US2496074A - Process for deoxidizing iron and steel - Google Patents
Process for deoxidizing iron and steel Download PDFInfo
- Publication number
- US2496074A US2496074A US679865A US67986546A US2496074A US 2496074 A US2496074 A US 2496074A US 679865 A US679865 A US 679865A US 67986546 A US67986546 A US 67986546A US 2496074 A US2496074 A US 2496074A
- Authority
- US
- United States
- Prior art keywords
- slag
- ferro
- silicon
- metal
- lump
- 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
Links
- 238000000034 method Methods 0.000 title claims description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims description 18
- 229910052742 iron Inorganic materials 0.000 title claims description 9
- 229910000831 Steel Inorganic materials 0.000 title description 13
- 239000010959 steel Substances 0.000 title description 13
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 41
- 239000002893 slag Substances 0.000 claims description 38
- 230000000903 blocking effect Effects 0.000 claims description 13
- 239000000080 wetting agent Substances 0.000 claims description 12
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 10
- 229910052799 carbon Inorganic materials 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 239000002184 metal Substances 0.000 description 24
- 229910052751 metal Inorganic materials 0.000 description 24
- 238000007792 addition Methods 0.000 description 12
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 11
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 235000013980 iron oxide Nutrition 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 150000004760 silicates Chemical class 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 239000004317 sodium nitrate Substances 0.000 description 2
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 description 1
- 229910001021 Ferroalloy Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001642 boronic acid derivatives Chemical class 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical class [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- VBMVTYDPPZVILR-UHFFFAOYSA-N iron(2+);oxygen(2-) Chemical class [O-2].[Fe+2] VBMVTYDPPZVILR-UHFFFAOYSA-N 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 150000002978 peroxides Chemical class 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
Classifications
-
- 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
-
- 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
- C21C5/04—Manufacture of hearth-furnace steel, e.g. Siemens-Martin steel
Definitions
- the invention relates to improvements in the manufacture of iron and steel and particularly to that part of the process known as blocking.
- the amount of silicon added in this manner usually ranges from 06% to depending upon the degree of oxidation of the metal and the length of time it is desired to block the same.
- silica is formed as a result of the oxidation of the silicon, and this silica remains trapped, or in solution, in the molten metal resulting in objectionable inclusions in the finished steel.
- Another method employed in blocking steel or iron in the furnace consists in adding powdered 50% ferro-silicon to the slag when the bath has reached the desired carbon content.
- This method of deoxidation lowers the FeO content of the slag causing the Foo to flow from the metal to the slag which lowers the FeO in the bath below the point where it will react with the carbon in the metal.
- Another object is to provide a more economical method of effectively blocking the heat.
- a further object is to provide a method of blocking the heat which produces a cleaner steel.
- Still another object is to provide a method of blocking iron or steel heats by the addition of lumps of dense 30% to ferro-silicon.
- a still further object of the invention is to provide such a method which includes the addition of lumps of 30% to 60% ferro-silicon which have been treated with a wetting agent.
- wetting agents are suitable for this purpose, such as the group or products known as oxidants which are compounds having available free oxygen such as sodium nitrate, sodium chlorate, peroxides, permanganates, etc.
- oxidants which are compounds having available free oxygen such as sodium nitrate, sodium chlorate, peroxides, permanganates, etc.
- Another wetting agent suitable for the purpose is a group of products containing halogens such as sodium chloride, calcium fluoride, etc.
- Still another group of suitable wetting agents are derived from the group of products consisting of reaction products of an acid with a metal, such as sulphates, chromates, borates, etc.
- the lump 30% to 60% ferro-silicon may be either immersed in, or sprayed with, a solution of the wetting agent so as to produce a film on the surface of the ferrosilicon.
- This film allows the ferro-silicon lumps to become wet by the slag immediately on addition to the furnace, and to sink through the slag to the inter-face between slag and metal. Due to its specific gravity, and low melting point, the lump 30% to 60% ferro-silicon goes in the solution immediately at the inter-face, thus effecting deoxidation at this point.
- silicates formed by reducing the iron oxides are formed close to the inter-face and are therefore absorbed by the slag producing a metal free from objectionable silicates.
- the wetting agent may be eliminated, and the invention can be successfully carried out without first coating the ferro-silicon lumps with a wetting agent, I have found that the use of a wetting agent has certain advantages and that when it is eliminated there is more deoxidation of the slag than when it is used and therefore more possibility of a phosphorous reversion.
