CA2388397A1 - Process for the metallurgical treatment of molten steel in a converter with oxygen top blown onto the molten steel and an oxygen blowing lance - Google Patents

Process for the metallurgical treatment of molten steel in a converter with oxygen top blown onto the molten steel and an oxygen blowing lance Download PDF

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Publication number
CA2388397A1
CA2388397A1 CA002388397A CA2388397A CA2388397A1 CA 2388397 A1 CA2388397 A1 CA 2388397A1 CA 002388397 A CA002388397 A CA 002388397A CA 2388397 A CA2388397 A CA 2388397A CA 2388397 A1 CA2388397 A1 CA 2388397A1
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CA
Canada
Prior art keywords
lance
water
head
oxygen
fact
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.)
Abandoned
Application number
CA002388397A
Other languages
French (fr)
Inventor
Bernd Feldhaus
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.)
Berry Metal Co
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of CA2388397A1 publication Critical patent/CA2388397A1/en
Abandoned legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C7/00Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04Removing impurities by adding a treating agent
    • C21C7/068Decarburising
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/30Regulating or controlling the blowing
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/42Constructional features of converters
    • C21C5/46Details or accessories
    • C21C5/4606Lances or injectors
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21CPROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28Manufacture of steel in the converter
    • C21C5/42Constructional features of converters
    • C21C5/46Details or accessories
    • C21C5/4673Measuring and sampling devices

Abstract

this invention concerns a blowing lance and a procedure for the metallurgical treatment of molten steel in a converter with oxygen top blown over the molten steel. In order to monitor the treatment process the intention is for a temperature probe (21) to be integrated into the water-cooled lance head (2) behind the front end of the lance head (11a) and between the cooling chambers (5-10) formed in the lance head (2). The signal lines (26) of this temperature probe run through the lance body (1), more specifically, in a central protective pipe which has no connections to the cooling medium or to the oxygen conducting channels (15, 16, and 17).

