EP0222321B1 - Procédé pour éviter des explosions de moules pendant la coulée continue d'aciers de décolletages - Google Patents

Procédé pour éviter des explosions de moules pendant la coulée continue d'aciers de décolletages Download PDF

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Publication number
EP0222321B1
EP0222321B1 EP86115363A EP86115363A EP0222321B1 EP 0222321 B1 EP0222321 B1 EP 0222321B1 EP 86115363 A EP86115363 A EP 86115363A EP 86115363 A EP86115363 A EP 86115363A EP 0222321 B1 EP0222321 B1 EP 0222321B1
Authority
EP
European Patent Office
Prior art keywords
mold
lubricant
molten steel
recited
continuous casting
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 - Lifetime
Application number
EP86115363A
Other languages
German (de)
English (en)
Other versions
EP0222321A2 (fr
EP0222321A3 (en
Inventor
Howard M. Pielet
Debanshu Bhattacharya
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Inland Steel Co
Original Assignee
Inland Steel Co
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Filing date
Publication date
Application filed by Inland Steel Co filed Critical Inland Steel Co
Publication of EP0222321A2 publication Critical patent/EP0222321A2/fr
Publication of EP0222321A3 publication Critical patent/EP0222321A3/en
Application granted granted Critical
Publication of EP0222321B1 publication Critical patent/EP0222321B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/07—Lubricating the moulds

