EP0235340B1 - An anode system for plasma heating usable in a tundish - Google Patents
An anode system for plasma heating usable in a tundish Download PDFInfo
- Publication number
- EP0235340B1 EP0235340B1 EP86103047A EP86103047A EP0235340B1 EP 0235340 B1 EP0235340 B1 EP 0235340B1 EP 86103047 A EP86103047 A EP 86103047A EP 86103047 A EP86103047 A EP 86103047A EP 0235340 B1 EP0235340 B1 EP 0235340B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- tundish
- molten metal
- anode system
- conductive member
- electrical conductive
- 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
- 238000010438 heat treatment Methods 0.000 title claims description 13
- 239000002184 metal Substances 0.000 claims description 63
- 229910000831 Steel Inorganic materials 0.000 claims description 11
- 239000010959 steel Substances 0.000 claims description 11
- 238000009749 continuous casting Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 2
- 230000004048 modification Effects 0.000 description 8
- 238000012986 modification Methods 0.000 description 8
- 239000011449 brick Substances 0.000 description 6
- 238000000034 method Methods 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
Images
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
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D41/00—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like
- B22D41/005—Casting melt-holding vessels, e.g. ladles, tundishes, cups or the like with heating or cooling means
- B22D41/01—Heating means
Definitions
- the present invention relates to an anode system for plasma heating for use in a tundish of a continuous casting apparatus according to the preamble of claim 1.
- the main object of the present invention is to provide such anode systems which are economical and simple in structure and can be used for a long period of time under severe service conditions.
- the plasma heating device comprises a power source, a plasma torch (cathode) for generating a plasma arc, which makes an electrical path between the molten metal and the plasma torch and an electrode (anode) to supply current into the molten metal.
- the current supplying electrode is formed by placing electric conductive carbon bricks on the bottom surface of a stationary furnace, such as a melting furnace, and connecting a lead wire to the brick formation to provide a current path, or by forming part of the botteom portion of the furnace with a metal having a similar composition as the metal to be melted in the furnace instead of the bricks, and projecting part of the metal formation outside the furnace in the form of fins for necessary cooling.
- a stationary furnace such as a melting furnace
- the current supplying electrode is considerably melted by the molten metal, the molten metal pool remaining after the pouring of the molten metal from the furnace is allowed to solidify again prior to a subsequent charge of the furnace and this solidified metal can be used as part of the electrode.
- the electrode provided on the furnace bottom is very often damaged, and once damaged, must be replacecd with a new one. Therefore, the service life of the current supplying electrodes according to the conventional systems are very short when used in the tundish.
- the tundish itself is more often replaced and the brick works are more frequently replaced as compared with the stationary furnaces, and each replacement of the tundish or the brick works requires renewal of the electrode, thur increasing the running cost of the tundish operation and complicating the over-all works including the tundish replacement and the brick works replacement.
- JP-A 58 100 951 discloses a temperature controlling method for molten steel for continuous casting.
- a part of the molten steel is solidified in a tundish as an electrode, and a plasma arc is applied to the surface of the molten steel to heat the molten steel.
- the electrode (anode) contacting the molten steel is inserted through the upper side of the tundish, and in order to extend the life of the electrode, the molten steel is solidified in the part of the tundish where the electrode is inserted.
- This part of the tundish is provided with a partition.
- the anode system acccording to the present invention comprises a dam member provided on the bottom surface of a tundish near and along a side wall of a tundish near and along a side wall or an over-flow wall of the tundish to form a space or gab therebetween, an electrical conductive member with its end portion exposed to the space or gap and the other end electrically connected to a power source, said dam member having a height higher than a level of molten metal remaining after the pouring of the molten metal from the tundish, but lower than a minimum level of molten metal normally contained in the tundish.
- the anode in the form of wire or strip is inserted through a hole provided in the side wall or bottom wall of the tundish into the space formed between the side wall and the dam member or between the over-flow wall provided on the bottom of the tundish and the dam member.
