不活性ガスの吹き込みは、溶鋼３のＡｌ脱
酸後から所定時間行っても、又、ＲＨ真空脱ガス精錬の
開始から終了まで行っても、どちらでも良い。The pressure in the vacuum chamber 5 after Al deoxidation is 5 torr.
It is preferable to maintain r or less. If the pressure in the vacuum chamber 5 exceeds 5 torr, the ring flow rate of the molten steel 3 decreases, and the floating and separation of inclusions is hindered. The blowing of the inert gas from the porous brick 11 may be performed for a predetermined time after the Al deoxidation of the molten steel 3 or may be performed from the start to the end of the RH vacuum degas refining.
【００１９】そして、多孔質煉瓦１１から所定時間不活
性ガスを吹き込んだ後、真空槽５内を大気圧に戻してＲ
Ｈ真空脱ガス精錬を終了し、次工程の連続鋳造設備や普
通造塊設備等の鋳造設備に取鍋２を搬出して溶鋼３を鋳
造する。After blowing an inert gas from the porous brick 11 for a predetermined time, the inside of the vacuum chamber 5 is returned to the atmospheric pressure, and R
After the H vacuum degassing refining is finished, the ladle 2 is carried out to a casting facility such as a continuous casting facility or a normal ingot making facility in the next step, and the molten steel 3 is cast.
【００２０】このようにしてＲＨ真空脱ガス精錬を行う
ことで、溶鋼中の介在物は効率良く不活性ガス気泡に吸
着され、介在物の少ない清浄鋼を安定して製造すること
ができる。By performing the RH vacuum degassing refining in this way, inclusions in the molten steel are efficiently adsorbed by the inert gas bubbles, and a clean steel with few inclusions can be stably manufactured.
【００２１】[0021]
【実施例】図１に示すＲＨ真空脱ガス装置を用いて本発
明を実施した例を以下に説明する。対象とした溶鋼は、
高炉から出銑された溶銑を転炉精錬して取鍋に出鋼した
もので、溶鋼の炭素濃度は０．０４ｗｔ％、転炉からの
出鋼量は２５０トンであり、未脱酸の状態でＲＨ真空脱
ガス装置に搬送した。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is implemented using the RH vacuum degassing apparatus shown in FIG. 1 will be described below. The target molten steel is
The molten iron from the blast furnace was refined in a converter and was tapped into a ladle. The carbon concentration of the molten steel was 0.04 wt%, the tapping amount from the converter was 250 tons, and was not deoxidized. At RH vacuum degassing apparatus.
【００２２】取鍋内スラグの組成はＣａＯ−ＳｉＯ2 −
Ａｌ2 Ｏ3 −ＭｇＯ系であり、出鋼後ＣａＯを主成分と
するスラグ改質剤を取鍋内に添加して、スラグのＴ．Ｆ
ｅとＭｎＯの合計濃度を４ｗｔ％以下とした。尚、Ｔ．
Ｆｅとは、スラグ中の全ての鉄酸化物（ＦｅＯやＦｅ2
Ｏ3 等）の鉄分の合計値である。The composition of the slag in the ladle is CaO--SiO 2-
An Al 2 O 3 —MgO-based slag modifier containing CaO as a main component after tapping is added into the ladle to reduce the T.V. F
The total concentration of e and MnO was set to 4 wt% or less. In addition, T.
Fe means all iron oxides (FeO and Fe 2
O 3 etc.).
【００２３】環流用Ａｒガス流量を３０００Ｎｌ／ｍｉ
ｎ、真空槽内の圧力を０．５〜２ｔｏｒｒまで減圧して
所定時間真空脱炭精錬を行った後、溶鋼中の溶解酸素濃
度を酸素プローブにて測定し、溶解酸素濃度に基づいて
算出した所定量の金属Ａｌを原料投入口から添加して溶
鋼中Ａｌ濃度を０．０３ｗｔ％に調整した。そして、金
属Ａｌの添加直後から、溶鋼を環流させつつ多孔質煉瓦
から１０００Ｎｌ／ｍｉｎでＡｒガスを吹き込み、１０
分間吹き込んだ後、ＲＨ真空脱ガス精錬を終了した。そ
の際に、金属ＡｌによるＡｌ脱酸直後と、Ａｌ脱酸後１
０分経過時に溶鋼からサンプルを採取し、サンプル中の
アルミナ介在物の大きさ別の個数を調査した。The Ar gas flow rate for circulation is 3000 Nl / mi.
