US3900311A - Conversion of pig iron into steel - Google Patents

Conversion of pig iron into steel Download PDF

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Publication number
US3900311A
US3900311A US303357A US30335772A US3900311A US 3900311 A US3900311 A US 3900311A US 303357 A US303357 A US 303357A US 30335772 A US30335772 A US 30335772A US 3900311 A US3900311 A US 3900311A
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converter
tuyere
axis
oxygen
slag
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US303357A
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Paul Emile Nilles
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Centre de Recherches Metallurgiques CRM ASBL
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Centre de Recherches Metallurgiques CRM ASBL
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/32—Blowing from above

Definitions

  • the axis of the tuyere is inclined towards the bottom of the converter so that the injected oxygen creates rotational movement in the molten metal so as to better distribute the oxygen throughout the melt and control the decarbonization of the converter.
  • the tuyere in the side wall is mounted at the level of the zone occupied by the slag.
  • the present invention relates to a refining process for the conversion of pig iron into steel.
  • the present invention provides a refining process in which, by means of one or more tuyeres comprising two coaxial tubes and located in the wall ofa converter, above the upper level of the hot metal, technically pure oxygen is injected into the metal bath through the central tube of the tuyeres and then a liquid and/or gaseous protective fluid is injected through the peripheral conduit of the tuyeres, the tuyeres being inclined towards the bottom of the converter.
  • the oxygen and the protective fluid may advantageously be injected through one or more such tuyeres in the wall of the converter at the level of the zone occupied by the slag, which enables the appearance of the reactive character of the slag to be accelerated.
  • the present process has the important advantage of allowing an easy distribution of the oxygen between the metal and the slag and consequently the control of thc dccarburization rate; furthermore, inclination of the tuyere enables wear of the refractories in the side wall opposite the tuyere to be avoided.
  • the diameter of the tuyere as well as the rate of flow of oxygen and protective fluid are preferably arranged to he adjustable and controllable, in order to accelerate the refining of the pig iron. particularly by helping to rapidly form a fluid reactive slag.
  • Each injection may advantageously be effected along an axis inclined towards the bottom of the converter and located in a diametrical plane of the converter, which results in producing in the metal a double rotational movement at one and the same time in a vertical plane and in a horizontal plane. which produces excellent mixing of the hot metal and thorough decarburization.
  • the injection can be carried out by means of a single tuyere, directed towards the bottom of the converter, the direction of the jet of oxygen not however passing through the axis of the converter.
  • the injection may be carried out simultaneously on different levels, namely above the level of the slag and into the slag, their direction not passing through the longitudinal axis of the converter.
  • the rotational movements imparted to the slag and metal are judiciously controlled by the arrangement of the tuyeres in the wall of the converter.
  • the tuyeres can be arranged to be orientated in the same sense in relation to the axis of the converter or in the opposed sense, whether side by side or spaced, in the wall of the converter all around its periphery.
  • pulvcrulent materials preferably slagging materials, such as for example lime
  • slagging materials such as for example lime
  • the protective fluid is advantageously composed of a gaseous or liquid hydrocarbon.
  • FIG. I is a vertical cross-section of a converter according to the instant invention.
  • FIGS. 2 and 3 are simplified [horizontal cross-sections of the outside wall of the converter showing two embodiments of the invention.
  • tuyere 1 has an inner tube 2 for the blowing of oxygen and this tube 2 is surrounded by a concentric tube 3 through which a cooling medium is injected.
  • This tuyere I is inserted in a side wall 4 of a converter 5 and the longitudinal axis 6 of this tuyere l is inclined towards the converter bottom with the jet of oxygen directly impinging on slag 7, molten metal 8 being underneath.
  • the angle of inclination of the tuyere is a and is the angle made by the longitudinal axis 6 of the tuyere with a horizontal plane 9 passing through a point 10 where this lontitudinal axis 6 enters the converter, when the converter is stationary with its longitudinal axis 12 in vertical position.
  • FIG. 2 shows the tuyere I with its longitudinal axis 6 inclined towards the bottom of the converter and located in the diametrical plane of the converter. Such a location results in producing in the metal a double rotational movement (arrows l3 and I4) at one and the same time. This movement also takes place in a vertical plane and in a horizontal plane because of the inclination a of the tuyere towards the metallic bath.
  • the jet of oxygen with cooling medium impinges the molten metal and produces two force components: one vertical (arrow 15. FIG. I) and one horizontal (arrow I6, FIG. 1).
  • FIG. 3 shows the tuyere I having a longitudinal axis 6 which does not intersect longitudinal axis I2 of the converter.
  • the direction of this axis 6 many he defined by a distance 17 between axis 6 and axis 12. Such a direction enables a rotational movement (arrow 18) in the metal and in the slag to be achieved.
  • a differential rotational movement between the metal and the slag may be achieved by judiciously selecting the speeds and rates of flow to different injection tuyercs.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

