US3725041A - Deoxidizing metal - Google Patents

Deoxidizing metal Download PDF

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US3725041A
US3725041A US00075738A US3725041DA US3725041A US 3725041 A US3725041 A US 3725041A US 00075738 A US00075738 A US 00075738A US 3725041D A US3725041D A US 3725041DA US 3725041 A US3725041 A US 3725041A
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carbon
hydrocarbon
deoxidizer
vessel
diluent gas
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S Ramachandran
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Allegheny Ludlum Corp
Pittsburgh National Bank
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Allegheny Ludlum Industries Inc
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
    • 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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/06—Deoxidising, e.g. killing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/143—Reduction of greenhouse gas [GHG] emissions of methane [CH4]

Definitions

  • the present invention relates to a method of deoxidizing molten metal and more particularly to a method of deoxidizing molten metal while maintaining the carbon content of the metal at a level about equal to or lower than the level prior to deoxidizing.
  • a lowering of the partial pressure of carbon monoxide changes equilibrium relationships and shifts the attainable end point carbon to lower levels without necessitating excessive oxidation of metallic components and, thereby, frees carbon to combine with oxygen within the melt.
  • Reduction in the partial pressure can be accomplished by reducing the pressure in the vessel and/ or by introducing argon into the vessel.
  • This third method does not measure up to theoretical expectations as the carbon-oxygen reaction fails to proceed to completion. From a thermodynamic point of view, the system acts as if it were under a higher pressure.
  • the present invention provides a method which eti'ectively deoxidizes a melt while controlling the carbon content at a level about equal to or lower than that which was present prior to deoxidizing. It employs at least one hydrocarbon as a deoxidizer and at least one diluent gas.
  • the diluent gas enables the processor to use small amounts of hydrocarbon deoxidizer, thereby precluding excessive injection of carbon into the melt, while maintaining a gaseous injection rate which is sufiicient to insure adequate mixing between the hydrocarbon deoxidizer and the melt.
  • the hydrocarbon deoxidizer input rate can be lowered without reducing the rate of oxygen reaction with carbon, by introducing a diluent gas with the hydrocarbon deoxidizer.
  • the present invention comprises the steps of introducing hydrocarbon deoxidizer and diluent gas into a vessel containing molten metal, determining the eiiect of the hydrocarbon deoxidizer and diluent gas upon the carbon content of the metal and controlling the proportion of hydrocarbon deoxidizer to diluent gas so that the average rate of carbon leaving the vessel is about equal to or greater than the average rate of carbon being introduced into the vessel.
  • the invention embraces the use of one or more hydrocarbon deoxidizers chosen from a wide spectrum of gase- (ms and liquid hydrocarbons and hydrocarbon containing substances as well as the use of one or more diluent gases chosen from a wide spectrum of diluent gases.
  • hydrocarbons and hydrocarbon containing substances are methane, ethane, propane, ethylene, water gas and natural gas.
  • Illustrative diluent gases are argon, nitrogen, hydrogen and carbon monoxide.
  • Liquid hydrocarbons and hydrocarbon containing substances require the additional step of atomizing the liquid into the diluent gas stream.
  • the hydrocarbon deoxidizer and diluent gas can be blown into or blown onto the top of the melt.
  • the efiiciency at which carbon and oxygen combined tells a processor what the proportion of hydrocarbon deoxidizer to diluent gas should be for subsequent heats, of similar chemistry, which are to be deoxidized under similar conditions, e.g., similar gaseous injection rates.
  • a heat deoxidized with hydrocarbon deoxidizer and 20% diluent gas and having a 50% carbon-oxygen reaction etficiency indicates that subsequent heats should use 40% or less hydrocarbon deoxidizer and 60% or more diluent gas if the heats are of similar chemistry and are to be similarly deoxidized.
  • An alternative process for detemining the effect of the hydrocarbon deoxidizer overcomes the shortcoming of the above described procedure. It involves calculating the rate at which carbon is introduced to the vessel and the rate at which it leaves the vessel.
  • the carbon input rate can be calculated from the analysis and input rate of hydrocarbon deoxidizer and diluent gas.
  • the carbon output rate can be calculated from the output rate and analysis of the gases exiting the vessel (a monitoring system can be used to analyze the exiting gases).
  • the calculations enable a processor to control the carbon content of the melt by adjusting the rate at which carbon is introduced to the vessel.
  • the hydrocarbon deoxidizer and the diluent gas are injected into the vessel at an average gaseous injection rate of at least 20 cu. ft. per hour.
  • a preferred average gaseous injection rate is at least 30 cu. ft. per hour.
  • Lower injection rates are, however, embraced within this invention. A precise value cannot be set for the minimum rate as it fluctuates with process variables, such as the depth of the molten metal.
  • the invention can additionally encompass controlling of the final oxygen content. This entails knowledge of the oxygen content prior to or at some stage during deoxidation and calculating of the amount of oxygen leaving the system.
  • Oxygen in the melt can be measured by an EMF cell or by chemical analysis.
  • the amount of oxygen leaving the system can be calculated from an analysis of the gases exiting from the system and from the following equations:
  • the carbon input and input rate can be obtained from the following equations:
  • the carbon output and output rate can be obtained from the following equations:
  • a method of deoxidizing molten steel and controlling its final oxygen content while maintaining a carbon level about equal to or lower than the carbon level which Was present prior to deoxidizing which comprises the steps of: analyzing molten steel to determine its oxygen content; introducing hydrocarbon deoxidizer and diluent gas at an average injection rate of at least 20 cu. ft.
  • a method according to claim 1 wherein said introducing of hydrocarbon deoxidizer and diluent gas into 6 said vessel containing molten steel comprises the step of blowing hydrocarbon deoxidizer and diluent gas into said molten steel.
  • a method according to claim 1 wherein said introducing of hydrocarbon deoxidizer and diluent gas into said vessel containing molten steel comprises the step of blowing hydrocarbon deoxidizer and diluent gas onto said molten steel.
  • a method according to claim 1 wherein said determining of the efiect of said hydrocarbon deoxidizer and diluent gas upon the carbon content of said steel comprises the steps of: calculating the rate at which carbon is introduced into said vessel; and calculating the rate at which carbon leaves said vessel.
  • a method according to claim 5 including the step of analyzing the gases exiting from said vessel.
  • hydrocarbon deoxidizer is comprised of methane.
  • said diluent gas is comprised of argon.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

