US4203783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for improving the quality of steel sections
Assignee: Centre de Recherches Metallurgiques CRM ASBL
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Filing: 1978-09-18
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Granted: 1980-05-20
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Expires: 1998-09-18
Abstract
Abstract The elastic limit and breaking load of steel sections are improved by a process of surface quenching and self-tempering comprising a cooling stage followed by rapid cooling which is interrupted to allow the quenched surface layer of the section to be tempered by heat from non-quenched inner portions of the section. The rapid cooling is succeeded by a slow cooling.
Inventors
- 👤 Marios Economopoulos
- 👤 Yves J. Respen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:46
CPC Classifications
C; C21; C21D; C21D1/00; C21D1/02; C21D1/18; C21D1/19; Y; Y10; Y10S; Y10S148/00; Y10S148/902
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
167 words
A process for improving the quality of steel sections, in which, when the section leaves the rolling mill, the outer layer of a flat face of the section is subjected to a treatment of surface quenching and self-tempering, characterised in that the said treatment is carried out in three stages, in which the first stage consists of cooling such that the structure of the outer layer comprises a mixture of austenite and ferrite, the second stage consists of rapid cooling by means of a suitable cooling liquid so that the structure of the outer layer comprises a mixture of ferrite and martensite and/or bainite, this second stage being interrupted so that the non-quenched parts of the sections comprising residual austenite are at a sufficiently high temperature to permit a tempering of the quenched outer layer by the heat in the non-quenched parts, and the third stage consists of slow cooling so that the austenite in the said non-quenched parts of the section transforms into ferrite and carbides.
Claim 2
Dependent Claim
167 words
A process for improving the quality of steel sections, in which, when the section leaves the rolling mill, the outer layer of a flat face of the section is subjected to a treatment of surface quenching and self-tempering, characterised in that the said treatment is carried out in three stages, in which the first stage consists of cooling such that the structure of the outer layer comprises a mixture of austenite and ferrite, the second stage consists of rapid cooling by means of a suitable cooling liquid so that the structure of the outer layer comprises a mixture of ferrite and martensite and/or bainite, this second stage being interrupted so that the non-quenched parts of the sections comprising residual austenite are at a sufficiently high temperature to permit a tempering of the quenched outer layer by the heat in the non-quenched parts, and the third stage consists of slow cooling so that the austenite in the said non-quenched parts of the section transforms into ferrite and carbides.
Claim 3
Dependent Claim
41 words
A process according to claim 1, characterised in that the said first stage is carried out during the transfer of the section to a plant connected to the installation situated at the exit of the finishing stand of the rolling mill.
References Cited (Backward Citations)
US4016015A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-20 | 1983-11-19 | 1984-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-20 | 1987-11-19 | 1988-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-20 | 1991-11-19 | 1992-05-20 | $7700.00 | Window Closed / Lapsed |