Definitions

  • the present invention relates generally to the continuous casting of free-machining steels and more particularly to a method for preventing mold explosions during the continuous casting of molten steel containing at least one of lead and bismuth.
  • molten steel is flowed from a ladle into a intermediate container called a tundish having a plurality of spigots in its bottom through which molten steel is flowed into a casting mold having an open upstream end and sidewalls extending from the upstream end to a downstream end initially closed by a so-called "dummy bar".
  • the sidewalls of the mold are cooled, e.g. with a water jacket, and the molten steel initially contacting the dummy bar and the side-walls solidifies to form a solid shell enclosing unsolidified molten steel.
  • the dummy bar is withdrawn from the mold's downstream end, and the solidified shell containing unsolidified molten steel advances through the mold in a downstream direction, e.g. under the urging of gravity.
  • the portion of the mold vacated by the shell's downstream movement is replenished with additional molten steel.
  • a lubricant is employed.
  • the lubricant is typically an organic compound such as a petroleum-base oil, and the lubricant is typically applied to the interior surface of the mold before the casting operation begins. Lubricants are also injected between the molten steel and the interior surface of the mold walls during the casting operation. Typical examples of lubricants employed during the continuous casting of molten steel are set forth in Borg, et al U.S. Patent No. 4120344.
  • GB-A 2 027 375 discloses the operation of a continuous casting mold for the continuous casting of molten steel, wherein said molten steel is introduced into a continuous casting mold having an interior surface, said molten steel is at least partially solidified in said mold to form a solid shell, and said interior surface is lubricated with a non-metallic, non-organic mold lubricant to prevent the sticking of said shell to said interior surface during the cast.
  • the continuous casting mold is horizontally disposed and the lubricant is a relatively permanent electroplated coating of nickel or chromium in which is disposed a solid non-organic lubricant material and the metal being cast does not contain bismuth and lead in machinability increasing amounts.
  • Engeler U.S. Patent No. 4 165 780 discloses a method for preventing mold explosions in the continuous casting of molten steel containing lead according to the preamble to Claim 1.
  • Engeler teaches that mold explosions can be avoided by eliminating the use of oil as a mold lubricant and by employing, as the mold lubricant, a mixture of a liquid inert gas (e.g. nitrogen) and a flux powder (e.g. carbon particles) applied atop the molten steel in the mold while at the same time oscillating the mold back and forth along the path of movement of the steel through the mold.
  • the mixture of inert gas and flux powder forms a layer atop the molten steel, and the thickness of the layer is controlled so that it is less than the length of the stroke of the oscillating mold.
  • a method in accordance with the present invention eliminates mold explosions during the vertical continuous casting of molten steel containing bismuth or lead, without employing the complicated procedure described in Engeler.
  • a preferred lubricant in accordance with the present invention is molybdenum disulfide.
  • Other lubricants which may be used in accordance with the present invention are lithium sulfide and graphite.
  • the non-organic compound employed as a lubricant in accordance with the present invention is devoid of liquified inert gases, such as liquid nitrogen.
  • the method of the present invention may further comprise providing a lubricant-containing layer atop the molten steel in said mold no earlier than when the mold has been at least partially filled with said molten steel; maintaining said layer atop the molten steel substantially throughout the casting operation; and oscillating said mold back and forth along the path of movement of said steel through said mold, said oscillation having a predetermined stroke length; the thickness of said lubricant-containing layer being independent of the length of the stroke of the oscillating mold.
  • the molten steel may also contain tellurium and the method of the present invention is equally effective in preventing mold explosions when tellurium is additionally present in the molten steel.
  • the lubricant-containing layer may comprise a flux powder which is chemically and thermally relatively passive in the presence of molten steel containing lead and/or bismuth, under the conditions of continuous casting existing within the mold, to avoid explosions, and being incapable of producing a breakdown compound, under said conditions, which is explosive under said conditions.
  • the present invention is employed in connection with molten steel containing at least one of the machinability increasing ingredients lead and bismuth, alone or in combination, in machinability increasing amounts.
  • the steel may also contain tellurium as an additional machinability increasing ingredient.
  • Typical examples of machinability increasing amounts for each of these ingredients are: 0.05-0.50 wt.% lead; 0.04-40 wt.% bismuth; and 0.02-0.06 wt.% tellurium.
  • the present invention is applicable to any steel composition heretofore containing these elements as described in the preceding part of this paragraph.
  • Molten steel having a composition in accordance with the preceding paragraph is introduced into a vertically disposed continuous casting mold having sidewalls with an interior surface coated with a lubricant in accordance with the present invention.
  • the lubricant is preferably molybdenum disulfide.
  • Other lubricants which may be employed comprise lithium sulfide and powdered graphite. This lubricant does not contain liquified inert gases, such as liquid nitrogen.
  • the lubricant is applied to the interior surface of the mold walls before the molten steel is introduced into the mold.
  • the solid steel shell with incompletely solidified molten steel therein advances through the mold without sticking to the side walls of the mold, and there are no mold explosions.
  • Excluded from the interior of the mold is any organic compound which produces explosions under the conditions existing within the mold during continuous casting,.
  • petroleum based oils conventionally used as a mold lubricant in the continuous casting of molten steel, and this includes white mineral oil among the excluded organic compounds when the molten steel contains bismuth.
  • a flux powder composed of non-organic material is added atop the molten steel and maintained there during substantially the rest of the casting operation.
  • the flux powder may be of any conventional composition heretofore used for that purpose provided that the flux powder is not violently reactive chemically or thermally, under the conditions of continuous casting existing within the mold, to produce explosions, and does not break down under such conditions to produce a compound which is explosive under such conditions.
  • Such flux powder can also provide a lubricant between the molten steel and the interior surface of the mold walls at a time during the casting operation when the lubricant applied before the start of the casting operation has worn off.
  • Three examples of such flux powders, identified as A-C respectively, are substantially as set forth below.
  • the mold may be oscillated back and forth along the path of movement of the steel through the mold (i.e., up and down oscillation).
  • the oscillation has a predetermined stroke length, but there is no requirement that one relate the thickness of any lubricant-containing layer atop the molten steel in the mold to the length of the stroke of the oscillating mold.
  • a typical continuous casting mold with which the present invention is employed has cross sectional dimensions of 360 mm by 520 mm and a depth of 500 mm to the dummy bar, at the start of the casting operation. In such a mold, about 150 grams of aluminum wire is employed.
  • the lubricant employed in the present invention is not violently reactive thermally or chemically under the conditions of continuous casting existing within the mold, and thus it will not produce explosions, and it does not break down under those conditions to produce a compound which is explosive under those conditions. This is in contrast to lubricating oils conventionally utilized as a mold lubricant in the continuous casting of molten steel. Such lubricants will cause mold explosions when the steel contains lead, bismuth or tellurium, and thus must be excluded from the mold during the continuous casting of molten steel containing those ingredients.
  • White mineral oil heretofore employed as a lubricant for molten steel containing tellurium may not be employed as a lubricant when the molten steel contains bismuth because the white mineral oil will cause mold explosions if employed in the continuous casting of molten steel containing that ingredient.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Continuous Casting (AREA)

Claims (10)