- the electrical conductive member is placed on the inside of the side wall along its height and part of the bottom adjacent to the side wall, with the end portion projecting into the space or gap between the side wall or the over-flow wall and the dam member and the portion exposed to the molten metal in the tundish being covered by refractories for protection from the molten metal.
- the side wall used in the present invention includes the short side wall and the long side wall.
- the pouring of the molten metal into a mold is continuously performed, while the supply of the molten metal into the tundish is made from a ladle, and when one ladle is poured out this vacant ladle must be changed by another ladle to continue the supply of the molten metal to the tundish.
- the supply of the molten metal is stopped temporarily, so that the level of molton metal in the ladle lowers.
- the level of molton metal in the tundish lowers, the amount of slag mixed in the molten metal and entangled into the mold increases. Therefore, in the practice of tundish operation, it is necessary to maintain the level of molten metal in the tundish not lower than a predetermined level.
- This level is called the minimum level of the molten metal normally contained in the tundish, and is determined in view of the design of a tundish, a final product quality to be sought, etc. Usually this minimum level is about 400 to 450 mm from the bottom surface.
- the level of molten metal remaining after pouring out of the molten metal from the tundish comes about 150 to 200 mm from the bottom surface of the tundish.
- 1 is a tundish
- 2 is a cover for the tundish
- 3 is a molten metal contained in the tundish
- 3a represents the maximum level of the molton metal normally contained in the tundish
- 3b represents the minimum level of the molten metal normally contained in the tundish at the time of ladle change
- 3c represents the level of the molten metal remaining in the tundish after the pouring-out of the molten metal from the tundish.
- 4 is a cover for a heating chamber provided at the top of the tundish, through which the plasma torch 5 electrically connected to the power source through a cable is inserted into heating chamber.
- 6 is the refractory dam meber according to the present invention.
- 7 is an electrical conductive member (anode) with its front end projecting into the space or gab, and the other end being electrically connected to the power source through a cable 9.
- the current passage to the molten metal 3 in the tundish is effected through the electrical conductive member 7, and the molten metal flowing into the space or gap or the solidified metal 8 in the space or gap.
- the dam member 6 has a height lower than the minimum level 3b (about 400 to 450 mm - preferably 350 to 400 mm - from the bottom surface) of the molten metal normally contained in the tundish at the time of the ladle change but higher than the level 3c (about 150 to 250 mm preferably 150 to 200 mm from the bottom surface) of the molten metal remaining in the tundish after the pouring out of the molten metal from the tundish.
- the dam member bridges between the opposing longitudinal side walls of the tundish preferably in constant heigt.
- the dam member may be - shaped extending from the side wall and surrounding the electrical member.
- the dam member With the satisfaction of the height conditions of the dam member as defined above, ad the dam member is lower than the minimum level 3b of the molten metal, the current passage to the molten metal can be smoothly effected even at the time of ladle change when the level of the molten metal lowers to the minimum level 3b.
- the solidified metal in the space can never be pysically connected to the solidified metal remaining in the tundish because of the existence of the dam member therebetween, so that the solidified metal 8 in the space is not removed even when the solidified metal remaining on the bottom of the tundish is removed and can be retained in the space serving as a component of the anode permanently without the damage of the dam member, and the side wall refractory around the hole through which the anode is inserted.
- the electrical conductive material is inserted through the short side wall of the tundish, but it may be inserted through the longitudinal side wall or bottom wall of the tundish, and the space between the dam member and the side wall may be provided between an over-flow wall (2c in Figures 3 (a), (b)), in cases where such an over-flow wall is provided in the tundish, and the dam member provided near the over-flow wall.
- the space formed between the over-flow wall and the dam member functions similarly as the space formed between the side wall and the dam member.
- FIGs 2 (a) and 2 (b) showing another modica- tion of the present invention 6 is a dam member of the same structure and design as the dam member shown in Figure 1, 8 is a refractory cover for the conductive member 7 which is formed in a hooked shape, made of steel.
