US2662819A - Production of transformer and dynamo steels - Google Patents

Production of transformer and dynamo steels Download PDF

Info

Publication number
US2662819A
US2662819A US233264A US23326451A US2662819A US 2662819 A US2662819 A US 2662819A US 233264 A US233264 A US 233264A US 23326451 A US23326451 A US 23326451A US 2662819 A US2662819 A US 2662819A
Authority
US
United States
Prior art keywords
per cent
steel
ladle
steels
temperature
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
US233264A
Inventor
Hofges Heinz
Goebel Ernst
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.)
Individual
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
Application granted granted Critical
Publication of US2662819A publication Critical patent/US2662819A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon

Definitions

  • a pig iron having a comparatively high content of phosphorous and manganese is charged into a Bessemer converter, blasted until the carbon is reduced to about 0.02 per cent, the manganese to less than 0.30 per cent, the sulfur to less than 0.05 per cent and the phosphorous to about 0.08 to 0.12 per cent.
  • the temperature during this treatment is maintained at about 1650 C.
  • the thus treated steel is, upon separation from the slag, transferred into a first ladle; here it is treated with a basic oxidizing slag, for instance slags containing, in addition to silica, alkali, earth alkali oxide, iron oxide, earth alkali carbonates and fluorspar.
  • a basic oxidizing slag for instance slags containing, in addition to silica, alkali, earth alkali oxide, iron oxide, earth alkali carbonates and fluorspar.
  • a suitable composition of these slags is twothirds of sodium carbonate and one-third of iron oxide or equal parts of sodium carbonate, calcium carbonate and iron oxide.
  • the slags used during the first ladle treatment may be applied in a presintered or premelted condition; they act to reduce the phosphorous of the melt substantially to the amount, which is desired in the final steel.
  • the percentages of 0, Mn, P and S of the steel after the first ladle treatment may preferably be 0.02 per cent C, less than 0.20 per cent Mn, less than 0.04 per cent P and less than 0.03 per cent S.
  • the treating tempera ture in the first ladle is 1620-1650" C.
  • the steel which has been blasted in the Bessemer converter and has been oxidized and dephosphorized in a first ladle is transferred into a second ladle; here it is treated with ferro-silicon or calciumsilicon and aluminum and hereby enriched with silicon anddeoxidized; the temperature is raised by the reaction to about 1670-4680 C. After standing for about thirtyminuteathe steel is poured at atemperature of about l6 00 C.
  • This second ladle treatment is performed at a comparatively high temperature produced by the action of the silicon and aluminum which renders it possible, to pour the final steel in spite of longerperiods of standing at a temperature of about 1600 0,
  • the instant method for the production of dynamo and transformer steels having a high content of up to about 4 per centSi is based on the successivetreatment in a Bessemer converter, in a first andin a, sec
  • the steel is subjected in the Bessemer converter to an initial oxidation; the phosphorous content of the steel is reduced to about 0.08 per cent to 0.12 per cent.
  • the main oxidation and particularly the main removal of the phosphorous practically up to the final limits is hereupon carried-out in the first ladle. In this manner, the phosphorous removal and the refining of the steel by oxidation is separated from its silicon enrichment and its deoxidation which is therefore carried-out in the second ladle.
  • the steel can be kept sufficiently fluid in the second ladle in spite of the admixture of the silicon and the aluminum; this preservation of the high fluidity of the bath is important, as it enables in the second ladle an easy and effective introduction of the silicon into and removal of the oxygen from, the molten steel; at the same time, the calcium of the calcium silicide evaporates and thoroughly penetrates the bath; it liquefies the alumina, the silicates and the sulfur, which latter in the strongly bubbling melt is converted into calcium sulfide.
  • the steel which becomes heated in the second ladle to a temperature of about 1670-1680 C, is
  • Example 17,000 kilograms of pig iron containing 3.3 per cent C, 0.7 per cent Mn, 1.5 per cent Si, 0.11 per cent P and 0.03 per cent S are charged into a Bessemer converter and blasted in the usual manner at a temperature of about 1670 C.
  • the steel is separated from the slag and poured into a first ladle; 400 kilograms of an oxidizing slag containing 60 per cent CaO, 29 per cent F6203, 3 per cent S102 and 2 per cent A1203 and heated to about 1700 C. are added. After a treatment of about two minutes, a steel results of the following composition:
  • the steel Upon removal of the thinly fluid slag, the steel is transferred into a second ladle.
  • the following alloying and slag forming agents are added:
  • the steel temperature then rises up to about 1680 C.
  • composition of the steel is now:
  • composition of the slag is:
  • the steel is left standing for about thirty minutes, whereby the temperature drops to about 1600 C.
  • the steel is cast at this temperature.
  • a method for the production of high silicon transformer and dynamo steels comprising charging a pig iron containing up to about 1.0 per cent Mn and up to about 0.12 per cent P into a Bessemer converter, blasting the metal at a temperature of about 1650-1680 C. to produce steel having about 0.02 per cent C, less than 0.3 per cent Mn, up to about 0.12 per cent P and less than 0.05 per cent S.
  • tapping the steel into a first ladle refining the same in said ladle by the admixture of a basic calcium and iron silicate slag to about 0.01 per cent C, to less than 0.20 per cent Mn, less than 0.04 per cent P, and less than 0.03 per cent S, transferring the steel into a second ladle, adding to the steel in said second ladle a mixture of Al, CaFz and of a substance selected from the group consisting of Casi and FeSi, treating the steel with the said mixture until the desired silicon content and a temperature is reached of about 1680 C., keeping the steel at rest for about thirty minutes and pouring the same at a temperature of about 1600 C.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Description