n, after reducing the pressure in the vacuum chamber to 0.5 to 2 torr and performing vacuum decarburization refining for a predetermined time, the dissolved oxygen concentration in the molten steel was measured with an oxygen probe, and calculated based on the dissolved oxygen concentration. A predetermined amount of metal Al was added from a raw material inlet to adjust the Al concentration in molten steel to 0.03 wt%. Immediately after the addition of metal Al, Ar gas was blown from the porous brick at 1000 Nl / min while the molten steel was refluxed.
After blowing for minutes, the RH vacuum degassing refining was terminated. At this time, immediately after Al deoxidation by the metal Al and 1 after Al deoxidation.
A sample was taken from the molten steel at the time of 0 minutes, and the number of alumina inclusions in the sample by size was examined.
【００２４】又、比較のために、金属Ａｌによる脱酸ま
では上記と同一の製造方法で処理し、Ａｌ脱酸後に環流
用Ａｒガス量を４０００Ｎｌ／ｍｉｎとして１０分間環
流させた比較例も実施した。比較例においてもＡｌ脱酸
直後とＡｌ脱酸後１０分経過時に溶鋼からサンプルを採
取し、アルミナ介在物の大きさ別の個数を調査した。For comparison, a comparative example was also carried out in which the treatment was carried out in the same manner as described above up to the deoxidation with metallic Al, and after the deoxidation of Al, the gas was refluxed for 10 minutes at an argon gas flow rate of 4000 Nl / min. did. Also in the comparative example, samples were taken from the molten steel immediately after Al deoxidation and 10 minutes after Al deoxidation, and the number of alumina inclusions by size was investigated.
【００２５】図３は、このようにして調査した実施例及
び比較例におけるアルミナ介在物の大きさ別の個数を示
す図である。図３に示すように、Ａｌ脱酸から１０分後
の溶鋼中アルミナ介在物個数は、調査した全てのアルミ
ナ粒径において、本発明の実施例の方が少なくなってい
た。このことから、本発明による処理を施すことによ
り、単に上昇側浸漬管から同量のＡｒガスを吹き込む場
合よりも、鋼中介在物を低減することが可能であること
が分かった。尚、図３には、比較例におけるＡｌ脱酸直
後の調査結果が記載されていないが、実施例のＡｌ脱酸
直後の結果とほぼ同一であったので省略し、実施例のデ
ータで代用した。FIG. 3 is a diagram showing the number of alumina inclusions by size in the examples and comparative examples investigated in this way. As shown in FIG. 3, the number of alumina inclusions in the molten steel 10 minutes after Al deoxidation was smaller in the example of the present invention in all the alumina particle sizes examined. From this, it has been found that by performing the treatment according to the present invention, it is possible to reduce the inclusions in the steel as compared with the case where the same amount of Ar gas is simply blown from the ascending dip tube. Note that FIG. 3 does not show the result of the investigation immediately after Al deoxidation in the comparative example, but was omitted because it was almost the same as the result immediately after Al deoxidation in the example, and was substituted by the data of the example. .
【００２６】[0026]
【発明の効果】本発明では、真空槽内面底部の、上昇側
浸漬管の中心と下降側浸漬管の中心とを結ぶ直線を横切
る位置に、真空槽内壁直径の１／２以上の長さに渡って
多孔質煉瓦を設置して不活性ガスを吹き込むので、溶鋼
中の介在物はガス気泡に効率良く吸着し、介在物の極め
て少ない清浄鋼を安定して製造することができる。According to the present invention, at least a half of the inner diameter of the vacuum chamber wall is located at the bottom of the inner surface of the vacuum chamber at a position crossing a straight line connecting the center of the ascending pipe and the center of the descending pipe. Therefore, the inclusions in the molten steel are efficiently adsorbed by the gas bubbles, and the clean steel having extremely few inclusions can be stably manufactured.
【図１】本発明を実施したＲＨ真空脱ガス装置の縦断面
概略図である。FIG. 1 is a schematic longitudinal sectional view of an RH vacuum degassing apparatus embodying the present invention.
