US3826647A - Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace - Google Patents

Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace Download PDF

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Publication number
US3826647A
US3826647A US00306138A US30613872A US3826647A US 3826647 A US3826647 A US 3826647A US 00306138 A US00306138 A US 00306138A US 30613872 A US30613872 A US 30613872A US 3826647 A US3826647 A US 3826647A
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US
United States
Prior art keywords
lime
oxygen
blow
rate
carbon
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.)
Expired - Lifetime
Application number
US00306138A
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English (en)
Inventor
D Dukelow
P Hunter
R King
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United States Steel Corp
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Steel Corp
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
Priority to BE792124D priority Critical patent/BE792124A/xx
Application filed by Steel Corp filed Critical Steel Corp
Priority to US00306138A priority patent/US3826647A/en
Priority to IT32465/72A priority patent/IT982369B/it
Priority to FR7243249A priority patent/FR2162461B1/fr
Priority to AR245481A priority patent/AR198963A1/es
Priority to GB5611072A priority patent/GB1415535A/en
Priority to ES409323A priority patent/ES409323A1/es
Priority to NL7216486A priority patent/NL7216486A/xx
Priority to DE2259533A priority patent/DE2259533A1/de
Priority to CA158,066A priority patent/CA974774A/en
Priority to LU66599A priority patent/LU66599A1/xx
Priority to TR17930A priority patent/TR17930A/xx
Priority to SE7215839A priority patent/SE407694B/xx
Priority to PL15930972A priority patent/PL79118B1/pl
Priority to DD167322A priority patent/DD102164A5/xx
Priority to JP12236072A priority patent/JPS5545607B2/ja
Application granted granted Critical
Publication of US3826647A publication Critical patent/US3826647A/en
Assigned to USX CORPORATION, A CORP. OF DE reassignment USX CORPORATION, A CORP. OF DE MERGER (SEE DOCUMENT FOR DETAILS). Assignors: UNITED STATES STEEL CORPORATION (MERGED INTO)
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • C21C5/34—Blowing through the bath
    • 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