Patented Dec. 15, 1953 PRODUCTION OF TRANSFORMER AND DYNAMO STEELS I Heinz Hiifges and Ernst Goebel, Hamborn, Germany No Drawing, Application June23-, 1951, l 7 Serial No. 233,264
Claims priority, application Germany February 28, 1949 1 Claim. (01. 75-129) This invention relates to theproduction of transformer and dynamo, steels; it is a continuation-in-part of our copending U. S. patent application Ser. No. 108,664, filed August 4, 1949, now abandoned.
To date, dynamo and transformer steels have been exclusively manufactured in open hearth and in electric furnaces.
In order to eliminate the high operational costs of these furnaces, attempts have been made to produce these steels in a converter. For this purpose, a high phosphorus steel was blasted in a basic converter at a low temperature and this steel was hereafter subjected to a combined oxidizing and silicon enriching treatment in a ladle. The reduction of the phosphorous was eifected in the basic converter at a low temperature; the refining of the steel and the admixture of the silicon was carried out in the ladle.
It is an object of the invention to eliminate the disadvantages resulting from the maintenance of a low temperature in the basic converter.
It is a nother important object, of the invention to avoid the grave difiiculties arising from the simultaneous oxidation, dephosphorization and silicon introduction in the ladle.
With the above stated objects in view, a pig iron having a comparatively high content of phosphorous and manganese is charged into a Bessemer converter, blasted until the carbon is reduced to about 0.02 per cent, the manganese to less than 0.30 per cent, the sulfur to less than 0.05 per cent and the phosphorous to about 0.08 to 0.12 per cent.
The temperature during this treatment is maintained at about 1650 C.
The thus treated steel is, upon separation from the slag, transferred into a first ladle; here it is treated with a basic oxidizing slag, for instance slags containing, in addition to silica, alkali, earth alkali oxide, iron oxide, earth alkali carbonates and fluorspar.
A suitable composition of these slags is twothirds of sodium carbonate and one-third of iron oxide or equal parts of sodium carbonate, calcium carbonate and iron oxide.
The slags used during the first ladle treatment may be applied in a presintered or premelted condition; they act to reduce the phosphorous of the melt substantially to the amount, which is desired in the final steel. The percentages of 0, Mn, P and S of the steel after the first ladle treatment may preferably be 0.02 per cent C, less than 0.20 per cent Mn, less than 0.04 per cent P and less than 0.03 per cent S. The treating tempera ture in the first ladle is 1620-1650" C.
The final treatment of the steel being a separate process step is of particular importance.
'In conformity therewith the steel which has been blasted in the Bessemer converter and has been oxidized and dephosphorized in a first ladle is transferred into a second ladle; here it is treated with ferro-silicon or calciumsilicon and aluminum and hereby enriched with silicon anddeoxidized; the temperature is raised by the reaction to about 1670-4680 C. After standing for about thirtyminuteathe steel is poured at atemperature of about l6 00 C.
This second ladle treatment is performed at a comparatively high temperature produced by the action of the silicon and aluminum which renders it possible, to pour the final steel in spite of longerperiods of standing at a temperature of about 1600 0,
As apparent'from the above, the instant method for the production of dynamo and transformer steels having a high content of up to about 4 per centSi is based on the successivetreatment in a Bessemer converter, in a first andin a, sec
ond ladle, each of these devices serving its particular purpose and thereby eliminating the above mentioned disadvantages of the prior art.
The steel is subjected in the Bessemer converter to an initial oxidation; the phosphorous content of the steel is reduced to about 0.08 per cent to 0.12 per cent. The main oxidation and particularly the main removal of the phosphorous practically up to the final limits is hereupon carried-out in the first ladle. In this manner, the phosphorous removal and the refining of the steel by oxidation is separated from its silicon enrichment and its deoxidation which is therefore carried-out in the second ladle.