Description

PROCESS FOR THE METALLURGICAL TREATMENT OF MOLTEN STEEL IN A CONVERTER WITH
OXYGEN
TOP BLOWN
For the metallurgical treatment of molten steel in a converter, oxygen is blown onto the top of the molten steel under the control of a blowing lance. The oxygen lance is subjected to a high thermal load during this top blowing, particularly on its front end. It is therefore typical to cool the lance down intensively. The most effective way to cool an oxygen blowing lance is to thoroughly flush die head of the lance with a large volume of cool water under high pressure. The head of the lance is made of a material with good thermal conductivity, such as copper. High temperature peaks up to 3000 degrees C, particularly at the front end of the lance head which is the focus of heat radiating from the surface of the bath as well as wear and tear lead over time to a reduction in the thickness of the cooling chamber walls found in the head of the lance. If there is not enough distance between the head of the lance and the molten metal, the walls can weaken rapidly and suddenly rupture because they have been weakened. Any release of water vaporizes explosively and damages more than just the metallurgical process. If the lance head ruptures, the treatment of the enamel must also be terminated immediately.
SUBSTITUTE SHEET (RULE 26) To avoid the danger of a water release while simultaneously cooling the lance even when the lance is plunged into the molten steel melt, there is a process (DE 35 43 836 C2), which employs two blowing lances used in rotation. These two lances arc cooled alternately and intensively with cool air and then with cool water. The lance in the blow position which is being plunged into the molten steel is cooled with cool air while the other lance outside of the molten steel is cooled intensively with cool water. By repeatedly switching as needed between cool air cooling and cool water cooling the overheating of either lance can be avoided, the advantage of effectively avoiding a water release is the cost of purchasing a second lance.
Starting at this point in the state of technology the invention concerns a process for the refinement of molten steel in a converter with top blown oxygen on the molten steel surface with a water cooled blowing lance made up of a 'shafted' lance body and a lance head.
Furthermore, the invention concerns a water cooled oxygen blowing lance made up of a shafted lance body and lance head, for implementation of this process more specifically, with an oxygen supply that runs through the lance body and flows to blowing nozzles distributed in the lance head and with outlet and inlet passageways for water running through the lance body to the cooling chambers in the lance head.
SUBSTITUTE SHEET (RULE 26) The invention is based on the task of achieving a process as above with which the metallurgical blowing process is monitored and controlled. The invention is also based on the task of creating an oxygen blowing lance that to a great extent is protected from the release of water.
According to the process, the problem is solved in that the temperature in the lance head of the blowing lance. which is transferred from the molten steel to the lance head is monitored using at least one of the temperature probes which are integrated into the lance head and regulated by cooling off with water and/or with an oxygen supply and/or the addition of aggregates and/or the distance of the lance head from the molten metal bath, In the process, the abrasion on the front end of the lance head as a function of the tool life and the temperature curve as a function of the tool life can be primarily considered as correction sizes. With the addition of aggregates it can be assumed that the rate and the time of the addition influence temperature regulation. In particular, scrap for cooling. briquettes, ores, lime and other similar things arc considered as aggregates.
In the invention the temperature of the melting bath surface radiating directly onto the front end of the lance head is detected through the temperature in the lance head. Using this measurement of the temperature the metallurgical process of the refinement can be SUBSTITUTE SHEET (RULE 26) controlled. At the same time the head of the blowing lance can be protected from the release of water through the various individual steps or through a combination of measures.
It is true that it is already known how to determine temperature for water cooled blowing lances (JP 62-278217 A) in the treatment of enamels but such a blowing lance is used in another process and with other objectives. In this process the blowing lance is actually submerged in the enamel and the level of the slag of the molten metal relative to the blowing lance is determined by temperature probes which are staggered inside the lance body. In this known process though, protection from overheating by detecting the temperature of the lance and controlling the~treatment process are not dealt with.
With the oxygen top blowing lance the above task is solved by integrating at least one temperature probe in the lance head behind its front end and between the cooling chambers, the signal. lines of which are ducted through the lance body.
With the invention the temperature of the local area in the lance head can be determined, and from experience used as an indicator of the danger of rupturing. Thus there is a requirement for an immediate reaction to imminent collapse whether it be due to the outside wall of the lance head being too thin or becoming too weak.
SUBSTITUTE SHEET (RULE 26) In order to be able to mount the signal lines of (lie temperature probes simply and to be able to protect them they are in a central, protective pipe. This pipe should not have any connection to the process medium 5 oxygen or to the cooling medium water. This is thus particularly advantageous and contributes to the reliability of operation if the head of the lance is burned down to the temperature probes integrated within it and is therefore open. In this situation it is therefore impossible for there to be a leak of oxygen andlor cooling water. In a preferred set tip the oxygen piping is situated in the middle of the lance head and surrounded with inlet and outlet channels for the cooling water through the formation of coaxial ring channels, where the outermost ring channel is the outlet channel and the center ring channel is the inlet channel.
In order to make the assembly work required when switching out a deteriorated lance head for a new one as easy as possible the temperature probe can be put in a bore hole of a nose saddle of the lance head using a disconnectable adapter which is secured inside the lance head. To ensure an error free measurement of temperature it is advantageous for the temperature probe to be kept in contact with the floor of the bore hole by a spring so that it can conduct heat.
For technical assembly reasons as well as for length compensation with various thermal linear expansions of the protective tube and the oxygen pipe, the protective SUBSTITUTE SHEET (RULE 26) pipe should overlap and seal the adapter like a telescopic sleeve.