- I claim 1 In the manufacture of iron and steel, the method of blocking the heat when it has reached the desired carbon content, which consists in coating one inch and larger lump dense 50% ferro-silicon with the film of a wetting agent which will allow the lump ferro-silicon to become wet by molten slag, and adding the coated lump ferro-silicon to the furnace bath, whereby the lump ferro-silicon immediately becomes wet by the slag and sinks through the slag and immediately goes into solution at the inter-face between slag and metal, in an amount suflicient to effectively deoxidize the upper layer of the metal and the lower layer of the slag in the region of the interface.
- the method of blocking the heat when it has reached the desired carbon content which consists in coating one inch and larger lump dense 50% ferro-silicon with a film of sodium nitrate which will allow the lump ferro-silicon to become wet by molten slag, and adding the coated lump ferro-silicon to the furnace bath, whereby the lump ferro-silicon immediately becomes wet by the slag and sinks through the slag and immediately goes into solution at the inter-face between slag and metal, in an amount sufficient to effectively deoxidize the upper layer of the metal and the lower layer of the slag in the region of the inter-face.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Description
Patented Jan. 31, 1950 PROCESS FOR DEOXIDIZING IRON AND STEEL James C. Vignos, Canton, Ohio, assignor to Ohio Ferro Alloys Corporation, Canton,
poration of Ohio Ohio, a cor- No Drawing. Application June 27, 1946, Serial No. 679,865
2 Claims.
The invention relates to improvements in the manufacture of iron and steel and particularly to that part of the process known as blocking.
In the manufacture of killed steels, and where blocking of the heat in the furnace is required, it is customary to stop the action of the bath by the addition of to l&% ferro-silicon. This addition of the 10% to 14% ferro-silicon sinks through the slag and into the molten metal below and goes into solution thus efiecting deoxidation of the molten metal to a point where the reaction between the carbon content and the FeO content is stopped.
The amount of silicon added in this manner usually ranges from 06% to depending upon the degree of oxidation of the metal and the length of time it is desired to block the same.
During the period in which the heat is thus blocked considerable silica is formed as a result of the oxidation of the silicon, and this silica remains trapped, or in solution, in the molten metal resulting in objectionable inclusions in the finished steel.
Another method employed in blocking steel or iron in the furnace consists in adding powdered 50% ferro-silicon to the slag when the bath has reached the desired carbon content.
This method of deoxidation lowers the FeO content of the slag causing the Foo to flow from the metal to the slag which lowers the FeO in the bath below the point where it will react with the carbon in the metal.
There are certain disadvantages inherent in the use of both of the above methods of blocking the heat in an effort to prevent or retard further n carbon loss during the final step of the melt.
Where the 10% to 14% ferro-silicon addition is made to the bath the formation of undesirable inclusions cannot be prevented and in the method where the powdered 50% ferro-silicon is added to the slag for deoxidizing the same, it is difficult to prevent a phosphorous reversion into the steel from the slag.
I have discovered that a much improved practice results, if instead of deoxidizing the steel, by making additions of 10% to 14% ferro-silicon thereto, or deoxidizing the slag by the addition of powdered 50% ferro-silicon to the slag, as above described, lumps of to 60% ferro-silicon are added to the molten bath of slag and metal so as to go into solution immediately at the interface, thus effecting deoxidation at this point.
It is therefore an object of the invention to provide a much improved practice for deoxidizing or blocking iron or steel heats.
Another object is to provide a more economical method of effectively blocking the heat.
A further object is to provide a method of blocking the heat which produces a cleaner steel.
Still another object is to provide a method of blocking iron or steel heats by the addition of lumps of dense 30% to ferro-silicon.
A still further object of the invention is to provide such a method which includes the addition of lumps of 30% to 60% ferro-silicon which have been treated with a wetting agent.
The above objects together with others which will be apparent from the following description, or which may be later referred to, may be attained by carrying out the improved method in the manner hereinafter described in detail.
In carrying out the improved method, when the heat of metal has reached approximately the desired carbon content, there is added to the molten bath of slag and metal, lump 30% to 60% ferrosilicon which is preferably in the form of lumps of 50% ferro-silicon one inch in thickness and larger.
For this purpose I prefer to use dense ferrosilicon which is produced by casting in metal molds as described in U. S. Patent No. 2,197,660 of April 16, 1940,'to H. V. Glunz. The 50% ferrosilicon as produced in the past has been cast in sand beds producing a rather porous product.