A refining process for converting pig iron into steel wherein at least one tuyere is mounted in the side wall on the converter and the tuyere has an inner conduit and an outer conduit. Substantially pure oxygen is injected through the inner conduit and a protective fluid is injected through the outer conduit. The axis of the tuyere is inclined towards the bottom of the converter so that the injected oxygen creates rotational movement in the molten metal so as to better distribute the oxygen throughout the melt and control the decarbonization of the converter. The tuyere in the side wall is mounted at the level of the zone occupied by the slag.

Description

United States Patent 11 1 Nilles 1451 Aug. 19, 1975 1 CONVERSION OF PIG IRON INTO STEEL [75] Inventor: Paul Emile Nilles, Embourg Belgium [22] Filed: Nov. 3, 1972 [21] Appl. No: 303,357
3.079249 2/1963 Moustier 75 60 3,330,645 7/1967 M0ustier..... 75/60 5,556,773 1/1971 Grenfell 75/52 3706549 12/1972 Knuppel 75/60 Primary EtuminerL. Dewayne Rutledge Assistant ExaminerPeter D. Rosenberg Attorney, Agent, or Firm-Holman & Stern 5 7 ABSTRACT A refining process for converting pig iron into steel wherein at least one tuyere is mounted in the side wall on the converter and the tuyere has an inner conduit and an outer conduit. Substantially pure oxygen is injected through the inner conduit and a protective fluid is injected through the outer conduit. The axis of the tuyere is inclined towards the bottom of the converter so that the injected oxygen creates rotational movement in the molten metal so as to better distribute the oxygen throughout the melt and control the decarbonization of the converter. The tuyere in the side wall is mounted at the level of the zone occupied by the slag.
6 Claims, 3 Drawing Figures CONVERSION OF PIG IRON INTO STEEL BACKGROUND OF THE INVENTION The present invention relates to a refining process for the conversion of pig iron into steel.
It is known that the problem of the life of the bottom of an oxygen-blown converter has been solved by the use. for the injection of industrially pure oxygen beneath the surface of the metallic bath, of tuyeres comprising two concentric conduits located either in the bottom or in the side wall beneath the surface of the metallic bath, the central conduit serving for the blowing-in of pure oxygen, the peripheral conduit serving SUMMARY OF THE INVENTION The present invention provides a refining process in which, by means of one or more tuyeres comprising two coaxial tubes and located in the wall ofa converter, above the upper level of the hot metal, technically pure oxygen is injected into the metal bath through the central tube of the tuyeres and then a liquid and/or gaseous protective fluid is injected through the peripheral conduit of the tuyeres, the tuyeres being inclined towards the bottom of the converter.
The oxygen and the protective fluid may advantageously be injected through one or more such tuyeres in the wall of the converter at the level of the zone occupied by the slag, which enables the appearance of the reactive character of the slag to be accelerated.
Owing to the possibility of placing the oxygen directly in contact with the slag and metal, the present process has the important advantage of allowing an easy distribution of the oxygen between the metal and the slag and consequently the control of thc dccarburization rate; furthermore, inclination of the tuyere enables wear of the refractories in the side wall opposite the tuyere to be avoided.
It has been confirmed that with the present process it is also possible to avoid the formation of metallic heads on the periphery of the tuyeres within the converter; such heads constitute a handicap to the processes in which the injection of oxygen is made beneath the surface of the hot metal.
The diameter of the tuyere as well as the rate of flow of oxygen and protective fluid are preferably arranged to he adjustable and controllable, in order to accelerate the refining of the pig iron. particularly by helping to rapidly form a fluid reactive slag.
Each injection may advantageously be effected along an axis inclined towards the bottom of the converter and located in a diametrical plane of the converter, which results in producing in the metal a double rotational movement at one and the same time in a vertical plane and in a horizontal plane. which produces excellent mixing of the hot metal and thorough decarburization.
The injection can be carried out by means of a single tuyere, directed towards the bottom of the converter, the direction of the jet of oxygen not however passing through the axis of the converter.
