US3725051A - Method of purifying low-carbon ferrochrome - Google Patents
Method of purifying low-carbon ferrochrome Download PDFInfo
- Publication number
- US3725051A US3725051A US00080811A US3725051DA US3725051A US 3725051 A US3725051 A US 3725051A US 00080811 A US00080811 A US 00080811A US 3725051D A US3725051D A US 3725051DA US 3725051 A US3725051 A US 3725051A
- Authority
- US
- United States
- Prior art keywords
- alloy
- ferrochromium
- carbon
- nitrogen
- oxygen
- 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
- 229910000604 Ferrochrome Inorganic materials 0.000 title abstract description 24
- 229910052799 carbon Inorganic materials 0.000 title abstract description 18
- 238000000034 method Methods 0.000 title abstract description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 abstract description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 15
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 13
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 12
- 229910052760 oxygen Inorganic materials 0.000 abstract description 12
- 239000001301 oxygen Substances 0.000 abstract description 12
- 238000010438 heat treatment Methods 0.000 abstract description 4
- 229910045601 alloy Inorganic materials 0.000 description 21
- 239000000956 alloy Substances 0.000 description 21
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910052804 chromium Inorganic materials 0.000 description 4
- 239000011651 chromium Substances 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000011282 treatment Methods 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910000601 superalloy Inorganic materials 0.000 description 2
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D3/00—Diffusion processes for extraction of non-metals; Furnaces therefor
- C21D3/02—Extraction of non-metals
Definitions
- This invention relates to the removal of nitrogen, carbon and oxygen from low carbon ferrochromium alloys. More particularly this invention is directed to the purification of ferrochromiurn alloys by vacuum furnacing.
- Low carbon ferrochromium alloy intended for use as an alloy addition agent to steel is produced by re acting molten chrome ore and lime with ferrochrome silicon alloy in an electric furnace to produce molten ferrochromium alloy which is thereafter cast into slabs or ingots to provide ferrochromium alloy in massive form.
- the massive alloy is subsequently crushed to suitable industrial size such as 2 inches and finer.
- the ferrochromium alloy in this form is dense, homogeneous and easily handled.
- Such alloy ordinarily contains in addition to iron and chromium, from about 0.10 to 0.13% nitrogen, 0.022 to 0.05% carbon and 0.05 to 0.12% oxygen.
- nitrogen, carbon and oxygen contents are generally undesirably high for additions to be used in the making of high performance alloy steels.
- a method in accordance with the present invention comprises heating ferrochromium metal under vacuum at elevated temperatures to provide ferrochromium containing not more than about 0.02% nitrogen, 0.01% carbon and 0.07% oxygen.
- ferrochromium alloy obtained by the solidification of molten ferrochromium for example containing 71 to 74% Cr, 25 to 28% Fe, 0.10 to 0.13% N 0.022 to 0.05% C and 0.05 to 0.12% is heated under vacuum at temperatures in the range of 1300 to 1400 C. at pressures of from 60 to 500 microns. Suitable furnacing times are from to 40 hours, preferably from 30 to 40 hours.
- the nitrogen content of the ferrochromium can be reduced to less than 0.02%, the carbon can be reduced to less than 0.01% and the oxygen can be reduced to less than United States Patent 0 0.07%.
- This result i.e. the concurrent removal of nitrogen, carbon and oxygen, is surprising and leads to the production of a highly desirable material.
- ferrochromium alloy treated in accordance with the present invention can be readily utilized in vacuum meliing operations to produce high performance alloy stee s.
- a process for lowering the nitrogen, carbon and oxygen content of particulated low carbon ferrochromium alloy which comprises heating the particulated ferrochromium at a temperature in the range of about 1300 to 1400 C. under vacuum of about 500 to 100 microns for a period of time from about 20 to 40 hours whereby a product containing not more than 0.02% nitrogen, 0.01% carbon and 0.07% oxygen is obtained.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
METHOD FOR LOWERING THE NITROGEN, CARBON AND OXYGEN CONTENT OF FERROCHROMIUM ALLOY BY HEATING THE ALLOY UNDER VACUUM.
Description
3,725,051 METHOD OF PURIFYING LOW-CARBON FERROCHROME Cecil George Chadwick, Lewiston, N.Y., assignor to Union Carbide Corporation, New York, N.Y. No Drawing. Filed Oct. 14, 1970, Ser. No. 80,811 Int. Cl. C22c 1/06, 39/14 US. Cl. 75-1305 1 Claim ABSTRACT OF THE DISCLOSURE Method for lowering the nitrogen, carbon and oxygen content of ferrochromium alloy by heating the alloy under vacuum.
This invention relates to the removal of nitrogen, carbon and oxygen from low carbon ferrochromium alloys. More particularly this invention is directed to the purification of ferrochromiurn alloys by vacuum furnacing.