A METHOD OF DEOXIDIZING METAL WHILE MAINTAINING THE CARBON CONTENT OF THE METAL AT A LEVEL ABOUT EQUAL TO OR LOWER THAN THE LEVEL PRIOR TO DEOXIDIZING. IT COMPRISES THE STEPS OF INTRODUCING HYDROCARBON DEOXIDIZER AND DILUENT GAS INTO A VESSEL CONTAINING MOLTEN METAL, DETERMINING THE EFFECT OF THE HYDROCARBON DEOXIDIZER AND DILUENT GAS UPON THE CARBON CONTENT OF THE METAL AND CONTROLLING THE PROPORTION OF HYDROCARBON DEOXIDIZER TO DILUENT GAS SO THAT THE AVERAGE RATE OF CARBON LEAVING THE VESSEL IS ABOUT EQUAL TO OR GREATER THAN THE AVERAGE RATE OF CARBON BEING INTRODUCED INTO THE VESSEL.

Description

United States Patent 6 3,725,041 DEOXIDIZING METAL Sundaresan Ramachandran, Natrona Heights, Pa, as-
signor to Allegheny Ludlum Industries, Inc., Pittsburgh, Pa. No Drawing. Filed Sept. 25, 1970, Ser. No. 75,738 Int. Cl. C21c 7/06 US. CI. 75-60 10 Claims ABSTRACT on THE DISCLOSURE A method of deoxidizing metal while maintaining the carbon content of the metal at a level about equal to or lower than the level prior to deoxidizing. It comprises the steps of introducing hydrocarbon deoxidizer and dilucnt gas into a vessel containing molten metal, determining the effect of the hydrocarbon deoxidizer and diluent gas upon the carbon content of the metal and controlling the proportion of hydrocarbon deoxidizer to diluent gas so that the average rate of carbon leaving the vessel is about equal to or greater than the average rate of carbon being introduced into the vessel.
The present invention relates to a method of deoxidizing molten metal and more particularly to a method of deoxidizing molten metal while maintaining the carbon content of the metal at a level about equal to or lower than the level prior to deoxidizing.
Present day metal-making; e.g., steel-making, processes often involve a deoxidizing treatment. It is highly desirable to lower the oxygen content of a melt since oxygen dissolved in a melt can precipitate as non-metallic inclusions which adversely atfect the properties of the metal.
Various deoxidizing methods have been employed in the past. One method involves the use of highly reactive elements; e.g., silicon, titanium and/or aluminum, which combine with oxygen in the melt to form oxides that subsequently separate from the melt. Sufiicient time must, however, be provided for the oxides and melt to separate. A second method involves the mixing of -a predetermined quantity of carbon with the melt and a dynamic hydrogen atmosphere to control carbon boil. This method is elfective for lowering the oxygen content but often adversely afiects the desired low carbon content. It is disclosed in US. Pat. No. 3,188,198 which issued on June 8, 1965. A third method, particularly efiective for alloy steels with high carbon contents, involves the lowering of the partial pressure of carbon monoxide in the vessel. A lowering of the partial pressure of carbon monoxide changes equilibrium relationships and shifts the attainable end point carbon to lower levels without necessitating excessive oxidation of metallic components and, thereby, frees carbon to combine with oxygen within the melt. Reduction in the partial pressure can be accomplished by reducing the pressure in the vessel and/ or by introducing argon into the vessel. This third method, however, does not measure up to theoretical expectations as the carbon-oxygen reaction fails to proceed to completion. From a thermodynamic point of view, the system acts as if it were under a higher pressure.
Another prior art process of considerable interest is disclosed in an article entitled Deoxidation Techniques for Vacuum-Induction Melting by W. F. Moore. :It appeared on pages 918-921 in the December 1963 issue of the Journal of Metals. The process described therein employed natural gas which consisted of, by volume, 94.9% CH 3.2% C H 1.0% C H 0.1% C H 0.6% C 0.1% H 0 and 0.1% N +CO, to deoxidize a melt. Results from the process were promising with regard to the degree of deoxidizing but were unfortunately disappointing to processors who require both low carbon and oxygen contents in their steel. The natural gas injected ice an excess of carbon into the melt and thereby, raised its carbon content.
It would appear that the major shortcoming of the process described in the above referred to Journal of Metals article could be rectified by reducing the amount of natural gas injected into the melt. The most obvious manner of accomplishing this would be to simply reduce the natural gas input flow rate. This however, diminishes the mixing caused by the input of the gas which in turn reduces the degree of reaction between carbon that evolves from the gas and oxygen in the melt.
The present invention provides a method which eti'ectively deoxidizes a melt while controlling the carbon content at a level about equal to or lower than that which was present prior to deoxidizing. It employs at least one hydrocarbon as a deoxidizer and at least one diluent gas. The diluent gas enables the processor to use small amounts of hydrocarbon deoxidizer, thereby precluding excessive injection of carbon into the melt, while maintaining a gaseous injection rate which is sufiicient to insure adequate mixing between the hydrocarbon deoxidizer and the melt. Thus, the hydrocarbon deoxidizer input rate can be lowered without reducing the rate of oxygen reaction with carbon, by introducing a diluent gas with the hydrocarbon deoxidizer.
It is accordingly an object of this invention to provide a method of deoxidizing molten metal.
It is an additional object of this invention to provide a method of deoxidizing molten metal while maintaining the carbon content of the metal at a level about equal to or lower than the level prior to deoxidizing.
The present invention comprises the steps of introducing hydrocarbon deoxidizer and diluent gas into a vessel containing molten metal, determining the eiiect of the hydrocarbon deoxidizer and diluent gas upon the carbon content of the metal and controlling the proportion of hydrocarbon deoxidizer to diluent gas so that the average rate of carbon leaving the vessel is about equal to or greater than the average rate of carbon being introduced into the vessel.
The invention embraces the use of one or more hydrocarbon deoxidizers chosen from a wide spectrum of gase- (ms and liquid hydrocarbons and hydrocarbon containing substances as well as the use of one or more diluent gases chosen from a wide spectrum of diluent gases. Illustrative hydrocarbons and hydrocarbon containing substances are methane, ethane, propane, ethylene, water gas and natural gas. Illustrative diluent gases are argon, nitrogen, hydrogen and carbon monoxide. Liquid hydrocarbons and hydrocarbon containing substances require the additional step of atomizing the liquid into the diluent gas stream. The hydrocarbon deoxidizer and diluent gas can be blown into or blown onto the top of the melt.
The elfect of the hydrocarbon deoxidizer upon the carbon content of a melt can be determined from the initial and final melt analysis of a previously deoxidized melt. A comparison of the initial and final analysis along with the input rate and analysis of the hydrocarbon deoxidizer and/or diluent gas (diluent gas is not necessary here as this is not necessarily a heat requiring a low carbon level) introduced into the vessel sets forth the information necessary to determine the efficiency at which carbon, from the deoxidizer, combined with oxygen. The efiiciency at which carbon and oxygen combined tells a processor what the proportion of hydrocarbon deoxidizer to diluent gas should be for subsequent heats, of similar chemistry, which are to be deoxidized under similar conditions, e.g., similar gaseous injection rates. For example, a heat deoxidized with hydrocarbon deoxidizer and 20% diluent gas and having a 50% carbon-oxygen reaction etficiency indicates that subsequent heats should use 40% or less hydrocarbon deoxidizer and 60% or more diluent gas if the heats are of similar chemistry and are to be similarly deoxidized.
Although the above described procedure for determining the effect of the hydrocarbon deoxidizer is far better than adequate, it does have a shortcoming. The end-point control may not be too precise due to heat variations in analysis, temperature and efficiency of gas blowing.
An alternative process for detemining the effect of the hydrocarbon deoxidizer overcomes the shortcoming of the above described procedure. It involves calculating the rate at which carbon is introduced to the vessel and the rate at which it leaves the vessel. The carbon input rate can be calculated from the analysis and input rate of hydrocarbon deoxidizer and diluent gas. The carbon output rate can be calculated from the output rate and analysis of the gases exiting the vessel (a monitoring system can be used to analyze the exiting gases). The calculations enable a processor to control the carbon content of the melt by adjusting the rate at which carbon is introduced to the vessel.