By this subdivision of the refining treatment and the silicon introduction in two separate steps carried-out in two ladles the steel can be kept sufficiently fluid in the second ladle in spite of the admixture of the silicon and the aluminum; this preservation of the high fluidity of the bath is important, as it enables in the second ladle an easy and effective introduction of the silicon into and removal of the oxygen from, the molten steel; at the same time, the calcium of the calcium silicide evaporates and thoroughly penetrates the bath; it liquefies the alumina, the silicates and the sulfur, which latter in the strongly bubbling melt is converted into calcium sulfide.
The steel which becomes heated in the second ladle to a temperature of about 1670-1680 C, is
left standing for about thirty minutes and is then poured at a. temperature of about 1600 C.
It is apparent from the above that the subdivision of the final treatment into two ladle steps is of decisive importance for a successful execution of the invention.
The latter is more in detail described in the following example.
Example 17,000 kilograms of pig iron containing 3.3 per cent C, 0.7 per cent Mn, 1.5 per cent Si, 0.11 per cent P and 0.03 per cent S are charged into a Bessemer converter and blasted in the usual manner at a temperature of about 1670 C. A steel results having about 0.02 per cent C, about 0.15 per cent Mn, about 0.12 per cent P and about 0.03 per cent S.
The steel is separated from the slag and poured into a first ladle; 400 kilograms of an oxidizing slag containing 60 per cent CaO, 29 per cent F6203, 3 per cent S102 and 2 per cent A1203 and heated to about 1700 C. are added. After a treatment of about two minutes, a steel results of the following composition:
- 0.01 per cent carbon, 0.08 per cent Mn, 0.03 per cent P, 0.02 per cent S and having a temperature of about 1650 C.
Upon removal of the thinly fluid slag, the steel is transferred into a second ladle. The following alloying and slag forming agents are added:
200 kilograms CaSi, 590 kilograms FeSi, 45 kilograms, Al, kilograms CaFz.
The steel temperature then rises up to about 1680 C.
The composition of the steel is now:
0.02 per cent C, 0.08 per cent Mn, 0.02 per cent P, 0.004 per cent S, 4.3 per cent Si, 0.28 per cent Al, rest iron.
The composition of the slag is:
0.2 per cent Fe, 0.15 per cent Mn, 0.06 per cent P, 24 per cent A1203, 11 per cent $102, 55 per cent CaO, 4 per cent F, 2 per cent MgO, 0.5 per cent S.
The steel is left standing for about thirty minutes, whereby the temperature drops to about 1600 C. The steel is cast at this temperature.
Since certain changes in carrying out the above process could be made without departing from the scope thereof, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.
Having thus described the invention, what we claim as new and desire to be secured by Letters Patent, is as follows:
A method for the production of high silicon transformer and dynamo steels, comprising charging a pig iron containing up to about 1.0 per cent Mn and up to about 0.12 per cent P into a Bessemer converter, blasting the metal at a temperature of about 1650-1680 C. to produce steel having about 0.02 per cent C, less than 0.3 per cent Mn, up to about 0.12 per cent P and less than 0.05 per cent S. tapping the steel into a first ladle, refining the same in said ladle by the admixture of a basic calcium and iron silicate slag to about 0.01 per cent C, to less than 0.20 per cent Mn, less than 0.04 per cent P, and less than 0.03 per cent S, transferring the steel into a second ladle, adding to the steel in said second ladle a mixture of Al, CaFz and of a substance selected from the group consisting of Casi and FeSi, treating the steel with the said mixture until the desired silicon content and a temperature is reached of about 1680 C., keeping the steel at rest for about thirty minutes and pouring the same at a temperature of about 1600 C.
HEINZ HoFGEs. ERNST GOEBEL.
References Cited in the file of this patent UNITED STATES PATENTS Name Date Perrin Oct. 1, 1935 OTHER REFERENCES Number
US233264A 1949-02-28 1951-06-23 Production of transformer and dynamo steels Expired - Lifetime US2662819A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2662819X 1949-02-28