The dense lump 30% to 60% ferro-silicon sinks through the slag to the inter-face between slag and metal, and I have further discovered that if sand cast lump 30% to 60% ferro-silicon is coated with a wetting agent it will also readily sink through the slag to the inter-face.
Further I have found that by coating lumps of dense 30% to 60% ferro-silicon with a wetting agent, they will sink more readily through the slag.
A great variety of wetting agents are suitable for this purpose, such as the group or products known as oxidants which are compounds having available free oxygen such as sodium nitrate, sodium chlorate, peroxides, permanganates, etc. Another wetting agent suitable for the purpose is a group of products containing halogens such as sodium chloride, calcium fluoride, etc.
Still another group of suitable wetting agents are derived from the group of products consisting of reaction products of an acid with a metal, such as sulphates, chromates, borates, etc.
The lump 30% to 60% ferro-silicon, either dense or sand cast, may be either immersed in, or sprayed with, a solution of the wetting agent so as to produce a film on the surface of the ferrosilicon.
This film allows the ferro-silicon lumps to become wet by the slag immediately on addition to the furnace, and to sink through the slag to the inter-face between slag and metal. Due to its specific gravity, and low melting point, the lump 30% to 60% ferro-silicon goes in the solution immediately at the inter-face, thus effecting deoxidation at this point.
Since the deoxidation thus takes place at the upper layer of the metal and the lower layer of the slag, transfer of FeO from the slag to the metal is retarded to a greater extent than if the deoxidation took place entirely in the slag or entirely in the metal.
The improved method of effecting deoxidation at the inter-face thus overcomes the objections inherent in the method of blocking the heat by the use of to 14% ferro-silicon, or powdered 50% ferro-silicon in the slag. I
The silicates formed by reducing the iron oxides are formed close to the inter-face and are therefore absorbed by the slag producing a metal free from objectionable silicates.
Further, since the deoxidation is mainly at the inter-face and not in the slag, there is no danger of phosphorous reversion from the slag to the metal.
Shortly after the lump to 60% ferrosilicon is added to the inter-face between the slag and metal of the bath the final additions of alloying elements or other deoxidizers may be made, and when these additions are melted the heat may be tapped.
Although in using the lump dense 30% to 60% ferro-silicon for arresting the action of the iron oxide on the carbon in the metal, the wetting agent may be eliminated, and the invention can be successfully carried out without first coating the ferro-silicon lumps with a wetting agent, I have found that the use of a wetting agent has certain advantages and that when it is eliminated there is more deoxidation of the slag than when it is used and therefore more possibility of a phosphorous reversion.
The proper amount of lump 30% to 60% ferro-silicon required for effectively blocking the heat can be readily and accurately determined by a few trial heats. For example, I have found that when a heat of 250,000 pounds had reached a carbon content of .20 and an addition of .12% of contained silicon in the form of lump 50% ferro-silicon was added to the furnace in 300 pounds lots through the second and fourth doors of the furnace, that in two or three minutes after the addition of the ferro-silicon the bath was effectively blocked and there were only a few occasional bubbles at the end of the bath. The
heat remained blocked for a total of twentyseven minutes before it was tapped.
From the above it will be evident that this method of deoxidation overcomes the disadvantages of prior practice and since the cheapest form of silicon available is that contained in 50% ferro-silicon, the process is more economical than prior practice.
I claim 1. In the manufacture of iron and steel, the method of blocking the heat when it has reached the desired carbon content, which consists in coating one inch and larger lump dense 50% ferro-silicon with the film of a wetting agent which will allow the lump ferro-silicon to become wet by molten slag, and adding the coated lump ferro-silicon to the furnace bath, whereby the lump ferro-silicon immediately becomes wet by the slag and sinks through the slag and immediately goes into solution at the inter-face between slag and metal, in an amount suflicient to effectively deoxidize the upper layer of the metal and the lower layer of the slag in the region of the interface.
2. In the manufacture of iron and steel, the method of blocking the heat when it has reached the desired carbon content, which consists in coating one inch and larger lump dense 50% ferro-silicon with a film of sodium nitrate which will allow the lump ferro-silicon to become wet by molten slag, and adding the coated lump ferro-silicon to the furnace bath, whereby the lump ferro-silicon immediately becomes wet by the slag and sinks through the slag and immediately goes into solution at the inter-face between slag and metal, in an amount sufficient to effectively deoxidize the upper layer of the metal and the lower layer of the slag in the region of the inter-face.