The following paragraphs are exemplary of the type of reactions which occur during the deoxidizing method of this invention and of a method for calculating both the carbon input and output. Methane, CH has been chosen as the hydrocarbon deoxidizer for purposes of illustration.
The major reactions which occur during deoxidation with methane are:
4 )+Q= H Z CH (gas)+MO=E-]CO (gasH-ZH (gas) leaving the system No numerical value can be set for the ratio of hydrocarbon deoxidizer to diluent gas as it can change throughout the deoxidizing treatment. At times, it is even desirable to complete the final stages of deoxidation with an inert gas and without any hydrocarbon deoxidizer. The inert gas will lower the partial pressure of carbon monoxide, change equilibrium relationships and shift the attainable end point carbon to lower levels without necessitating excessive oxidation of metallic components, thereby freeing carbon to combine with oxygen within the melt. It will additionally cause a mixing of the melt which will promote the carbon-oxygen reaction. As a general rule the hydrocarbon deoxidizer and the diluent gas are injected into the vessel at an average gaseous injection rate of at least 20 cu. ft. per hour. A preferred average gaseous injection rate is at least 30 cu. ft. per hour. Lower injection rates are, however, embraced within this invention. A precise value cannot be set for the minimum rate as it fluctuates with process variables, such as the depth of the molten metal.
The invention can additionally encompass controlling of the final oxygen content. This entails knowledge of the oxygen content prior to or at some stage during deoxidation and calculating of the amount of oxygen leaving the system. Oxygen in the melt can be measured by an EMF cell or by chemical analysis. The amount of oxygen leaving the system can be calculated from an analysis of the gases exiting from the system and from the following equations:
t t 1 ft f atomic wt.
0 0 Pounds of oxygen g H O X 1 mole xygen (lbs) 2 2 360 cu. ft. average leaving the system molecular The deoxidizing reactions can be carried out at pressures which are at, below or above atmospheric pressure.
The reaction which leads to carburization of the bath is:
An additional carburization reaction which can occur to an intolerable degree when there is an excessive amount of hydrocarbon deoxidizer is:
CH; (gas)=C+2H (gas) The hydrocarbon deoxidizer cracks and deposits carbon (soot) in the cooler parts of the vessel.
The carbon input and input rate can be obtained from the following equations:
total cu. ft. of methane introduced into the vessel Rate carbon is being pounds of carbon introduced into =introduced into the vessel the vessel Pounds of carbon introduced into the vessel 1 mole X 360 cu. ft.
:time
The carbon output and output rate can be obtained from the following equations:
total cu. ft. of
g f gi gi CH c0 and 1 mole at CO leaving the 360 cu. ft. the vessel vessel Rate of carbon pounds of earbon leaving the vesse1 leavin g the vessel wt. of gases leaving the vessel rate of oxygen pounds of oxygen +t' leaving the system leaving the system [me atomic wt. of X carbon (lbs) 1 mole atomic wt. of X carbon (lbs) 1 mole TABLE I Analysis (p.p.m.)
C O N TABLE II Analysis (p.p.m.)
C O N A study of the results reveals that the carbon content of heats A and B increased despite the fact that their oxygen contents decreased whereas the carbon and oxygen contents of heat C substantially decreased. Heats A and B were not deoxidized in accordance with this invention as they involved the injection of pure methane into the melt. On the other hand, heat C was deoxidized in accordance with the method of this invention as it involved the injection of methane and diluent gas.
It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein in connection with specific examples thereof will suggest various other modifications and applications of the same. It is accordingly desired that in construing the breadth of the appended claims they shall not be limited to the specific examples of the invention described herein.
I claim:
1. A method of deoxidizing molten steel and controlling its final oxygen content while maintaining a carbon level about equal to or lower than the carbon level which Was present prior to deoxidizing, which comprises the steps of: analyzing molten steel to determine its oxygen content; introducing hydrocarbon deoxidizer and diluent gas at an average injection rate of at least 20 cu. ft. per hour into a vessel containing molten steel at a subatmospheric pressure, said hydrocarbon deoxidizer reacting with oxygen within said steel to form gaseous carbon compounds which exit from said vessel; determining the efiect of the hydrocarbon deoxidizer and diluent gas upon the carbon content of the steel; controlling the proportion of hydrocarbon deoxidizer to diluent gas so that the average rate of carbon leaving said vessel is about equal to or greater than the average rate of carbon being introduced into said vessel; and discontinuing said introduction of hydrocarbon deoxidizer and diluent gas into said vessel after a predetermined amount of oxygen has been removed from said steel.
