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US3607227A
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Production of spheroidal graphite irons
Assignee: NAT RES DEV
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Filing: 1969-01-16
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Granted: 1971-09-21
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Expires: 1989-01-16
Abstract
Abstract A method of producing spheroidal graphite irons from starting materials consisting predominantly or entirely or unselected ferrous scrap is provided. In the method, a ferrous bath is subjected to oxidation to remove or reduce to very low levels any elements inimical to spheroidization. The oxidation also reduces the carbon content of the bath to a relatively low level. Therefore, the method also includes the step of injecting powdered graphite by a carrier gas into the metal to restore the required carbon content of the iron. This method eliminates the necessity for selecting special starting materials and allows unselected ferrous scrap to predominantly or entirely comprise the ferrous charge.
Inventors
- 👤 Stephen David Stephenson
- 👤 John Holt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:26
CPC Classifications
C; C21; C21C; C21C1/00; C21C1/10; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
20 words
A process as in claim 1, wherein the ferrous bath is formed from a charge consisting predominantly of ferrous scrap.
Claim 2
Dependent Claim
14 words
A process as in claim 2, wherein the charge consists predominantly of steel scrap.
Claim 3
Dependent Claim
15 words
A process as in claim 2, wherein the charge consists of 100 percent steel scrap.
Claim 4
Dependent Claim
11 words
A process as in claim 2, wherein the scrap is unselected.
Claim 5
Dependent Claim
29 words
A process as in claim 1, wherein the deoxidizing stage is carried out after manganese in the charge has bee reduced to an acceptable level by the oxidation boil.
Claim 6
Dependent Claim
37 words
A process as in claim 1, wherein for the production of ''''alloy'''' spheroidal graphite iron, the deoxidizing stage is carried out after the charge has been sampled and, if necessary, the required amount of alloying addition made.
Claim 7
Dependent Claim
30 words
A process as in claim 1, wherein oxidation is carried out by any of the usual techniques, such as ore boiling, oxygen lancing, or the use of an oxy-fuel burner.
Claim 8
Dependent Claim
34 words
A process as in claim 1, wherein oxidation is performed by the injection with a carrier gas of a powdered oxide of a metal that is to be a constituent of the final product.
Claim 9
Dependent Claim
131 words
A process as in claim 1 wherein all the operations except making the spheroidization addition are performed in the furnace, and following oxidation and sampling for manganese and carbon, slag formed on the bath by an addition of limestone or the like and containing the products of oxidation is removed, and the bath is deoxidized by an addition of ferrosilicon, or an addition of aluminum followed by ferrosilicon, when a reducing slag is then made up, and the powdered graphite is injected by the carrier gas through a lance until the required carbon content is attained, the injection process also having the effect of creating turbulence to bring about intimate mixing of slag and metal, this aiding desulfurization following which the metal is tapped into a ladle containing the spheroidization addition.
Claim 10
Dependent Claim
13 words
A process as in claim 1, wherein the spheroidization addition is Ni Mg.
Claim 11
Dependent Claim
14 words
A process as in claim 1, wherein the spheroidization addition is FE Si Mg.
Claim 12
Dependent Claim
91 words
A process for the production of spheroidal graphite iron from a ferrous charge containing relatively large or uncontRolled amounts of elements inimical to spheroidization, which comprises the steps of: removing the inimical elements from a molten bath of the ferrous charge by oxidation, said oxidation reducing the carbon content of the bath to a relatively low or trace amount; deoxidizing and desulfurizing the bath; injecting powdered graphite into the bath by a carrier gas to restore the required carbon content of the iron; and adding a spheroidization addition to the bath.
Claim 13
Dependent Claim
18 words
The process of claim 13, wherein the ferrous charge is predominantly composed of scrap material of uncontrolled composition.
Claim 14
Dependent Claim
111 words
The process of claim 13, wherein all of the steps except adding the spheroidization addition are performed in a furnace, and which includes: sampling the bath to determine its manganese and carbon content; removing slag formed on the bath after the oxidation and sampling by an addition of limestone or the like, said slag containing the products of oxidation; applying a reducing slag to the bath; injecting powdered graphite by the carrier gas through a lance until the required carbon content is attained, the injection creating turbulence to bring about intimate mixing of the slag and metal to aid desulfurization; and tapping the metal into a ladle containing the spheroidization addition.
Claim 15
Dependent Claim
17 words
The process of claim 15, wherein the bath is deoxidized by adding a ferrosilicon to the bath.
Claim 16
Dependent Claim
19 words
The process of claim 15, wherein the bath is deoxidized by adding aluminum followed by ferrosilicon to the bath.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |