WO1990000242A1 - Scavenging of gas through a melt in a ladle - Google Patents
Scavenging of gas through a melt in a ladle Download PDFInfo
- Publication number
- WO1990000242A1 WO1990000242A1 PCT/SE1988/000356 SE8800356W WO9000242A1 WO 1990000242 A1 WO1990000242 A1 WO 1990000242A1 SE 8800356 W SE8800356 W SE 8800356W WO 9000242 A1 WO9000242 A1 WO 9000242A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- nozzle
- melt
- gas
- pressure
- ladle
- Prior art date
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D1/00—Treatment of fused masses in the ladle or the supply runners before casting
- B22D1/002—Treatment with gases
- B22D1/005—Injection assemblies therefor
Definitions
- the present invention relates to a method for scavenging gas through a melt in a ladle during the processing stage, the gas being supplied through a nozzle device disposed beneath the surface of the ladle bath, and for keeping the nozzle device free of melt during the charging, transport and casting phases.
- scavenging stones have hitherto been employed in the art for supplying the gas.
- a scaven ⁇ ging stone consists of a porous body of ceramic material. The poro ⁇ sity of the material may be of such a nature as to permit the pas ⁇ sage of gas while the melt cannot permeate through the pores.
- scavenging stones is fraught with a number of drawbacks.
- the scavenging stone may, in ad ⁇ dition, become blocked by the adhesion of metal or slag.
- the steel may also break out through the stone.
- the permitted gas pressure is limited, since excessively high gas pressure may destroy the scavenging stone. This drawback limits the gas flow which may be possible.
- the scavenging stone suffers from a poor degree of flexibility in respect of the employment of different gas flows.
- the object of the present invention is to obviate the above- outlined drawbacks inherent in the employment of scavenging stones and to solve the problem of opening and closing of nozzles in ladles.
- the present invention is substantially characterised in that the nozzle device is, by the intermediary of a switchable valve ar ⁇ rangement, connected to a gas supply source of variable gas pressure which causes the nozzle device to assume one open and one substan ⁇ tially closed position, such that the nozzle, at low gas pressure, allows the passage of a gas flow which is sufficient to keep the nozzle free of the melt but is insufficient to influence the melt proper, and, at high gas pressure, allows the passage of a gas flow of such a magnitude that agitation and refining of the melt take place.
- the present invention is further characterised in that the noz ⁇ zle device is of a cross-sectional area in the range of between 0.2 and 15 mm 2 ; that the differential pressure in a substantially closed nozzle, i.e. the difference between the gas pressure in the nozzle and the ferros atic pressure from the melt, is greater than 0.05 bar; and that the differential pressure in an open nozzle lies in the range of between 5 and 250 bar.
- the cross-sectional area lies in the range of between 0.1 and 5.0 mm 2 and the differential pressure for an open nozzle is in the range of between 10 and 50 bar.
- a ladle 1 is shown with a melt 2.
- a nozzle device 3 for scavenging the melt.
- a three-way valve 4 is disposed at the ladle 1 and is connected to the nozzle device 3 and to quick-coupling devices 5 to which conduits from gas supply equipment 6 and 7, respectively, may be connected.
- the nozzle is opened and closed by variable gas pressures. Closure is obtained at low pressure when the nozzle merely allows the passage of a very slight gas flow. However, this flow is of sufficient magnitude to keep the nozzle free of melt but is insufficient to influence the melt proper.
- the pressure is raised, the nozzle allows the passage of a desired gas volume for the contemplated process.
- the pressure is once again reduced and the nozzle closes.
- This opening and closing effect in the nozzle is attained by combining a nozzle of slight inner diameter and a gas supply system which allows for both low and high gas pressures. Two examples are given below of different nozzle cross-sectional areas.
- the differential pressure is, here, taken to mean the difference between the pressure at the nozzle and the ferrostatic pressure from the melt.
- the nozzle is open. If a lower gas flow is required for the processing, a lower operational pressure is selected. Hence, an optimum gas flow may be set for each ladle size and process involved, by selecting nozzle cross-sectional area and gas pressure. At 0.1 bar, the nozzle gives such a slight flow that it is, to all intents and purposes, closed.
- differential pressure is taken to mean the difference between the pressure at the nozzle and the fer ⁇ rostatic pressure from the melt.
- One basic pre-condition for the scavenging system according to the present invention is that a gas flow be always maintained through the nozzle, when the melt is charged into the ladle, which entails that gas must be supplied during the charging, during the transport of the ladle and during the casting process itself. This feature is made possible by the employment of the above-mentioned three-way valve 4 which is disposed on the ladle 1. Through the valve, gas supply to the nozzle device 3 may be effected from dif ⁇ ferent gas supply equipment units.
- a stationary gas supply network 7 is connected, by the intermediary of the quick coupling devices 5, to the valve 4.
- the conduit from the network 7 is disconnected and, in ⁇ stead, the nozzle 3 is supplied via the valve 4 from a mobile gas supply unit which accompanies the ladle during its travel.
- a moving gas hose which supplies the nozzle with gas during transport.