The injection may be carried out simultaneously on different levels, namely above the level of the slag and into the slag, their direction not passing through the longitudinal axis of the converter. By judiciously selecting the speeds and rates of flow to the different injection tuyeres, a differential rotational movement between the metal and the slag is achieved, which enables the physico-chemical exchanges at the slag/metal interface to be increased, and therefore accelerates decarburization.
The rotational movements imparted to the slag and metal are judiciously controlled by the arrangement of the tuyeres in the wall of the converter. For this purpose, according to requirements, the tuyeres can be arranged to be orientated in the same sense in relation to the axis of the converter or in the opposed sense, whether side by side or spaced, in the wall of the converter all around its periphery.
It is within the scope of the present invention to place one or several pulvcrulent materials, preferably slagging materials, such as for example lime, in suspension in the oxygen.
The protective fluid is advantageously composed of a gaseous or liquid hydrocarbon.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a vertical cross-section of a converter according to the instant invention; and
FIGS. 2 and 3 are simplified [horizontal cross-sections of the outside wall of the converter showing two embodiments of the invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS According to FIG. I, tuyere 1 has an inner tube 2 for the blowing of oxygen and this tube 2 is surrounded by a concentric tube 3 through which a cooling medium is injected. This tuyere I is inserted in a side wall 4 of a converter 5 and the longitudinal axis 6 of this tuyere l is inclined towards the converter bottom with the jet of oxygen directly impinging on slag 7, molten metal 8 being underneath.
The angle of inclination of the tuyere is a and is the angle made by the longitudinal axis 6 of the tuyere with a horizontal plane 9 passing through a point 10 where this lontitudinal axis 6 enters the converter, when the converter is stationary with its longitudinal axis 12 in vertical position.
FIG. 2 shows the tuyere I with its longitudinal axis 6 inclined towards the bottom of the converter and located in the diametrical plane of the converter. Such a location results in producing in the metal a double rotational movement (arrows l3 and I4) at one and the same time. This movement also takes place in a vertical plane and in a horizontal plane because of the inclination a of the tuyere towards the metallic bath. The jet of oxygen with cooling medium impinges the molten metal and produces two force components: one vertical (arrow 15. FIG. I) and one horizontal (arrow I6, FIG. 1).
FIG. 3 shows the tuyere I having a longitudinal axis 6 which does not intersect longitudinal axis I2 of the converter. The direction of this axis 6 many he defined by a distance 17 between axis 6 and axis 12. Such a direction enables a rotational movement (arrow 18) in the metal and in the slag to be achieved. In the case of several tuyeres located at different levels, a differential rotational movement between the metal and the slag may be achieved by judiciously selecting the speeds and rates of flow to different injection tuyercs.
I claim:
1. A refining process for the conversion of pig iron into steel in a converter wherein the molten metal is ag itated by blown oxygen so as to better distribute the oxygen throughout the melt and control the decarburization, the converter having a bottom, a side wall, and at least one tuyere in the side wall, the tuyere comprising an inner conduit and an outer conduit surrounding the inner conduit, the process including the steps of injecting substantially pure oxygen through said inner conduit onto the molten metal in the converter, and in jecting a protective fluid through the outer conduit, the tuyere opening into the converter through the sidewall at the level of the zone occupied by slag and the axis of the tuyere being inclined towards the converter bottom to create rotational movement of the molten metal.
2. A process as claimed in claim 1, in which the axis of the tuyere is directed along a line contained in a diametrical plane of the converter.
3. A process as claimed in claim 1, in which only one tuyere is used, the axis of the tuyere being directed towards the converter bottom along a line which does not intersect the converter axis.
4. A process as claimed in claim 1, in which two tuyeres are used, one opening into the converter above the slag layer and the other opening into the slag layer, the axis of each tuyere being directed along a line which does not inersect the axis of rotation of the converter, the speed and flow rate of the materials injected through the tuyere being such that the molten metal and the slag rotate at different speeds.
5. The process as claimed in claim 1, in which pow dery material is in suspension in the injected oxygen.
6. The process as claimed in claim 1, in which the protective fluid is a hydrocarbon.