In the blowing process the most extreme thermal damage to the oxygen blowing lance is sustained by the lance head. As a result the head of the oxygen lance is subjected to the most wear and tear and should be interchangeable . In order to make it easier to change out the lance head one of the set ups of the invention provides for there being coaxial fittings oil the cooling chambers of the lance heads for continuing coaxial inlet and outlet cool water channels. These fittings may then be welded on to the continuing coaxial inlets and outlet channels.
The invention is explained more clearly in the following with the help of an illustration that shows an example of an implementation. In detail the figures show:
Figure 1 the axial section of an oxygen blowing lance, Figure 2 an axial section of the lower part of the oxygen blowing lance in accordance with Figure 1 as an enlarged drawing, Figure 3 an axial section of the lower part of the oxygen blowing lance in accordance with Figure 1 without the lance head and as an enlarged drawing, SUBSTITUTE SHEET (RULE 26) Figure 4 an axial section of the upper part of the oxygen blowing lance in accordance with Figure 1 and as an enlarged drawing, Figure 5 the cross section of die oxygen blowing lance along the line B-B in Figure 4, a n d Figure 6 cross section of the oxygen blowing lance along the line C-C in Figure 4.
The oxygen blowing lance shown in Figure 1 is made up of a shafted lance body 1 and a lance head 2 which is welded onto the body. For safety reasons, with awareness of the oxygen processing gas that is flowed through die lance, the lowest part of the lance head 2 is made from copper. Another reason for making the decision to use copper as the material for the lance head 2 is the good thermal conductivity of copper which makes it possible to effectively cool the lance head 2 with cooling water during blowing.
The lance head 2 comprises a nozzle head 2a, made of copper, with a crown of a total of six evenly spaced nozzles 3 and 4 in a circle and simply directed outwards, cooling chambers 5, 6, 7, 8, 9 and 10 as well as a central, axial strut 11. Coaxial, tubular fittings 2b, 2c, and 2d, are connected to the outermost cooling chambers which together with the nozzle body 2a form an interchangeable modular unit.
SUBSTITUTE SHEET (RULE 26) The lance body 1 consists of three coaxial tubes 12, 13 and 14 made from steel. Together with the incoming/feed connection piece 12a the inside tube 12 forms a central supply line 15 for the oxygen to be supplied to the blowing nozzles 3 and 4. A close sliding fit for 12a is provided in the upper area between the inside pipe 12 on the inside and the middle and outside tubes 13 and 14 which together form a single unit, on the outside. This close sliding fit at 12a serves for adjustment of the relative linear expansions between the tubes 22, 13 and 14 and the assembly of the lance body 2.
Conduits 16 and 17 are developed between the inside tube ~12 and the outside tube 14 as well as tube 13 that lies in between them. Of these conduits, the inside conduit 16 is the supply conduit and the outside conduit 17 forms the outlet conduit for the cooling water that is to be forced through the channels under high pressure. The cooling water is brought in and let out via laterally placed fittings 18 and 19.
In the central strut 11 of the nozzle head 2a there is a bore hole 20 into which an engaging and disengaging, rod-shaped thermoelectric couple is plugged in as the temperature probe 21. The temperature probe 21 is centered by an adapter 22 and held with its end in contact with die floor of the bore hole 20, which is recessed just a few millimeters opposite the front end 11a of the nozzle body. The adapter 22 is fastened with screws to the inside of the nozzle body. The temperature probe 21 is movable and stored in the adapter 22 and SUBSTITUTE SHEET (RULE 26) 'forced towards the floor of the bore hole 20 by a spring 23 that is supported on a regulating screw 25 screwed into the adapter 22. Signal lines 26, which are installed in a central protective pipe 27, go out from the temperature probe 21. The lower end 27a of this protective pipe and the upper end 22a of the adapter 22 form a sealed, telescopic sleeve which makes it easier to switch out the lance head 2 and allows for various linear expansions of the approximately 20 meter long pipes 27 and 12.
The protective pipe 27 is kept centered oil several axially distributed places on the inside walling of the inside tube 12 using springed, radial supporting elements 29 which allow for relative axial motion of the protective pipe 27 compared with this tube 12. The protective pipe 27 is attached directly to the tube 12 only at the top with radial struts 30 and scaled free from tube 12 and open to the atmosphere.
Because of the close sliding fit 12a with potential axial movement of the inside tube 12 and the middle as well as the outside tubes 13 and 14, to fit the lance body 1 with a new lance head 2, the regulating screw 25 is first screwed into the adapter 22 with the rod-shaped temperature probe 21. By doing this the adapter 22 is already preassembled on the inside of the nozzle body 2a so that the temperature probe 21 sits -securely in the bore hole 20 after the regulating screw 25 is screwed in.
. The nozzle body 2a is then connected with its fitting 2d SUBSTITUTE SHEET (RULE 26) to the inside tube 12 on the point of separation 31 and welded on. Tn this way the middle and the outside tubes 13 and 14 are pushed back on to the inside tube 12 and the middle tube 13 respectively. Finally, the middle tube 5 13 and the outside tube 14 are brought close to the fittings 2b and 2c, where the middle tube 13 overlaps the fitting 2c with a close sliding fit and the outside tube 14 is welded on. The removal of a worn out lance head 2 is done in reverse sequence.
The special advantages of the invention are that the temperature is monitored at the places of an oxygen blowing lance which are critical with regard to a release of water, that is the front end 11a of the nozzle head that lies opposite the sensor focal point. In this way counteractive steps can be taken with as little delay as possible when there is the threat of a rupture, whether it be due to the mechanical wear and tear of the remaining wall thickness of the cooling chamber, or due to weakening of die chamber walls because of high thermal peaks when there is insufficient cooling during dismantling. Because of the practically immediate determination of the actual temperature is also possible to consider die march of temperature over time when choosing what measures to take, using which a rupture can be counteracted. Finally, it is an advantage that it is not only possible to protect the actual oxygen blowing lance from ruptures but that it is also possible to influence the factors which have an effect on temperature determination and on the regulation of the metallurgical SUBSTITUTE SHEET (RULE 26) treatment such as the inflow of oxygen, the distance of the lance head from the surface of the molten metal bath etc. to positively influence the refinement process. If for example a temperature is taken that falls far below the critical limit for a lance to rupture, a targeted reduction in the distance between the lance head and the surface of the molten metal bath is possible, through which the refinement process is accelerated and made more efficient.
SUBSTITUTE SHEET (RULE 26)

