WO2005042183A1 - A method and a device for detecting slag - Google Patents

A method and a device for detecting slag Download PDF

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Publication number
WO2005042183A1
WO2005042183A1 PCT/SE2004/001417 SE2004001417W WO2005042183A1 WO 2005042183 A1 WO2005042183 A1 WO 2005042183A1 SE 2004001417 W SE2004001417 W SE 2004001417W WO 2005042183 A1 WO2005042183 A1 WO 2005042183A1
Authority
WO
WIPO (PCT)
Prior art keywords
slag
tundish
discharge tube
flow
molten metal
Prior art date
Application number
PCT/SE2004/001417
Other languages
French (fr)
Inventor
Seymour Eriksson
Ralph NYSTRÖM
Original Assignee
Mefos-Metallurgical Research Institute Ab
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mefos-Metallurgical Research Institute Ab filed Critical Mefos-Metallurgical Research Institute Ab
Publication of WO2005042183A1 publication Critical patent/WO2005042183A1/en

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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
    • B22D2/00—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass
    • B22D2/001—Arrangement of indicating or measuring devices, e.g. for temperature or viscosity of the fused mass for the slag appearance in a molten metal stream
    • 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
    • B22D41/14—Closures
    • B22D41/16—Closures stopper-rod type, i.e. a stopper-rod being positioned downwardly through the vessel and the metal therein, for selective registry with the pouring opening
    • B22D41/18—Stopper-rods therefor
    • B22D41/186—Stopper-rods therefor with means for injecting a fluid into the melt

Definitions

  • This invention relates to a method for detecting the presence of slag in a flow of molten metal conducted through a discharge tube from a container, wherein the outlet flow to the discharge tube is controlled by a valve and protective gas is supplied to the discharge tube downstream of the valve, and the change in pressure and/or flow that occurs in the supply conduit for protective gas, when the density of the liquid flowing through the tube changes, is used for detecting presence of slag.
  • JP 2003-170257 A shows a slag detection system for detecting flow of slag from ladle to tundish in continuous casting through a slide gate valve. A controlled flow of inert gas is supplied laterally to the discharge tube and the pressure of the supplied gas is measured and used to detect slag intrusion.
  • FIG. 1 shows in a side view a continuous casting system with tundish and mould and a slag detection system by which the invention can be carried out Detailed description of the invention with reference to the drawing
  • Figure 1 shows a device for continuous casting of steel to cast products, e.g. slabs, billets or blooms:
  • the tundish 11 comprises a tundish 11 with a discharge tube 12 that extends into a mould.
  • the level of molten metal 14 in the mould is held substantially constant by being supplied from a ladle.
  • a slag 15 floats on the metal.
  • the mould 14 is water cooled and the molten metal solidifies against it and forms a shell 16 that is continuously drawn downwards out of the mould.
  • a stopper rod 17 can be moved vertically and forms a valve against a conical tap hole so as to control the outlet area from the tundish to the discharge tube.
  • a channel 18 leads axially through the stopper rod and ends in the rounded end of the stopper rod close to the controlled annular exit 25 of molten metal.
  • the channel 18 leads axially through the stopper rod and ends in the rounded end of the stopper rod close to the controlled annular exit 25 of molten metal.
  • a meter 23 is coupled to the supply conduit 19 downstream of the restriction 20 to monitor the flow and/or the pressure in the conduit 19.
  • the meter 23 will register a sudden change in the gas pressure and/or the flow rate of gas in the conduit 19. The change depends on the changed density of the molten metal when it becomes contaminated with slag.
  • the meter can be coupled to a computerised control system for controlling the stopper rod 17 to close when slag is detected.
  • the described method of detecting slag can also be applied to the pouring of molten steel from the ladle to the tundish 11. It can be used simultaneously both for the pouring into the tundish and for the pouring out of the tundish. It can also be applied to other pouring of steel and other metals and alloys. In the ferroalloy industry, the slag can sometimes be heavier than the alloy and in such a case, the slag is first poured out and it is detected when there is no slag but slag free alloy.

Abstract

In continuous casting of metal, e.g. steel, the molten metal is poured from a ladle to a tundish (11) and from the tundish through a discharge tube (12) to a mould (13). The conical outlet to the discharge tube is controlled by a stopper rod (17) that has an axial channel (18). Protective gas from a source (21) is supplied to the channel (18) through a conduit (19) with a restriction (20), and the pressure downstream of the restriction is monitored by a meter (23). When slag flows into the discharge tube when the tundish is close to be empty, the meter (23) senses a pressure change and the stopper rod can be actuated to close.

Description

A method and a device for detecting slag
Technichal field
This invention relates to a method for detecting the presence of slag in a flow of molten metal conducted through a discharge tube from a container, wherein the outlet flow to the discharge tube is controlled by a valve and protective gas is supplied to the discharge tube downstream of the valve, and the change in pressure and/or flow that occurs in the supply conduit for protective gas, when the density of the liquid flowing through the tube changes, is used for detecting presence of slag.
Background of the invention
There is almost always slag together with molten metal in a container for transportation (ladle), in a container for casting (tundish) or in any other metallurgical containers. Usually, the slag floats on the surface and one wants to interrupt the flow when slag appears in the flow during the discharging of molten metal through a controlled bottom outlet nozzle. From the economical point of view, one wants to leave as little molten metal in the container as possible and several slag detecting systems are known in the art. JP 2003-170257 A shows a slag detection system for detecting flow of slag from ladle to tundish in continuous casting through a slide gate valve. A controlled flow of inert gas is supplied laterally to the discharge tube and the pressure of the supplied gas is measured and used to detect slag intrusion.
Object of invention and brief description of the invention
It is an object of the invention to provide an improved slag detection.
To this end a vertical stopper rod (17) is used as valve and the protective gas is supplied through an axial channel (18) in the stopper rod. The invention is defined by the claims
Short description of the single drawing
Figure 1 shows in a side view a continuous casting system with tundish and mould and a slag detection system by which the invention can be carried out Detailed description of the invention with reference to the drawing
Figure 1 shows a device for continuous casting of steel to cast products, e.g. slabs, billets or blooms:
It comprises a tundish 11 with a discharge tube 12 that extends into a mould. The level of molten metal 14 in the mould is held substantially constant by being supplied from a ladle. A slag 15 floats on the metal. The mould 14 is water cooled and the molten metal solidifies against it and forms a shell 16 that is continuously drawn downwards out of the mould. A stopper rod 17 can be moved vertically and forms a valve against a conical tap hole so as to control the outlet area from the tundish to the discharge tube. A channel 18 leads axially through the stopper rod and ends in the rounded end of the stopper rod close to the controlled annular exit 25 of molten metal. The channel
18 is coupled to a supply conduit 19 for protective gas, usually an inert gas such as argon, from a source of gas 21 through a restriction 20. A meter 23 is coupled to the supply conduit 19 downstream of the restriction 20 to monitor the flow and/or the pressure in the conduit 19.
As little as possible of molten metal should be left in the tundish when the discharge to the mould is interrupted and a new tundish is replaced for the emptied one. However, if there is slag in the metal poured into the mould, the quality of the cast product will be destroyed. When slag enters the discharge tube, the meter 23 will register a sudden change in the gas pressure and/or the flow rate of gas in the conduit 19. The change depends on the changed density of the molten metal when it becomes contaminated with slag. The meter can be coupled to a computerised control system for controlling the stopper rod 17 to close when slag is detected.
The described method of detecting slag can also be applied to the pouring of molten steel from the ladle to the tundish 11. It can be used simultaneously both for the pouring into the tundish and for the pouring out of the tundish. It can also be applied to other pouring of steel and other metals and alloys. In the ferroalloy industry, the slag can sometimes be heavier than the alloy and in such a case, the slag is first poured out and it is detected when there is no slag but slag free alloy.

Claims

Claims
1. A method for detecting the presence of slag in a flow of molten metal (14) conducted through a discharge tube (12) from a container (11), wherein the outlet flow to the discharge tube is controlled by a valve (17) and protective gas is supplied to the discharge tube downstream of the valve, and the change in pressure and/or flow that occurs in the supply conduit (19) for protective gas, when the density in the molten metal flowing through the tube changes, is used for detecting presence of slag, characterised in that a vertical stopper rod (17) is used as valve and the protective gas is supplied through an axial channel (18) in the stopper.
2. A method according to claim 1 used in the continuous casting process for detection of presence of slag in the flow from the tundish (11) to the mould (13).
3. Amethod according to claim 2 used also for detection of presence of slag in the flow from the ladle to the tundish.
PCT/SE2004/001417 2003-11-04 2004-10-05 A method and a device for detecting slag WO2005042183A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0302895-8 2003-11-04
SE0302895A SE527477C2 (en) 2003-11-04 2003-11-04 Ways to detect slag blend