2. A method according to claim 1 wherein said introducing of hydrocarbon deoxidizer and diluent gas into 6 said vessel containing molten steel comprises the step of blowing hydrocarbon deoxidizer and diluent gas into said molten steel.
3. A method according to claim 1 wherein said introducing of hydrocarbon deoxidizer and diluent gas into said vessel containing molten steel comprises the step of blowing hydrocarbon deoxidizer and diluent gas onto said molten steel.
4. A method according to claim 1 wherein said molten steel is a second melt and wherein said determining of the eifect of said hydrocarbon deoxidizer and diluent gas upon the carbon content of said melt, comprises the steps of: analyzing a first melt contained within a vessel to determine its carbon content; deoxidizing said first melt with hydrocarbon deoxidizer; calculating the amount of carbon introduced into said vessel containing said first melt; analyzing said deoxidized first melt to determine its carbon content; and calculating the efliciency of said introduced carbon in deoxidizing said first melt.
5. A method according to claim 1 wherein said determining of the efiect of said hydrocarbon deoxidizer and diluent gas upon the carbon content of said steel, comprises the steps of: calculating the rate at which carbon is introduced into said vessel; and calculating the rate at which carbon leaves said vessel.
6. A method according to claim 5 including the step of analyzing the gases exiting from said vessel.
7. A method according to claim 1 wherein said average injection rate is at least 30 cu. ft. per hour.
8. A method according to claim 1 wherein said hydrocarbon deoxidizer is comprised of methane.
9. A method according to claim 8 wherein said diluent gas is comprised of argon.
10. A method according to claim 1 wherein said hydrocarbon deoxidizer is a liquid and including the steps of atomizing and mixing said liquid hydrocarbon deoxidizer into said diluent gas.
References Cited UNITED STATES PATENTS 2,991,684 7/1961 Wever et al. -23 X 3,403,090 9/1968 Tajiri et al. 204- S 3,529,955 9/ 1970 Themelis 75-60 3,623,863 11/ 1971 Henderson et al. 75-76 3,627,510 12/1971 Vogt et a1 75-76 411,205 9/ 1889 Slocum 75-59 X 482,001 9/1892 Brazelle 75-59 1,783,726 12/1930 Lappe 75-59 X 3,046,107 7/ 1962 Nelson 75-59 3,169,058 2/1965 Nelson 75-59 X 3,252,790 5/1966 Krivsky 75-60 3,427,151 2/ 1969 Koudelka 75-59 OTHER REFERENCES G. R. Fitterer, C. D. Cassley, V. Vierbicky: The Rapid Determination of Oxygen in Commercial Steel with the Solid Electrolyte Probe, Journal of Metals, June 1968, pp. 74-76.
L. DIEWAYNE RUTLEDGE, Primary Examiner J. E. LEGRU, Assistant Examiner US. Cl. X.R. 75-59
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Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3816104A (en) * 1970-09-25 1974-06-11 Allegheny Ludlum Ind Inc Deoxidizing nickel base and cobalt base alloys
US3844768A (en) * 1971-05-28 1974-10-29 Creusot Loire Process for refining alloy steels containing chromium and including stainless steels
US3891429A (en) * 1973-06-07 1975-06-24 Koppers Co Inc Method for selective decarburization of alloy steels
US3898078A (en) * 1973-03-29 1975-08-05 Youngstown Sheet And Tube Co Method and apparatus for injecting refining oxygen in steelmaking processes
US3907548A (en) * 1973-07-04 1975-09-23 Krupp Ag Huettenwerke Process for the production of steels having high chromium content and lowest possible carbon content
US3930843A (en) * 1974-08-30 1976-01-06 United States Steel Corporation Method for increasing metallic yield in bottom blown processes
US4047937A (en) * 1972-12-04 1977-09-13 United States Steel Corporation Method for controlling the operation of a steel refining converter
US4081270A (en) * 1977-04-11 1978-03-28 Union Carbide Corporation Renitrogenation of basic-oxygen steels during decarburization
US4746361A (en) * 1987-04-03 1988-05-24 Inland Steel Company Controlling dissolved oxygen content in molten steel
EP0340893A1 (en) * 1988-05-02 1989-11-08 William M. Tekatch Removal of nitrogen from iron