Publications (1)

Publication Number Publication Date
US2662819A true US2662819A (en) 1953-12-15

Family

ID=7996512

Family Applications (1)

Application Number Title Priority Date Filing Date
US233264A Expired - Lifetime US2662819A (en) 1949-02-28 1951-06-23 Production of transformer and dynamo steels

Country Status (1)

Country Link
US (1) US2662819A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3099552A (en) * 1958-10-21 1963-07-30 Gen Electric Method of making low sulfur steel
US3236637A (en) * 1961-06-26 1966-02-22 Voest Ag Process of continuously converting molten crude iron into steel
US3318691A (en) * 1965-07-06 1967-05-09 Jellinghaus Rudolf Process for producing castings from an iron alloy containing silicon
US4761178A (en) * 1987-08-24 1988-08-02 Bethlehem Steel Corporation Process for heating molten steel contained in a ladle

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2015692A (en) * 1931-08-31 1935-10-01 Electrochimie Electrometallurg Process of dephosphorizing steel

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2015692A (en) * 1931-08-31 1935-10-01 Electrochimie Electrometallurg Process of dephosphorizing steel

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3099552A (en) * 1958-10-21 1963-07-30 Gen Electric Method of making low sulfur steel
US3236637A (en) * 1961-06-26 1966-02-22 Voest Ag Process of continuously converting molten crude iron into steel
US3318691A (en) * 1965-07-06 1967-05-09 Jellinghaus Rudolf Process for producing castings from an iron alloy containing silicon
US4761178A (en) * 1987-08-24 1988-08-02 Bethlehem Steel Corporation Process for heating molten steel contained in a ladle
WO1989001984A1 (en) * 1987-08-24 1989-03-09 Bethlehem Steel Corporation Process for heating molten steel contained in a ladle

Similar Documents

Publication Publication Date Title
US3809547A (en) Electric furnace steelmaking process using oxide of boron additive
US2662819A (en) Production of transformer and dynamo steels
CA1079072A (en) Arc steelmaking
US2781256A (en) Process for the rapid removal of sulphur and silicon from pig iron
GB1025230A (en) Improvements in the production of alloy steel
JPH0141681B2 (en)
JPH08157921A (en) Dephosphorization of molten iron
US2079848A (en) Making steel
CN110964878A (en) Dephosphorizing agent for efficiently dephosphorizing for converter and preparation method and application thereof
US2670283A (en) Refining steel
US2207109A (en) Manufacture of steel
JP2001049320A (en) Production of iron and steel using high phosphorus ore as raw material
US2767078A (en) Process for desiliconizing and desulphurizing pig iron
US1459712A (en) Process for the production of basic steel
US2111893A (en) Method of making steel
US2350725A (en) Process for recovering metals from steel slags
US2855289A (en) Fluidizing slags of open hearth and electric furnace steel making processes using eutectic mixture
US1979753A (en) Open-hearth slag utilization
JP3194212B2 (en) Converter steelmaking method
JPS6154083B2 (en)
US2188416A (en) Process for rapidly obtaining steels of high purity
GB492740A (en) Improvements in and relating to the dephosphorising and/or desulphurising of steel
JPH09176717A (en) Method for steelmaking molten iron of blast furnace
RU1801143C (en) Method of ferrovanadium smelting
US788650A (en) Continuous process of manufacturing steel.