Definitions

  • a new basic-steelmaking process is beginning to receive considerable attention in the United States.
  • this new process utilizes a combination of an oxygen blow and a lime-containing basic slag to remove impurities from molten pig iron.
  • this new process blow oxygen through tuyeres located below the surface of the molten metal.
  • the tuyeres are located in the bottom of the vessel, in a manner similar to that of the Bessemer process.
  • a similar tuyere system is employed in the side of the vessel or hearth. Combinations of these embodiments may also be employed.
  • these new tuyeres are comprised of a generally concentric tube system in which the central tuyere is employed for the oxygen stream.
  • Each oxygen tuyere is surrounded by a larger tuyere for the simultaneous injection of a protective coolant fluid which serves to jacket the oxygen stream.
  • This jacket 'fluid may be natural gas, other hydrocarbon containing liquids or gases or in some instances relatively non-reactive type gases such as argon, ammonia or carbon monoxide.
  • the jacket fluid acts as a coolant, reducing the rate of reaction between the molten metal and oxygen adjacent the tuyere and thereby preventing the rapid erosion of both the tuyere itself and the adjacent refractory.
  • the term bottom blown process will therefore include all processes in which at least one tuyere system is located between the surface of the molten steel.
  • lime powder is entrained in the oxygen stream and blown into the bath to flux the oxidized impurities.
  • it is conventional (in European practice) to provide an extensive oxygen blow and thereby decrease the carbon to a rather low residual level. Thus, if it is desirable to produce a.
  • the bottom blow processes achieve substantially enhanced mixing during the blow, hence equilibrium conditions are more closely approached. While this is beneficial in improving the yield (substantially less iron oxide in the slag), the amount of phosphorus in the bath at the end of the blow is considerably greater. Thus, in the bottom blown process, phosphorus has only been substantially removed (i.e. greater than about reduction) after the carbon has been reduced to rather low levels.
  • the above-mentioned benefits of catch carbon" practice have not been available to the art in many instances. For example, in utilizing pig irons with phosphorus contents in excess of about 0.14%, the production of a steel with phosphorus below about 0.025% has not been readily achievable. Similarly, even with pig irons with low initial phosphorus contents (e.g. 0.04 to 0.06% it is often desirable to produce a steel with only about 0.005 to 0.01% phosphorus.
  • FIGS. 1 through 9 are graphical representations of the lime load patterns employed in the examples of Table I.
  • the end-point temperature of the metal bath be kept within rather specific limits.
  • the desired end-point temperature is primarily dependent of the final, desired carbon level of the steel. Methods for controlling the end-point temperature, such as by proper control of charge (e.g. hot metal to scrap ratio) are well known to the art. Therefore consistent with good pouring practice, the end-point temperature (T should not exceed that given by the following equation:
  • T F. 2940100(C)
  • Example 9 is illustrative of a further preferred embodiment of the invention, in which finely divided iron oxide was simultaneously injected together with the lime during final portion of the blow, preferably during the final 25% of the period.
  • the patterns employed in Examples 5, 7 and 8 are illustrative of particularly preferred embodiments of the instant invention, wherein the lime load rate for about the last 40% of the blowing period is equal to or greater than about 1.5 times that of L A number of other modifications of the prescribed practice may also be employed.
  • the sulfur content of the pig iron is high, i.e., greater than 0.05%, it may be desirable to employ a comparative high lime load rate (i.e., greater than L during about the first 25% of the blow.
  • Desulfurization is favored by reducing condi- TABLE I.HEAT DATA Steel Pig iron (liquid) Blowing Lime percent time, loading, Composition, percent min., Oxygen, lbs./ Temp,
  • Example number Charge materials, lbs. I S Si percent s.c.t'.m. s.e.f. Oz 0 P S Si F 1 58,300 liq. pig iron 0. 23 1 O. 048 0.79 8 (60) 3, 000 0. 11
  • tions which are present when the silicon content of the metal bath is high, i.e., during about the first 25% of the period. If a high lime load is, in fact, employed during the first 25% of the blow, say 0.15 lbs./ft. it is nevertheless essential that the average for the first 50% of the blow be within the prescribed practice. Thus, a lime load of, for example, 0.04 lbs./ft. could be employed for the second 25% of the blowing period.
  • the lime for any period was injected at a constant rate, i.e. the slope of the patterns shown in the figures is zero.
  • the invention is not limited to the use of such zero slope load patterns.
  • the lime may also be added at an increasing rate (positive slope) or at a decreasing rate (negative slope). It is only essential for purposes of this invention that the area under the curve for the whole blow, provide an average lime load rate L,
  • the improvement which comprises adding said lime at a rate to achieve an overall lime load rate L of 0.09 to 0.16 pounds of lime per ft. of oxygen, wherein the average lime load rate for the first half of the blowing period L is at least 10 percent less than L and the average lime load rate for the second half of the blowing period L is at least 10 percent greater than L and controlling the end-point temperature of said refined molten steel so that it does not exceed that given by the equation:

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
US00306138A 1971-12-06 1972-11-13 Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace Expired - Lifetime US3826647A (en)

Priority Applications (16)

Application Number Priority Date Filing Date Title
BE792124D BE792124A (fr) 1971-12-06 Procede de fabrication d'acier
US00306138A US3826647A (en) 1971-12-06 1972-11-13 Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace
IT32465/72A IT982369B (it) 1971-12-06 1972-12-04 Metodo per ottenere bassi contenu ti di fosforo in acciai a medio e alto tenore di carbonio in un forno per la fabbricazione di acciaio con ossigeno insuffiato dal basso
SE7215839A SE407694B (sv) 1971-12-06 1972-12-05 Forfarande for framstellning av stal med lag fosforhalt
GB5611072A GB1415535A (en) 1971-12-06 1972-12-05 Method of obtaining low-phosphorous contents in mediu-and high-carbon steels in a bottom-blown oxygen steel-making furnace
ES409323A ES409323A1 (es) 1971-12-06 1972-12-05 Procedimiento de inyeccion por el fondo para el refino de hierro fundido.
NL7216486A NL7216486A (enrdf_load_html_response) 1971-12-06 1972-12-05
DE2259533A DE2259533A1 (de) 1971-12-06 1972-12-05 Bodenblasendes frischverfahren
FR7243249A FR2162461B1 (enrdf_load_html_response) 1971-12-06 1972-12-05
LU66599A LU66599A1 (enrdf_load_html_response) 1971-12-06 1972-12-05
TR17930A TR17930A (tr) 1971-12-06 1972-12-05 Dipten ueflenen bir oksijenle celik yapi mi firininda orta-ve yueksek-karbon celiklerinde alcak-fosfor muhtevasi elde etme usulue
AR245481A AR198963A1 (es) 1971-12-06 1972-12-05 Metodo para obtener acero con bajo contenido de fosforo
PL15930972A PL79118B1 (enrdf_load_html_response) 1972-11-13 1972-12-05
CA158,066A CA974774A (en) 1971-12-06 1972-12-05 Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace
DD167322A DD102164A5 (enrdf_load_html_response) 1971-12-06 1972-12-06
JP12236072A JPS5545607B2 (enrdf_load_html_response) 1971-12-06 1972-12-06