Claims (6)

1. A REFINING PROCESS FOR THE CONVERSION OF PIG IRON INTO STEEL IN A CONVERTER WHEREIN THE MOLTEN METAL IS AGITATED BY BLOWN OXYGEN SO AS TO BETTER DISTRIBUTE THE OXYGEN THROUGHOUT THE MELT AND CONTROL THE DECARBURIZATION, THE CONVERTER HAVING A BOTTOM, A SIDE WALL, AND AT LEAST ONE TUYERE IN THE SIDE WALL, THE TUYERE COMPRISING AN INNER CONDUIT AND AN OUTER CONDUIT SURR OR INJECTING SUBSTANTIALLY PURE OXYGEN THROUGH SAID INNER CONDUIT ONTO THE MOLTEN METAL IN THE CONVERTER, AND INJECTING A PROTECTIVE FLUID THROUGH THE OUTER CONDUIT, TE TUYERE OPENING INTO THE CONVERTER THROUGH THE SIDEWALL AT THE LEVEL OF THE ZONE OCCUPIED BY SLAG AN THE AXIS OF THE TUYERE BEING INCLINED TOWARDS THE CONVERTER BOTTOM TO CREATE ROTATIONAL MOVEMENT OF THE MOLTEN METAL.
2. A process as claimed in claim 1, in which the axis of the tuyere is directed along a line contained in a diametrical plane of the converter.
3. A process as claimed in claim 1, in which only one tuyere is used, the axis of the tuyere being directed towards the converter bottom along a line which does not intersect the converter axis.
4. A process as claimed in claim 1, in which two tuyeres are used, one opening into the converter above the slag layer and the other opening into the slag layer, the axis of each tuyere being directed along a line which does not inersect the axis of rotation of the converter, the speed and flow rate of the materials injected through the tuyere being such that the molten metal and the slag rotate at different speeds.
5. The process as claimed in claim 1, in which powdery material is in suspension in the injected oxygen.
6. The process as claimed in claim 1, in which the protective fluid is a hydrocarbon.
US303357A 1971-11-03 1972-11-03 Conversion of pig iron into steel Expired - Lifetime US3900311A (en)

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BE774886A BE774886A (en) 1971-11-03 1971-11-03 PROCESS FOR THE CONVERSION OF CAST IRON INTO STEEL.