- the conductive member 7 is inserted into the tundish from upward and runs along the height of the side wall 2b and part of the bottom 2a of the tundish into the space formed between the dam member and the refractory cover 8, with the rising end portion 7c projecting into the space, preferably up to the height of the dam member.
- the refractory cover 8 covers the portion 7a running on the side wall and the portion 7b running on the bottom so as to protect the conductive member from the attack of the molten metal in the tundish.
- the rising portion projecting into the space, when brought into contact with the molten metal is melted by the molten metal during the tundish operation.
- the embodiment shown in Figures 2 (a) and 2 (b) has the advantaged that as the rising end portion 7c initially projects into the space up to the height of the dam member, it is no more necessary for the conductive member to wait for the flowing-in of the molten metal into the narrow space between the side wall and the dam member as in the embodiment shown in Figure 1, and as the conductive member is not inserted through the side wall there is no danger of leaking of the molten metal through the hole of the side wall.
- the over-flow wall is used for removing an excessive amount of the molten metal from the tundish.
- This modified embodiment produces the same results as the embodiment shown in Figures 2 (a) and 2 (b).
- the anode assembly is formed by utilizing the longitudinal side wall 2d of the tundish.
- the dam member 6 extends from the side wall in a shape surrounding the electrical conductive member 7.
- the anode system according to the present invention can be used almost permanently for the plasma heating in the tundish and is very economical and simple in the structure.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Support Devices, Ladles, And Melt Control Thereby (AREA)
Description
- The present invention relates to an anode system for plasma heating for use in a tundish of a continuous casting apparatus according to the preamble of claim 1.
- The main object of the present invention is to provide such anode systems which are economical and simple in structure and can be used for a long period of time under severe service conditions.
- For heating molten metal, such as molten steel in various metallurgical furnaces, the adoption of plasma heating has been becoming more and more common in recent years. In principle, the plasma heating device comprises a power source, a plasma torch (cathode) for generating a plasma arc, which makes an electrical path between the molten metal and the plasma torch and an electrode (anode) to supply current into the molten metal. Conventionally, the current supplying electrode (anode) is formed by placing electric conductive carbon bricks on the bottom surface of a stationary furnace, such as a melting furnace, and connecting a lead wire to the brick formation to provide a current path, or by forming part of the botteom portion of the furnace with a metal having a similar composition as the metal to be melted in the furnace instead of the bricks, and projecting part of the metal formation outside the furnace in the form of fins for necessary cooling. In the latter system, although the current supplying electrode is considerably melted by the molten metal, the molten metal pool remaining after the pouring of the molten metal from the furnace is allowed to solidify again prior to a subsequent charge of the furnace and this solidified metal can be used as part of the electrode.
- However, in cases where the plasma heating is utilized for heating a molten metal in a tundish of a continuous casting apparatus as disclosed in DE-B 1 288 760, the current supplying electrodes according to the above two systems habe been confronted with the following problems.
- In the case of the tundish of a continuous casting apparatus, as well known, it is necessary to strip off the solidisfied metal remaining on the bottom of the tundish after the pouring and during this removal operation, the electrode provided on the furnace bottom is very often damaged, and once damaged, must be replacecd with a new one. Therefore, the service life of the current supplying electrodes according to the conventional systems are very short when used in the tundish. In addition, the tundish itself is more often replaced and the brick works are more frequently replaced as compared with the stationary furnaces, and each replacement of the tundish or the brick works requires renewal of the electrode, thur increasing the running cost of the tundish operation and complicating the over-all works including the tundish replacement and the brick works replacement.
- Under such situations, an upper-insertion type of current supplying electrode has been proposed for the plasma heating usable in the tundish in a continuous cast in an appartus as disclosed in JP-A 59 107755. This type of anode, however, has technical and economical problems such that it is necessary to prevent the melting of the anode itself in order to increase the service life, and for this precious material must be used. For these reasons, the proposed anode has not yet been commercially used with success.