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4515630A (en) * 1983-08-15 1985-05-07 Olin Corporation Process of continuously treating an alloy melt
FR3125542A1 (en) 2021-07-23 2023-01-27 Pda Ecolab Hybridization of natural fiber reinforcement for composite materials and fabrics made therefrom

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU28302A1 (en) * 1945-02-14
US3218156A (en) * 1963-10-16 1965-11-16 Howe Sound Co Process for vacuum deoxidation of alloys
US3725041A (en) * 1970-09-25 1973-04-03 Allegheny Ludlum Ind Inc Deoxidizing metal

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3816104A (en) * 1970-09-25 1974-06-11 Allegheny Ludlum Ind Inc Deoxidizing nickel base and cobalt base alloys
US3844768A (en) * 1971-05-28 1974-10-29 Creusot Loire Process for refining alloy steels containing chromium and including stainless steels
US4047937A (en) * 1972-12-04 1977-09-13 United States Steel Corporation Method for controlling the operation of a steel refining converter
US3898078A (en) * 1973-03-29 1975-08-05 Youngstown Sheet And Tube Co Method and apparatus for injecting refining oxygen in steelmaking processes
US3891429A (en) * 1973-06-07 1975-06-24 Koppers Co Inc Method for selective decarburization of alloy steels
US3907548A (en) * 1973-07-04 1975-09-23 Krupp Ag Huettenwerke Process for the production of steels having high chromium content and lowest possible carbon content
US3930843A (en) * 1974-08-30 1976-01-06 United States Steel Corporation Method for increasing metallic yield in bottom blown processes
US4081270A (en) * 1977-04-11 1978-03-28 Union Carbide Corporation Renitrogenation of basic-oxygen steels during decarburization
US4746361A (en) * 1987-04-03 1988-05-24 Inland Steel Company Controlling dissolved oxygen content in molten steel
EP0340893A1 (en) * 1988-05-02 1989-11-08 William M. Tekatch Removal of nitrogen from iron

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US3816104A (en) 1974-06-11
CA947976A (en) 1974-05-28
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