US4227924A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of vermicular cast iron
Assignee: Microalloying International Inc
•
Filing: 1978-05-18
•
Granted: 1980-10-14
•
Expires: 1998-05-18
Abstract
Abstract Process for producing vermicular cast iron comprising: (i) forming a near eutectic melt having a sulfur content preferably less than about 0.025% by weight; (ii) admixing at least one rare earth-containing additive with said melt to form stable rare earth oxysulfides thereby reducing and maintaining the Henrian sulfur activity in the melt at between about 0.004 and 0.035; and (iii) thereafter, allowing said melt to solidify.
Inventors
- 👤 Sundaresa V. Subramanian
- 👤 Debabrata S. Ghosh
- 👤 John M. Gray
- 👤 David A. R. Kay
- 👤 Gary R. Purdy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:10
CPC Classifications
C; C21; C21C; C21C1/00; C21C1/02; C21C1/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
62 words
Process for producing vermicular cast iron comprising: (i) forming a near eutectic melt having a sulfur content less than 0.025% by weight; (ii) admixing at least one rare earth-containing additive with said melt to form stable rare earth oxysulfides thereby reducing the Henrian sulfur activity in the melt to between about 0.004 and 0.035; and (iii) thereafter allowing said melt to solidify.
Claim 2
Dependent Claim
62 words
Process for producing vermicular cast iron comprising: (i) forming a near eutectic melt having a sulfur content less than 0.025% by weight; (ii) admixing at least one rare earth-containing additive with said melt to form stable rare earth oxysulfides thereby reducing the Henrian sulfur activity in the melt to between about 0.004 and 0.035; and (iii) thereafter allowing said melt to solidify.
Claim 3
Dependent Claim
60 words
The process of claim 1 wherein the near eutectic melt has a composition comprising about 3.0 to 4.5% by weight carbon; about 1.0 to 3.5% by weight silicon; up to about 1.2% by weight manganese, less than about 0.1% by weight phosphorus and the balance being iron, said iron composition being capable of solidifying to gray iron in untreated condition.
Claim 4
Dependent Claim
36 words
The process of claim 1 additionally comprising the step of first desulfurizing the melt from a sulfur content of above about 0.025% by weight to a sulfur content of from about 0.01 to 0.02% by weight.
Claim 5
Dependent Claim
28 words
The process of claim 1 wherein sufficient rare earth-containing additive is admixed with the melt to reduce the Henrian sulfur activity therein to between about 0.0075 to 0.0265.
Claim 6
Dependent Claim
23 words
The process of claim 1 wherein from about 0.5 to 6 pounds of rare earth metal are added per ton of molten iron.
Claim 7
Dependent Claim
21 words
The process of claim 1 wherein from about 0.02 to about 0.04 wt.% of aluminum is additionally added to the melt.
Claim 8
Dependent Claim
22 words
The process of claim 1 wherein the melt is inoculated with from about 0.5 to 1 wt.% of melt weight of ferrosilicon.
Claim 9
Dependent Claim
34 words
The process of claim 1 wherein the silicon content of the melt ranges from about 2.0 to 3.5% by weight and the resulting cast iron is further characterized by essential freedom from eutectic carbides.
Claim 10
Dependent Claim
44 words
The process of claim 7 wherein the melt is inoculated with sufficient ferrosilicon to bring the silicon concentration of the melt into the range of 2.0 to 3.5% by weight and the resulting cast iron is further characterized by essential freedom from eutectic carbides.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-14 | 1984-04-14 | 1984-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-14 | 1988-04-14 | 1988-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-14 | 1992-04-14 | 1992-10-14 | $7700.00 | Window Closed / Lapsed |