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BE (1) BE774886A (en)
DE (1) DE2253272A1 (en)
FR (1) FR2158573B1 (en)
GB (1) GB1355605A (en)
NL (1) NL7214657A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4065298A (en) * 1974-12-28 1977-12-27 Nippon Kokan Kabushiki Kaisha Steel making process by oxygen top-blown converter
US4195985A (en) * 1977-12-10 1980-04-01 Eisenwerk-Gesellschaft Maximilianshutte Mbh. Method of improvement of the heat-balance in the refining of steel
US4518417A (en) * 1982-01-19 1985-05-21 Voest-Alpine Aktiengesellschaft Method of, and arrangement for, reducing oxide-containing fine-particle ores
US4639269A (en) * 1984-12-10 1987-01-27 Klockner-Humboldt-Deutz Aktiengesellschaft Method and apparatus for the reducing treatment of molten metals and/or slags thereof

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1793153A (en) * 1927-07-20 1931-02-17 Electro Metallurg Co Process of making rustless iron alloys
US2855293A (en) * 1955-03-21 1958-10-07 Air Liquide Method and apparatus for treating molten metal with oxygen
US2918365A (en) * 1953-08-10 1959-12-22 Yawata Seitetsu K K Method for controlling compositions of molten pig iron and slag in a blast furnace
US3015554A (en) * 1957-04-18 1962-01-02 Rummel Roman Method and device for carrying out metallurgical processes, particularly air refining processes
US3079249A (en) * 1959-02-27 1963-02-26 Air Liquide Method for refining iron using technically pure oygen
US3330645A (en) * 1962-08-07 1967-07-11 Air Liquide Method and article for the injection of fluids into hot molten metal
US3556773A (en) * 1966-09-26 1971-01-19 Steel Co Of Wales Ltd Refining of metals
US3706549A (en) * 1968-02-24 1972-12-19 Maximilianshuette Eisenwerk Method for refining pig-iron into steel

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1194741A (en) * 1957-04-18 1959-11-12 Method and device for performing metallurgical operations, in particular by wind refining
FR1231179A (en) * 1959-04-09 1960-09-27 Process and device for refining cast iron

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1793153A (en) * 1927-07-20 1931-02-17 Electro Metallurg Co Process of making rustless iron alloys
US2918365A (en) * 1953-08-10 1959-12-22 Yawata Seitetsu K K Method for controlling compositions of molten pig iron and slag in a blast furnace
US2855293A (en) * 1955-03-21 1958-10-07 Air Liquide Method and apparatus for treating molten metal with oxygen
US3015554A (en) * 1957-04-18 1962-01-02 Rummel Roman Method and device for carrying out metallurgical processes, particularly air refining processes
US3079249A (en) * 1959-02-27 1963-02-26 Air Liquide Method for refining iron using technically pure oygen
US3330645A (en) * 1962-08-07 1967-07-11 Air Liquide Method and article for the injection of fluids into hot molten metal
US3556773A (en) * 1966-09-26 1971-01-19 Steel Co Of Wales Ltd Refining of metals
US3706549A (en) * 1968-02-24 1972-12-19 Maximilianshuette Eisenwerk Method for refining pig-iron into steel

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4065298A (en) * 1974-12-28 1977-12-27 Nippon Kokan Kabushiki Kaisha Steel making process by oxygen top-blown converter
US4195985A (en) * 1977-12-10 1980-04-01 Eisenwerk-Gesellschaft Maximilianshutte Mbh. Method of improvement of the heat-balance in the refining of steel
US4518417A (en) * 1982-01-19 1985-05-21 Voest-Alpine Aktiengesellschaft Method of, and arrangement for, reducing oxide-containing fine-particle ores
US4639269A (en) * 1984-12-10 1987-01-27 Klockner-Humboldt-Deutz Aktiengesellschaft Method and apparatus for the reducing treatment of molten metals and/or slags thereof

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GB1355605A (en) 1974-06-05
BE774886A (en) 1972-05-03
DE2253272A1 (en) 1973-05-10
NL7214657A (en) 1973-05-07
FR2158573B1 (en) 1977-01-14
FR2158573A1 (en) 1973-06-15
JPS4853917A (en) 1973-07-28

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