Claims (10)

12
1. Procedure for the refinement of molten metal in a converter with oxygen top blown onto the surface of the molten metal bath from a blowing lance consisting of one lance body (1) of the shafted type cooled by water and a lance head (2) characterized by the fact that the temperature in the lance head (2) of the blowing lance, which is transferred from the molten metal onto the lance head (2) monitors with at least one temperature probe (21) integrated into the lance head (2) and is regulated by the water cooling and/or the influx of oxygen and/or the addition of aggregates and/or the distance of the lance head (2) from the surface of the molten metal bath.
2. The procedure in accordance with claim 1, characterized by the fact that for regulation the relationship between damage to the front end of the lance head (2) and serviceable life as well as the temperature curve dependent on serviceable life are taken into consideration as compensating quantities.
3. Water-cooling, for an oxygen blowing lance consisting of a shafted lance body (1) and a lance head (2) with the oxygen supply line (15) running through the lance body (1) to blowing nozzles (3 and 4) distributed in the lance head (2) and through the lance body (1) tip to the cooling chambers (5 - 10) in the lance head (2), off center, inlet and outlet channels (16 and 17) for the cooling water, in particular for use in a procedure in accordance with I or 2, characterized by the fact that at least one temperature probe (21) is integrated in the lance head (2) behind the front end of the lance head (11a) and between the cooling chambers (5 - 10). The signal lines (26) of the temperature probe run through the lance body (1).
4. A water-cooled oxygen blowing lance in accordance with claim 3 characterized by the fact that the temperature probe (21) is centered on the central axis of the lance body.
5. A water-cooled oxygen blowing lance in accordance with claims 3 or 4 characterized by the signal lines (26) being installed in a central protective pipe (27).
6. A water-cooled oxygen blowing lance in accordance with claim 5 characterized by the fact that the oxygen supply line (15) is in the middle of the lance body (1) and is surrounded by inlet and outlet channels (16 and 17) for the cool water formed as coaxial ring conduits, where the outlet conduit (17) is the outermost ring conduit and the inlet conduit is the most centered ring conduit.
7. A water-cooled oxygen blowing lance in accordance with claims 3 through 6 characterized by the fact that the temperature probe (21) is plugged into a bore hole (20) of a central strut (11) using a disconnectable adapter (22) that is mounted on the inside of the lance head (2).
8. A water-cooled oxygen blowing lance in accordance with claim 7 characterized by the fact that the temperature probe (21) is held in contact with the floor of the bore hole (20) using a spring (23) secured in an adapter (22) so that the temperature probe (21) can conduct heat.
9. A water-cooled oxygen blowing lance in accordance with claims 7 or 8 characterized by the fact that the protective pipe (27) overlaps the adapter (22) and seals telescopically.
10. A water-cooled oxygen blowing lance in accordance with one of the claims 3 through 8 characterized by the fact that coaxial fittings (2b, 2c and 2d) are attached to the cooling chambers (5 - 10) of the lance head (2) for the continuing oxygen supply line (15) and the continuing inlet and outlet channels (16 and 17) for cool water.
CA002388397A 1999-10-06 2000-10-06 Process for the metallurgical treatment of molten steel in a converter with oxygen top blown onto the molten steel and an oxygen blowing lance Abandoned CA2388397A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19948187A DE19948187C2 (en) 1999-10-06 1999-10-06 Process for the metallurgical treatment of a molten steel in a converter with oxygen blown onto the molten steel and oxygen blowing lance
PCT/US2000/028077 WO2002031212A1 (en) 1999-10-06 2000-10-06 Process for the metallurgical treatment of molten steel in a converter with oxygen top blown
DE19948187.3 2000-10-06