JAMES C. VIGNOS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,545,690 Petinot July 14, 1925 2,361,627 Herty Oct. 31, 1944 2,446,759 Griffiths Aug. 10, 1948 OTHER REFERENCES Basic Open Hearth Steel Making, (1944), pages -113, 230.
The Physical Chemistry of Steelmaking-Deoxidation with Silicon in the Basic Open Hearth Process (Cooperative Bulletin 38), page 7'7 (1930)
Claims (1)
1. IN THE MANUFACTURE OF IRON AND STEEL, THE METHOD OF BLOCKING THE HEAT WHEN IT HAS REACHED THE DESIRED CARBON CONTENT, WHICH CONSISTS IN COATING ONE INCH AND LARGER LUMP DENSE 50% FERRO-SILICON WITH THE FILM OF A WETTING AGENT WHICH WILL ALLOW THE LUMP FERRO-SILCON TO BECOME WET BY MOLTEN SLAG AND ADDING THE COATED LAMP FERRO-SILICON TO THE FURANCE BATH, WHEREBY THE LUMP FERRO-SILICON IMMEDIATELY BECOMES WET BY THE SLAG AND SINKS THROUGH THE SLAG AND IMMEDIATELY GOES INTO SOLUTION AT THE INTER-FACE BETWEEN SLAG AND METAL, IN AN AMOUNT SUFFICIENT TO EFFECTIVELY DEOXIDIZE THE UPPER LAYER OF THE METAL AND THE LOWER LAYER OF THE SLAG IN THE REGION OF THE INTERFACE.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US679865A US2496074A (en) | 1946-06-27 | 1946-06-27 | Process for deoxidizing iron and steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US679865A US2496074A (en) | 1946-06-27 | 1946-06-27 | Process for deoxidizing iron and steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2496074A true US2496074A (en) | 1950-01-31 |
Family
ID=24728686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US679865A Expired - Lifetime US2496074A (en) | 1946-06-27 | 1946-06-27 | Process for deoxidizing iron and steel |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2496074A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2639232A (en) * | 1951-10-19 | 1953-05-19 | Ohio Ferro Alloys Corp | Addition materials for iron and steel manufacture and method of use thereof |
| US2793949A (en) * | 1950-12-18 | 1957-05-28 | Imich Georges | Method of preparing composite products containing metallic and non-metallic materials |
| US3158465A (en) * | 1961-09-07 | 1964-11-24 | Kerchner Marshall & Company | Metallurgical material and process for treating iron therewith |
| US3256085A (en) * | 1961-09-29 | 1966-06-14 | United States Steel Corp | Method of coating aluminum and adding same to molten steel |
| US3314782A (en) * | 1963-12-12 | 1967-04-18 | Fur Tech Entwicklung Und Verwe | Refining agent for steel-works |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1545690A (en) * | 1924-02-11 | 1925-07-14 | Petinot Napoleon | Method of deoxidizing open-hearth-steel baths |
| US2361627A (en) * | 1942-04-29 | 1944-10-31 | Bethlehem Steel Corp | Slag deoxidation |
| US2446759A (en) * | 1945-10-22 | 1948-08-10 | Chromium Mining And Smelting C | Open-hearth process |
-
1946
- 1946-06-27 US US679865A patent/US2496074A/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1545690A (en) * | 1924-02-11 | 1925-07-14 | Petinot Napoleon | Method of deoxidizing open-hearth-steel baths |
| US2361627A (en) * | 1942-04-29 | 1944-10-31 | Bethlehem Steel Corp | Slag deoxidation |
| US2446759A (en) * | 1945-10-22 | 1948-08-10 | Chromium Mining And Smelting C | Open-hearth process |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2793949A (en) * | 1950-12-18 | 1957-05-28 | Imich Georges | Method of preparing composite products containing metallic and non-metallic materials |
| US2639232A (en) * | 1951-10-19 | 1953-05-19 | Ohio Ferro Alloys Corp | Addition materials for iron and steel manufacture and method of use thereof |
| US3158465A (en) * | 1961-09-07 | 1964-11-24 | Kerchner Marshall & Company | Metallurgical material and process for treating iron therewith |
| US3256085A (en) * | 1961-09-29 | 1966-06-14 | United States Steel Corp | Method of coating aluminum and adding same to molten steel |
| US3314782A (en) * | 1963-12-12 | 1967-04-18 | Fur Tech Entwicklung Und Verwe | Refining agent for steel-works |
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