【図２】図１におけるＸ−Ｘ断面の概略図である。FIG. 2 is a schematic view of a section taken along line XX in FIG.
【図３】アルミナの大きさ別の個数を実施例と比較例と
で比較して示した図である。FIG. 3 is a diagram showing the number of alumina according to the size in comparison between an example and a comparative example.
１ ＲＨ真空脱ガス装置 ２ 取鍋 ３ 溶鋼 ４ スラグ ５ 真空槽 ６ 上部槽 ７ 下部槽 ８ 上昇側浸漬管 ９ 下降側浸漬管 １０ Ａｒガス吹き込み管 １１ 多孔質煉瓦 １２ 原料投入口 １３ ダクト DESCRIPTION OF SYMBOLS 1 RH vacuum degassing apparatus 2 Ladle 3 Molten steel 4 Slag 5 Vacuum tank 6 Upper tank 7 Lower tank 8 Ascending side immersion pipe 9 Descending side immersion pipe 10 Ar gas injection pipe 11 Porous brick 12 Material inlet 13 Duct
───────────────────────────────────────────────────── フロントページの続き (72)発明者 櫻井 栄司 東京都千代田区丸の内一丁目１番２号 日 本鋼管株式会社内 Ｆターム(参考） 4K013 BA08 BA09 CE01 CE05 4K063 AA03 AA16 BA02 CA03 DA19 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Eiji Sakurai 1-2-1 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 4K013 BA08 BA09 CE01 CE05 4K063 AA03 AA16 BA02 CA03 DA19
Claims (2)
と下降側浸漬管の中心とを結ぶ直線を横切る位置に、真
空槽内壁直径の１／２以上の長さに渡って多孔質煉瓦を
設置し、上昇側浸漬管から環流用Ａｒガスを吹き込んで
取鍋と真空槽との間で溶鋼を環流させるＲＨ真空脱ガス
精錬の際に、前記多孔質煉瓦から不活性ガスを吹き込む
ことを特徴とするＲＨ真空脱ガス装置における清浄鋼の
製造方法。At least one half of the inner diameter of the vacuum chamber is pierced at the bottom of the inner surface of the vacuum chamber at a position crossing a straight line connecting the center of the ascending pipe and the center of the descending pipe. An inert gas is blown from the porous brick during RH vacuum degassing refining in which a porous brick is installed and Ar gas for reflux is blown from a rising dip pipe to reflux molten steel between a ladle and a vacuum tank. A method for producing clean steel in an RH vacuum degassing apparatus.
から対向する内壁までの全範囲に渡って設置したことを
特徴とする請求項１に記載のＲＨ真空脱ガス装置におけ
る清浄鋼の製造方法。2. The RH vacuum degassing apparatus according to claim 1, wherein the porous brick is installed over an entire range from one inner wall of the vacuum chamber to an opposing inner wall. Production method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10350831A JP2000178636A (en) | 1998-12-10 | 1998-12-10 | Production of clean steel in rh vacuum-degassing apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10350831A JP2000178636A (en) | 1998-12-10 | 1998-12-10 | Production of clean steel in rh vacuum-degassing apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2000178636A true JP2000178636A (en) | 2000-06-27 |
Family
ID=18413190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10350831A Pending JP2000178636A (en) | 1998-12-10 | 1998-12-10 | Production of clean steel in rh vacuum-degassing apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2000178636A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103866089A (en) * | 2012-12-12 | 2014-06-18 | 中冶宝钢技术服务有限公司 | Vacuum tank alloy feed inlet pre-constructing technology |
| CN110982991A (en) * | 2019-12-25 | 2020-04-10 | 芜湖新兴铸管有限责任公司 | Equipment for controlling defects of slag channel and air hole on surface of round billet |
-
1998
- 1998-12-10 JP JP10350831A patent/JP2000178636A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103866089A (en) * | 2012-12-12 | 2014-06-18 | 中冶宝钢技术服务有限公司 | Vacuum tank alloy feed inlet pre-constructing technology |
| CN110982991A (en) * | 2019-12-25 | 2020-04-10 | 芜湖新兴铸管有限责任公司 | Equipment for controlling defects of slag channel and air hole on surface of round billet |
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