Low carbon ferrochromium alloy, intended for use as an alloy addition agent to steel is produced by re acting molten chrome ore and lime with ferrochrome silicon alloy in an electric furnace to produce molten ferrochromium alloy which is thereafter cast into slabs or ingots to provide ferrochromium alloy in massive form. The massive alloy is subsequently crushed to suitable industrial size such as 2 inches and finer. The ferrochromium alloy in this form is dense, homogeneous and easily handled. Such alloy ordinarily contains in addition to iron and chromium, from about 0.10 to 0.13% nitrogen, 0.022 to 0.05% carbon and 0.05 to 0.12% oxygen. Such nitrogen, carbon and oxygen contents are generally undesirably high for additions to be used in the making of high performance alloy steels.
It is therefore an object of the present invention to provide ferrochromium alloy having very low nitrogen, carbon and oxygen contents.
Other objects will be apparent from the following description and claims.
A method in accordance with the present invention comprises heating ferrochromium metal under vacuum at elevated temperatures to provide ferrochromium containing not more than about 0.02% nitrogen, 0.01% carbon and 0.07% oxygen.
In the practice of the present invention, ferrochromium alloy obtained by the solidification of molten ferrochromium for example containing 71 to 74% Cr, 25 to 28% Fe, 0.10 to 0.13% N 0.022 to 0.05% C and 0.05 to 0.12% is heated under vacuum at temperatures in the range of 1300 to 1400 C. at pressures of from 60 to 500 microns. Suitable furnacing times are from to 40 hours, preferably from 30 to 40 hours.
As a result of the foregoing treatment, the nitrogen content of the ferrochromium can be reduced to less than 0.02%, the carbon can be reduced to less than 0.01% and the oxygen can be reduced to less than United States Patent 0 0.07%. This result, i.e. the concurrent removal of nitrogen, carbon and oxygen, is surprising and leads to the production of a highly desirable material. For example, ferrochromium alloy treated in accordance with the present invention can be readily utilized in vacuum meliing operations to produce high performance alloy stee s.
The following examples will further illustrate the present invention.
EXAMPLE I Chromium ore and lime were charged to an electric furnace. The foregoing constituents were then reacted with ferrochrome silicon to produce molten ferrochromium alloy. The molten ferrochromium alloy was teemed and cast into slabs. The massive ferrochromium alloy was subsequently crushed to obtain lumps of alloy about 2 inches in size. Approximately 15.0 lbs. of the lump ferrochromium containing about 71% Cr, 26% Fe was placed in a vacuum furnace and heated at about 1385 C. for various times up to forty hours at an absolute pressure of about 100 microns. Analysis of the alloy before and after the vacuum furnacing treatments is shown in Table I.
From the foregoing data it can be seen that after a vacuum furnacing treatment of forty hours the nitrogen content of the alloy was reduced to about one tenth of its initial value, the oxygen content was reduced to about one-half of its initial value, and the carbon content was reduced to one-fifth of its initial value.
What is claimed is:
1. A process for lowering the nitrogen, carbon and oxygen content of particulated low carbon ferrochromium alloy which comprises heating the particulated ferrochromium at a temperature in the range of about 1300 to 1400 C. under vacuum of about 500 to 100 microns for a period of time from about 20 to 40 hours whereby a product containing not more than 0.02% nitrogen, 0.01% carbon and 0.07% oxygen is obtained.
References Cited UNITED STATES PATENTS 72,541,153 2/1951 Chadwick 14s-13.1x 2,624,671 1/1953 Binder 126 3,523,021 8/1970 Khitrik 75-1305 x L. DEWAYNE RUTLEDGE, Primary Examiner I. E. LEGRU, Assistant Examiner
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US8081170A | 1970-10-14 | 1970-10-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3725051A true US3725051A (en) | 1973-04-03 |
Family
ID=22159766
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US00080811A Expired - Lifetime US3725051A (en) | 1970-10-14 | 1970-10-14 | Method of purifying low-carbon ferrochrome |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US3725051A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4260418A (en) * | 1979-09-04 | 1981-04-07 | Allegheny Ludlum Steel Corporation | Method for producing molybdenum bearing ferrochromium |
| FR2487378A1 (en) * | 1980-07-28 | 1982-01-29 | Reading Alloys | PROCESS FOR THE ALUMINOTHERMAL PRODUCTION OF CHROMIUM AND LOW NITROGEN CHROMIUM ALLOYS |
-
1970
- 1970-10-14 US US00080811A patent/US3725051A/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4260418A (en) * | 1979-09-04 | 1981-04-07 | Allegheny Ludlum Steel Corporation | Method for producing molybdenum bearing ferrochromium |
| FR2487378A1 (en) * | 1980-07-28 | 1982-01-29 | Reading Alloys | PROCESS FOR THE ALUMINOTHERMAL PRODUCTION OF CHROMIUM AND LOW NITROGEN CHROMIUM ALLOYS |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: ELKEM METALS COMPANY, A NEW YORK GENERAL PARTNERSH Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNION CARBIDE CORPORATION, A NY CORP.;REEL/FRAME:003882/0761 Effective date: 19810626 Owner name: ELKEM METALS COMPANY, 270 PARK AVENUE, NEW YORK, N Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:UNION CARBIDE CORPORATION, A NY CORP.;REEL/FRAME:003882/0761 Effective date: 19810626 |