- the nozzle is then connected, by the intermediary of the three-way valve and an available quick coupling, back to a stationary gas supply network.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8702338A SE8702338L (en) | 1987-06-05 | 1987-06-05 | GAS RINSE OF MELMA IN SHAENK |
BR888807911A BR8807911A (en) | 1988-06-28 | 1988-06-28 | GAS INJECTION THROUGH A BATH IN A POT |
PCT/SE1988/000356 WO1990000242A1 (en) | 1987-06-05 | 1988-06-28 | Scavenging of gas through a melt in a ladle |
EP88906850A EP0421990A1 (en) | 1987-06-05 | 1988-06-28 | Scavenging of gas through a melt in a ladle |
NO90905600A NO905600L (en) | 1987-06-05 | 1990-12-27 | PROCEDURE FOR RINSE GAS THROUGH A MELT. |
FI906412A FI906412A0 (en) | 1987-06-05 | 1990-12-27 | RENGOERING AV GAS GENOM SMAELTA I ETT KAERL. |
DK307190A DK307190A (en) | 1987-06-05 | 1990-12-28 | RINSE OF GAS THROUGH A MELT IN A BASEBAG |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8702338A SE8702338L (en) | 1987-06-05 | 1987-06-05 | GAS RINSE OF MELMA IN SHAENK |
PCT/SE1988/000356 WO1990000242A1 (en) | 1987-06-05 | 1988-06-28 | Scavenging of gas through a melt in a ladle |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1990000242A1 true WO1990000242A1 (en) | 1990-01-11 |
Family
ID=26659836
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1988/000356 WO1990000242A1 (en) | 1987-06-05 | 1988-06-28 | Scavenging of gas through a melt in a ladle |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0421990A1 (en) |
DK (1) | DK307190A (en) |
FI (1) | FI906412A0 (en) |
NO (1) | NO905600L (en) |
SE (1) | SE8702338L (en) |
WO (1) | WO1990000242A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2337846A1 (en) * | 1972-08-01 | 1974-02-14 | Uss Eng & Consult | DEVICE AND PROCEDURE FOR THE PROTECTION OF BLOW MOLDS IN STEELWORK VESSELS FROM INGREDIENTS OF MELT |
US4382817A (en) * | 1980-01-02 | 1983-05-10 | Institute De Recherches De La Siderurgie Francaise | Process for periodically and pneumatically stirring a bath of molten metal |
US4395283A (en) * | 1981-02-27 | 1983-07-26 | Nippon Steel Corporation | Method of switching bottom-blown gases and apparatus therefor |
US4397684A (en) * | 1981-03-11 | 1983-08-09 | Institut De Recherches De La Siderurgie Francaise Irsid | Process for pneumatic stirring of a bath of molten metal |
US4420334A (en) * | 1980-09-19 | 1983-12-13 | Kawasaki Steel Corporation | Method for controlling the bottom-blowing gas in top-and-bottom blown converter steel making |
-
1987
- 1987-06-05 SE SE8702338A patent/SE8702338L/en unknown
-
1988
- 1988-06-28 WO PCT/SE1988/000356 patent/WO1990000242A1/en not_active Application Discontinuation
- 1988-06-28 EP EP88906850A patent/EP0421990A1/en not_active Withdrawn
-
1990
- 1990-12-27 FI FI906412A patent/FI906412A0/en not_active Application Discontinuation
- 1990-12-27 NO NO90905600A patent/NO905600L/en unknown
- 1990-12-28 DK DK307190A patent/DK307190A/en not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2337846A1 (en) * | 1972-08-01 | 1974-02-14 | Uss Eng & Consult | DEVICE AND PROCEDURE FOR THE PROTECTION OF BLOW MOLDS IN STEELWORK VESSELS FROM INGREDIENTS OF MELT |
US4382817A (en) * | 1980-01-02 | 1983-05-10 | Institute De Recherches De La Siderurgie Francaise | Process for periodically and pneumatically stirring a bath of molten metal |
US4420334A (en) * | 1980-09-19 | 1983-12-13 | Kawasaki Steel Corporation | Method for controlling the bottom-blowing gas in top-and-bottom blown converter steel making |
US4395283A (en) * | 1981-02-27 | 1983-07-26 | Nippon Steel Corporation | Method of switching bottom-blown gases and apparatus therefor |
US4397684A (en) * | 1981-03-11 | 1983-08-09 | Institut De Recherches De La Siderurgie Francaise Irsid | Process for pneumatic stirring of a bath of molten metal |
Non-Patent Citations (1)
Title |
---|
PATENT ABSTRACTS OF JAPAN, Vol 9, No 52 (C-269) Abstract of JP 59-193227, publ. 1984-11-01 * |
Also Published As
Publication number | Publication date |
---|---|
SE8702338L (en) | 1988-12-06 |
SE8702338D0 (en) | 1987-06-05 |
FI906412A0 (en) | 1990-12-27 |
EP0421990A1 (en) | 1991-04-17 |
DK307190D0 (en) | 1990-12-28 |
NO905600D0 (en) | 1990-12-27 |
DK307190A (en) | 1990-12-28 |
NO905600L (en) | 1990-12-27 |
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