- JP-A 58 100 951 discloses a temperature controlling method for molten steel for continuous casting. In this method a part of the molten steel is solidified in a tundish as an electrode, and a plasma arc is applied to the surface of the molten steel to heat the molten steel. The electrode (anode) contacting the molten steel is inserted through the upper side of the tundish, and in order to extend the life of the electrode, the molten steel is solidified in the part of the tundish where the electrode is inserted. This part of the tundish is provided with a partition. With the method according JP-A 58 100 951 the current can no longer be passed to the molten steel, if the level of the molten steel is lowered.
- It is an object the present invention to provide an improved structure of an anode system for plasma heating usable in the tundish of a continuous casting apparatus, which is economical and simple in structure and can enjoy a long service life. This object is achieved by the anode system according to the claims.
- The anode system acccording to the present invention comprises a dam member provided on the bottom surface of a tundish near and along a side wall of a tundish near and along a side wall or an over-flow wall of the tundish to form a space or gab therebetween, an electrical conductive member with its end portion exposed to the space or gap and the other end electrically connected to a power source, said dam member having a height higher than a level of molten metal remaining after the pouring of the molten metal from the tundish, but lower than a minimum level of molten metal normally contained in the tundish.
- According to one embodiment of the present invention, the anode in the form of wire or strip is inserted through a hole provided in the side wall or bottom wall of the tundish into the space formed between the side wall and the dam member or between the over-flow wall provided on the bottom of the tundish and the dam member.
- According to a further modification of the present invention, the electrical conductive member is placed on the inside of the side wall along its height and part of the bottom adjacent to the side wall, with the end portion projecting into the space or gap between the side wall or the over-flow wall and the dam member and the portion exposed to the molten metal in the tundish being covered by refractories for protection from the molten metal.
- The side wall used in the present invention includes the short side wall and the long side wall.
- Generally, during the operation of the tundish, the pouring of the molten metal into a mold is continuously performed, while the supply of the molten metal into the tundish is made from a ladle, and when one ladle is poured out this vacant ladle must be changed by another ladle to continue the supply of the molten metal to the tundish. However, at the time of this ladle change, the supply of the molten metal is stopped temporarily, so that the level of molton metal in the ladle lowers.
- As the level of molton metal in the tundish lowers, the amount of slag mixed in the molten metal and entangled into the mold increases. Therefore, in the practice of tundish operation, it is necessary to maintain the level of molten metal in the tundish not lower than a predetermined level. This level is called the minimum level of the molten metal normally contained in the tundish, and is determined in view of the design of a tundish, a final product quality to be sought, etc. Usually this minimum level is about 400 to 450 mm from the bottom surface.
- Also it is desirable to retain and allow a certain amount of molten metal to solidify in the tundish after the pouring of the molten metal from the tundish in order to efficiently strip off the coating material from the bottom surface of the tundish together with the solidified metal. This is called the level of molten metal remaining after pouring out of the molten metal from the tundish. Usually this level comes about 150 to 200 mm from the bottom surface of the tundish.
- The invention is explaned in more detail in connection with the accompanying drawings, in which
- Figure 1 schematically shows the anode system according to one embodiment of the present invention,
- Figures 2 (a) and (b) schematically show the anode system according to a modification of the present invention,
- Figures 3 (a) and (b) schematically show the anode system according to another modification of the present invention, and
- Figure 4 schematically shows the anode system according to a further modification of the present invention.
- The present invention will be more clearly and better understood from the following description of the preferred embodiments with reference to the accompanying drawings.