Publications (1)

Publication Number Publication Date
WO2005042183A1 true WO2005042183A1 (en) 2005-05-12

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2004/001417 WO2005042183A1 (en) 2003-11-04 2004-10-05 A method and a device for detecting slag

Country Status (2)

Country Link
SE (1) SE527477C2 (en)
WO (1) WO2005042183A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006125662A1 (en) * 2005-05-23 2006-11-30 Strikowestofen Gmbh Melting or holding furnace
EP2233227A1 (en) * 2009-03-23 2010-09-29 Refractory Intellectual Property GmbH & Co. KG Flame-retardant ceramic stops
WO2011071431A1 (en) * 2009-12-08 2011-06-16 Swerea Mefos Ab Arrangement for controlling the flow out of a tundish
WO2016173901A1 (en) * 2015-04-29 2016-11-03 Primetals Technologies Austria GmbH Slag detection in a distributor of a strand casting system
WO2018108789A1 (en) 2016-12-12 2018-06-21 Vesuvius Group, S.A. Stopper equipped with an integrated slag detection device
EP3363560A1 (en) * 2017-02-20 2018-08-22 ABB Schweiz AG A method and stirring system for controlling an electromagnetic stirrer

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0359828A1 (en) * 1988-03-09 1990-03-28 Kawasaki Steel Corporation Method for detecting slag flow
JPH044964A (en) * 1990-04-23 1992-01-09 Kawasaki Steel Corp Method for detecting flowing-out of slag and nozzle used for this method
JP2003170257A (en) * 2001-12-05 2003-06-17 Daido Steel Co Ltd Method and device for detecting slag outflow

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0359828A1 (en) * 1988-03-09 1990-03-28 Kawasaki Steel Corporation Method for detecting slag flow
JPH044964A (en) * 1990-04-23 1992-01-09 Kawasaki Steel Corp Method for detecting flowing-out of slag and nozzle used for this method
JP2003170257A (en) * 2001-12-05 2003-06-17 Daido Steel Co Ltd Method and device for detecting slag outflow

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 016, no. 145 10 April 1992 (1992-04-10) *
PATENT ABSTRACTS OF JAPAN vol. 2003, no. 10 8 October 2003 (2003-10-08) *

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006125662A1 (en) * 2005-05-23 2006-11-30 Strikowestofen Gmbh Melting or holding furnace
RU2488461C2 (en) * 2009-03-23 2013-07-27 Рифрэктори Интеллектуал Проперти Гмбх Унд Ко. Кг Refractory ceramic plug
EP2233227A1 (en) * 2009-03-23 2010-09-29 Refractory Intellectual Property GmbH & Co. KG Flame-retardant ceramic stops
WO2010108572A1 (en) * 2009-03-23 2010-09-30 Refractory Intellectual Property Gmbh & Co. Kg Fireproof ceramic plug
CN102413962A (en) * 2009-03-23 2012-04-11 里弗雷克特里知识产权两合公司 Fireproof ceramic plug
US8708204B2 (en) 2009-12-08 2014-04-29 Swerea Mefos Ab Arrangement for controlling the flow out of a tundish
WO2011071431A1 (en) * 2009-12-08 2011-06-16 Swerea Mefos Ab Arrangement for controlling the flow out of a tundish
WO2016173901A1 (en) * 2015-04-29 2016-11-03 Primetals Technologies Austria GmbH Slag detection in a distributor of a strand casting system
WO2018108789A1 (en) 2016-12-12 2018-06-21 Vesuvius Group, S.A. Stopper equipped with an integrated slag detection device
WO2018108788A1 (en) 2016-12-12 2018-06-21 Vesuvius Group, S.A. Stopper equipped with an integrated temperature measurement device
EP3363560A1 (en) * 2017-02-20 2018-08-22 ABB Schweiz AG A method and stirring system for controlling an electromagnetic stirrer
WO2018149594A1 (en) * 2017-02-20 2018-08-23 Abb Ab A method and stirring system for controlling an electromagnetic stirrer
US10919088B2 (en) 2017-02-20 2021-02-16 Abb Schweiz Ag Method and stirring system for controlling an electromagnetic stirrer

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Publication number Publication date
SE0302895L (en) 2005-05-05
SE527477C2 (en) 2006-03-21
SE0302895D0 (en) 2003-11-04

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