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US20535371A 1971-12-06 1971-12-06
US00306138A US3826647A (en) 1971-12-06 1972-11-13 Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace

Publications (1)

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US3826647A true US3826647A (en) 1974-07-30

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US00306138A Expired - Lifetime US3826647A (en) 1971-12-06 1972-11-13 Method of obtaining low-phosphorus contents in medium-and high-carbon steels in a bottom-blown oxygen steelmaking furnace

Country Status (15)

Country Link
US (1) US3826647A (enrdf_load_html_response)
JP (1) JPS5545607B2 (enrdf_load_html_response)
AR (1) AR198963A1 (enrdf_load_html_response)
BE (1) BE792124A (enrdf_load_html_response)
CA (1) CA974774A (enrdf_load_html_response)
DD (1) DD102164A5 (enrdf_load_html_response)
DE (1) DE2259533A1 (enrdf_load_html_response)
ES (1) ES409323A1 (enrdf_load_html_response)
FR (1) FR2162461B1 (enrdf_load_html_response)
GB (1) GB1415535A (enrdf_load_html_response)
IT (1) IT982369B (enrdf_load_html_response)
LU (1) LU66599A1 (enrdf_load_html_response)
NL (1) NL7216486A (enrdf_load_html_response)
SE (1) SE407694B (enrdf_load_html_response)
TR (1) TR17930A (enrdf_load_html_response)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4987086A (en) * 1987-11-30 1991-01-22 Becton, Dickinson And Company Method for analysis of subpopulations of cells

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5743919A (en) * 1980-08-30 1982-03-12 Kawasaki Steel Corp Method for blow refining in top and/or bottom-blown converter
JPS57140810A (en) * 1981-02-23 1982-08-31 Nippon Steel Corp Refining method for steel
JPS6284354U (enrdf_load_html_response) * 1985-11-14 1987-05-29
JPS62111761U (enrdf_load_html_response) * 1986-01-07 1987-07-16

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4987086A (en) * 1987-11-30 1991-01-22 Becton, Dickinson And Company Method for analysis of subpopulations of cells

Also Published As

Publication number Publication date
JPS4876715A (enrdf_load_html_response) 1973-10-16
AR198963A1 (es) 1974-07-31
FR2162461A1 (enrdf_load_html_response) 1973-07-20
GB1415535A (en) 1975-11-26
BE792124A (fr) 1973-03-16
JPS5545607B2 (enrdf_load_html_response) 1980-11-19
TR17930A (tr) 1976-11-01
DE2259533A1 (de) 1973-06-14
ES409323A1 (es) 1976-03-16
CA974774A (en) 1975-09-23
IT982369B (it) 1974-10-21
LU66599A1 (enrdf_load_html_response) 1973-02-08
SE407694B (sv) 1979-04-09
NL7216486A (enrdf_load_html_response) 1973-06-08
DD102164A5 (enrdf_load_html_response) 1973-12-05
FR2162461B1 (enrdf_load_html_response) 1977-01-14

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AS Assignment

Owner name: USX CORPORATION, A CORP. OF DE, STATELESS

Free format text: MERGER;ASSIGNOR:UNITED STATES STEEL CORPORATION (MERGED INTO);REEL/FRAME:005060/0960

Effective date: 19880112