- In Figure 1, 1 is a tundish, 2 is a cover for the tundish, 3 is a molten metal contained in the tundish, 3a represents the maximum level of the molton metal normally contained in the tundish, 3b represents the minimum level of the molten metal normally contained in the tundish at the time of ladle change and 3c represents the level of the molten metal remaining in the tundish after the pouring-out of the molten metal from the tundish. 4 is a cover for a heating chamber provided at the top of the tundish, through which the
plasma torch 5 electrically connected to the power source through a cable is inserted into heating chamber. 6 is the refractory dam meber according to the present invention. In this embodiment, the dam member is provided on the bottom near the short side wall of the tundish to provide a space or gap (b = 3 to 4 cm) therebetween. 7 is an electrical conductive member (anode) with its front end projecting into the space or gab, and the other end being electrically connected to the power source through acable 9. - The current passage to the
molten metal 3 in the tundish is effected through the electricalconductive member 7, and the molten metal flowing into the space or gap or thesolidified metal 8 in the space or gap. - According to the present invention, it is necessary that the
dam member 6 has a height lower than theminimum level 3b (about 400 to 450 mm - preferably 350 to 400 mm - from the bottom surface) of the molten metal normally contained in the tundish at the time of the ladle change but higher than thelevel 3c (about 150 to 250 mm preferably 150 to 200 mm from the bottom surface) of the molten metal remaining in the tundish after the pouring out of the molten metal from the tundish. In this embodiment, the dam member bridges between the opposing longitudinal side walls of the tundish preferably in constant heigt. However, the dam member may be - shaped extending from the side wall and surrounding the electrical member. - With the satisfaction of the height conditions of the dam member as defined above, ad the dam member is lower than the
minimum level 3b of the molten metal, the current passage to the molten metal can be smoothly effected even at the time of ladle change when the level of the molten metal lowers to theminimum level 3b. On the other hand, as the dam member is higher than thelevel 3c of the molten metal remaining in the tundish after the pouring of the molten metal from the tundish, the solidified metal in the space can never be pysically connected to the solidified metal remaining in the tundish because of the existence of the dam member therebetween, so that thesolidified metal 8 in the space is not removed even when the solidified metal remaining on the bottom of the tundish is removed and can be retained in the space serving as a component of the anode permanently without the damage of the dam member, and the side wall refractory around the hole through which the anode is inserted. - In the above embodiment, the electrical conductive material is inserted through the short side wall of the tundish, but it may be inserted through the longitudinal side wall or bottom wall of the tundish, and the space between the dam member and the side wall may be provided between an over-flow wall (2c in Figures 3 (a), (b)), in cases where such an over-flow wall is provided in the tundish, and the dam member provided near the over-flow wall. The space formed between the over-flow wall and the dam member functions similarly as the space formed between the side wall and the dam member.
- In Figures 2 (a) and 2 (b) showing another modica- tion of the present invention, 6 is a dam member of the same structure and design as the dam member shown in Figure 1, 8 is a refractory cover for the
conductive member 7 which is formed in a hooked shape, made of steel. In this modification, theconductive member 7 is inserted into the tundish from upward and runs along the height of theside wall 2b and part of thebottom 2a of the tundish into the space formed between the dam member and therefractory cover 8, with the risingend portion 7c projecting into the space, preferably up to the height of the dam member. Therefractory cover 8 covers theportion 7a running on the side wall and theportion 7b running on the bottom so as to protect the conductive member from the attack of the molten metal in the tundish. The rising portion projecting into the space, when brought into contact with the molten metal is melted by the molten metal during the tundish operation. - In addition to the advantages of the embodiments shown in Figure 1, the embodiment shown in Figures 2 (a) and 2 (b) has the advantaged that as the rising
end portion 7c initially projects into the space up to the height of the dam member, it is no more necessary for the conductive member to wait for the flowing-in of the molten metal into the narrow space between the side wall and the dam member as in the embodiment shown in Figure 1, and as the conductive member is not inserted through the side wall there is no danger of leaking of the molten metal through the hole of the side wall. - In Figures 3 (a) and 3 (b), the dam member provided near the over-flow
wall 2c and the electricalconductive member 7 is arranged in the same manner as in Figures 2 (a) and 2 (b). - The over-flow wall is used for removing an excessive amount of the molten metal from the tundish. This modified embodiment produces the same results as the embodiment shown in Figures 2 (a) and 2 (b).