1. Procédé pour la coulée verticale continue d'aciers à usinage facile contenant au moins l'un des éléments bismuth et plomb, dans lequel (a) ledit acier en fusion est introduit dans un moule de coulée continue ayant une surface interne, (b) ledit acier en fusion est au moins partiellement solidifié dans ledit moule pour former une enveloppe solide, (c) ladite surface interne est lubrifiée par un lubrifiant de moule non métallique non organique pour empêcher ladite enveloppe d'adhérer à ladite surface interne au cours de la coulée, (d) ledit lubrifiant est appliqué d'une manière transitoire selon laquelle le lubrifiant s'use au cours d'une opération de coulée, (e) ledit lubrifiant est thermiquement et chimiquement relativement passif, en présence d'un acier en fusion contenant du plomb et/ou du bismuth, dans les conditions existant à l'intérieur dudit moule, pour éviter les explosions, (f) ledit lubrifiant est incapable de produire un composé de dégradation, dans lesdites conditions, qui soit explosif dans lesdites conditions, et (g) il est exclu dudit moule tout composé organique produisant des explosions dans lesdites conditions, ledit procédé étant caractérisé par l'étape comprenant: l'application directement sur la surface interne dudit moule, avant le début de chaque opération de coulée, du lubrifiant dépourvu de gaz liquéfié.
2. Procédé selon la revendication 1, dans lequel ladite matière non organique est le disulfure de molybdène.
3. Procédé selon la revendication 1, dans lequel ladite matière non organique est le sulfure de lithium.
4. Procédé selon la revendication 1, dans lequel ladite matière non organique est le graphite.
5. Procédé selon l'une des revendications 1 à 4, dans lequel ledit composé organique exclu est une huile.
6. Procédé selon la revendication 5, dans lequel l'huile exclue est un composé utilisé de façon conventionnelle comme lubrifiant de moule dans la coulée continue de l'acier en fusion.
7. Procédé selon l'une des revendications précédentes et comprenant en outre:
le fait de prévoir une couche contenant un lubrifiant sur l'acier en fusion dans ledit moule pas avant que le moule ne soit au moins partiellement rempli par ledit acier en fusion,
le maintien de ladite couche sur l'acier en fusion sensiblement pendant toute l'opération de coulée,
et l'oscillation dudit moule dans la direction du mouvement dudit acier dans ledit moule, ladite oscillation ayant une longueur de course prédéterminée,
l'épaisseur de ladite couche contenant un lubrifiant étant indépendante de la longueur de la course du moule oscillant.
8. Procédé selon J'une des revendications précédentes, dans lequel ladite matière non organique est dépourvue de gaz inerte liquéfié.
9. Procédé selon l'une des revendications précédentes, dans lequel ledit acier en fusion contient aussi du tellure en des quantités améliorant l'usinabilité.
10. Procédé selon la revendication 7, dans lequel ladite couche contenant un lubrifiant comprend une poudre de fondant qui est chimiquement et thermiquement relativement passive en présence d'un acier en fusion contenant du plomb et/ou du bismuth, dans les conditions de coulée continue existant à l'intérieur du moule, pour éviter les explosions, et qui est incapable de produire un composé de dégradation, dans lesdites conditions, qui soit explosif dans lesdites conditions.
EP86115363A 1985-11-12 1986-11-05 Procédé pour éviter des explosions de moules pendant la coulée continue d'aciers de décolletages Expired - Lifetime EP0222321B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US79699285A 1985-11-12 1985-11-12
US796992 1985-11-12

Publications (3)

Publication Number Publication Date
EP0222321A2 EP0222321A2 (fr) 1987-05-20
EP0222321A3 EP0222321A3 (en) 1987-08-26
EP0222321B1 true EP0222321B1 (fr) 1990-08-08

Family

ID=25169611

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86115363A Expired - Lifetime EP0222321B1 (fr) 1985-11-12 1986-11-05 Procédé pour éviter des explosions de moules pendant la coulée continue d'aciers de décolletages

Country Status (9)

Country Link
EP (1) EP0222321B1 (fr)
AU (1) AU584560B2 (fr)
BR (1) BR8605567A (fr)
CA (1) CA1272009A (fr)
DE (1) DE3673333D1 (fr)
ES (1) ES2002062A6 (fr)
IN (1) IN168774B (fr)
MX (1) MX168543B (fr)
ZA (1) ZA868231B (fr)

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH455165A (de) * 1966-12-23 1968-04-30 Concast Ag Verfahren zum Stranggiessen von Stahl
GB1242925A (en) * 1969-02-19 1971-08-18 Monsanto Chemicals Improved ceramic moulds for metal casting
US3965916A (en) * 1974-12-23 1976-06-29 Chevron Research Company Apparatus and method for gagging a relief valve within a flue secured to a tank
CH611189A5 (fr) * 1976-12-28 1979-05-31 Belipar Sa
US4120344A (en) * 1977-07-20 1978-10-17 Standard Oil Company (Indiana) Method of continuous casting tellurium containing steels
JPS5519428A (en) * 1978-07-28 1980-02-12 Sumitomo Metal Ind Ltd Lubricating method in casting mold of horizontal continuous casting method

Also Published As

Publication number Publication date
ZA868231B (en) 1987-07-29
IN168774B (fr) 1991-06-01
ES2002062A6 (es) 1988-07-01
EP0222321A2 (fr) 1987-05-20
AU6502086A (en) 1987-05-14
MX168543B (es) 1993-05-31
AU584560B2 (en) 1989-05-25
CA1272009A (fr) 1990-07-31
BR8605567A (pt) 1987-08-18
DE3673333D1 (de) 1990-09-13
EP0222321A3 (en) 1987-08-26

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