Publications (1)

Publication Number Publication Date
CA2388397A1 true CA2388397A1 (en) 2002-04-18

Family

ID=7924730

Family Applications (1)

Application Number Title Priority Date Filing Date
CA002388397A Abandoned CA2388397A1 (en) 1999-10-06 2000-10-06 Process for the metallurgical treatment of molten steel in a converter with oxygen top blown onto the molten steel and an oxygen blowing lance

Country Status (6)

Country Link
EP (1) EP1315841B1 (en)
AT (1) ATE294244T1 (en)
AU (1) AU2001210785A1 (en)
CA (1) CA2388397A1 (en)
DE (2) DE19948187C2 (en)
WO (1) WO2002031212A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3687666A4 (en) * 2018-08-17 2020-08-26 Berry Metal Company Controlling operation and position of a lance and nozzle assembly in a molten metal bath in a vessel

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10253463A1 (en) * 2002-11-16 2004-06-03 Gecon Engineering Gmbh Method and device for cooling blowing lances
US7402274B2 (en) * 2005-12-07 2008-07-22 Berry Metal Company Metal making lance slag detection system
DE202010017729U1 (en) * 2010-02-08 2012-07-27 Siemens Aktiengesellschaft Device for detecting at least one measured variable on an oven, and oven
UA113614C2 (en) * 2013-02-14 2017-02-27 METHOD OF OPERATION OF OXYGEN PRODUCTION COMPANY IN METALLURGICAL CAPACITY AND MEASUREMENT SYSTEM FOR DETERMINATION OF USED DURING SIGNIFICANCE
EP3117167B1 (en) * 2014-03-14 2017-12-27 Berry Metal Company Metal making lance with spring-loaded thermocouple or camera in lance tip

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Publication number Priority date Publication date Assignee Title
DE1433461B2 (en) * 1964-12-30 1972-02-10 Fried. Krupp Gmbh, 4300 Essen PROCESS AND DEVICE FOR MONITORING AND CONTROLLING THE REACTION PROCESS IN THE OXYGEN INFLATION PROCESS
US3574598A (en) * 1967-08-18 1971-04-13 Bethlehem Steel Corp Method for controlling basic oxygen steelmaking
US4106756A (en) * 1976-11-01 1978-08-15 Pullman Berry Company Oxygen lance and sensing adapter arrangement
US4474361A (en) * 1980-07-30 1984-10-02 Nippon Steel Corporation Oxygen-blown steelmaking furnace
US4732607A (en) * 1985-11-26 1988-03-22 Sumitomo Metal Industries, Ltd. Method of controlling the stirring strength and flow rate of a jet of gas blown through a lance onto a molten metal surface
DE3543836A1 (en) * 1985-12-12 1987-06-19 Clemens Karl Heinz Twin blowing lance installation for metallurgical treatments, with integral measuring lance installation
JPS62278217A (en) * 1986-05-27 1987-12-03 Nippon Steel Corp Lance inlaying thermocouple for controlling slag level
JPH03197612A (en) * 1989-12-25 1991-08-29 Kawasaki Steel Corp Method for refining molten metal

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3687666A4 (en) * 2018-08-17 2020-08-26 Berry Metal Company Controlling operation and position of a lance and nozzle assembly in a molten metal bath in a vessel

Also Published As

Publication number Publication date
DE19948187C2 (en) 2001-08-09
AU2001210785A1 (en) 2002-04-22
EP1315841B1 (en) 2005-04-27
ATE294244T1 (en) 2005-05-15
DE60019815D1 (en) 2005-06-02
EP1315841A4 (en) 2004-06-30
EP1315841A1 (en) 2003-06-04
WO2002031212A1 (en) 2002-04-18
DE19948187A1 (en) 2001-05-10

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Effective date: 20071009