- According to another modification of the present invention as shown in Figure 4, the anode assembly is formed by utilizing the
longitudinal side wall 2d of the tundish. In this case, thedam member 6 extends from the side wall in a shape surrounding the electricalconductive member 7. - In this modification also, similar results can be obtained as in the modification shown in Figures 2(a) and 2(b).
- As understood from the foregoing description, the anode system according to the present invention can be used almost permanently for the plasma heating in the tundish and is very economical and simple in the structure.
Claims (7)
characterized in that said dam member (6) is provided on the bottom of the tundish (2), and said dam member (6) having a height higher than a level (3c) of molten metal (3) remaining after pouring out of the molten metal from the tundish (2), but lower than a minimum level (36) of molten metal (3) normally contained in the tundish (2).
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP86103047A EP0235340B1 (en) | 1986-03-07 | 1986-03-07 | An anode system for plasma heating usable in a tundish |
DE8686103047T DE3666161D1 (en) | 1986-03-07 | 1986-03-07 | An anode system for plasma heating usable in a tundish |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP86103047A EP0235340B1 (en) | 1986-03-07 | 1986-03-07 | An anode system for plasma heating usable in a tundish |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0235340A1 EP0235340A1 (en) | 1987-09-09 |
EP0235340B1 true EP0235340B1 (en) | 1989-10-11 |
Family
ID=8194951
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP86103047A Expired EP0235340B1 (en) | 1986-03-07 | 1986-03-07 | An anode system for plasma heating usable in a tundish |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0235340B1 (en) |
DE (1) | DE3666161D1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0694057B2 (en) * | 1987-12-12 | 1994-11-24 | 新日本製鐵株式會社 | Method for producing austenitic stainless steel with excellent seawater resistance |
GB9000818D0 (en) * | 1990-01-15 | 1990-03-14 | Davy Mckee Sheffield | Tundish |
GB9109383D0 (en) * | 1991-05-01 | 1991-06-26 | Boc Group Plc | Heating method and apparatus |
DE4214539C1 (en) * | 1992-04-27 | 1993-07-22 | Mannesmann Ag, 4000 Duesseldorf, De | |
DE4415212C1 (en) * | 1994-04-26 | 1995-11-09 | Mannesmann Ag | Method and device for heating a metallic melt |
CN102896285B (en) * | 2011-07-29 | 2015-12-02 | 宝山钢铁股份有限公司 | A kind of thin strap continuous casting casting method and device |
DE102014119109B4 (en) | 2014-12-18 | 2018-12-13 | Voestalpine Stahl Gmbh | Distributor for continuous casting plants |
CN110871268B (en) * | 2018-09-04 | 2021-10-19 | 上海梅山钢铁股份有限公司 | Equipotential control device and method for plasma heating of continuous casting tundish |
-
1986
- 1986-03-07 DE DE8686103047T patent/DE3666161D1/en not_active Expired
- 1986-03-07 EP EP86103047A patent/EP0235340B1/en not_active Expired
Non-Patent Citations (2)
Title |
---|
PATENT ABSTRACTS OF JAPAN, vol. 9, no. 14 (M-352)[1737], 22nd January 1985; & JP-A-59 163 062 (SHIN NIPPON SEITETSU K.K.) 14-09-1984 * |
PATENT ABSTRACTS OF JAPAN, vol. 9, no. 317 (C-319)[2040], 12th December 1985; & JP-A-60 152 610 (SHIN NIPPON SEITETSU K.K.) 10-08-1985 * |
Also Published As
Publication number | Publication date |
---|---|
EP0235340A1 (en) | 1987-09-09 |
DE3666161D1 (en) | 1989-11-16 |
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