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US3855013A Expired / Lapsed US ⏱️ 0.0 years remaining

Quick heat treatment of steels

Assignee: Licencia Talalmanyokat Ertekesito Vallalat
•
Filing: 1973-03-05
•
Granted: 1974-12-17
•
Expires: 1993-03-05
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Abstract

Abstract An elongated steel workpiece is quickly heat treated in a single heat treatment, by passing it between spaced electrodes and applying a current to the steel between the electrodes thereby to heat it above the austenitic transformation temperature at a heating rate of at least 50* per second, preferably 200* to 100,000*C. per second, holding it at such annealing temperature for at most 300 seconds, preferably 0.04 to 3 seconds, so as to recrystallize the ferrite while dissolving substantially none of the carbides. The annealing temperature is no more than 85% and preferably 50-75% of the melting temperature of the steel in Kelvin degrees. The material is then quenched below the austenitic transformation temperature to prevent austenitic transformation and carbide precipitation.

Inventors

  • 👤 A Mandoki
  • 👤 J Prohaszka
  • 👤 R Welesz

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-26 10:21
CPC Classifications
C; C21; C21D; C21D8/00; C21D1/00; C21D1/34; C21D1/40

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 84 words
A PROCESS FOR THE RAPID HEAT TREATMENT OF COLD WORKED STEEL, COMPRISING HEATING THE STEEL AT THE RATE OF AT LEAST 50*C PER SECOND TO A TEMPERATURE ABOVE THE AUSTENITIC TRANSFORMATION TEMPERATURE, HOLDING THE STEEL AT SAID TEMPERATURE FOR A TIME AT MOST 300 SECONDS TO RECRYSTALLIZED THE FERRITE WITHOUT SUBSTANTIAL DISSOLUTION OF THE CARBIDES PRESENT IN THE STEEL, AND QUENCHING THE STEEL FROM SAID TEMPERATURE TO A TEMPERATURE BELOW THE AUSTENITIC TRANSFORMATION TEMPERATURE TO PREVENT THE OCCURENCE OF AUSTENITIC TRANSFORMATION AND CARBODE PRECIPITATION.
Claim 2
Dependent Claim 84 words
A PROCESS FOR THE RAPID HEAT TREATMENT OF COLD WORKED STEEL, COMPRISING HEATING THE STEEL AT THE RATE OF AT LEAST 50*C PER SECOND TO A TEMPERATURE ABOVE THE AUSTENITIC TRANSFORMATION TEMPERATURE, HOLDING THE STEEL AT SAID TEMPERATURE FOR A TIME AT MOST 300 SECONDS TO RECRYSTALLIZED THE FERRITE WITHOUT SUBSTANTIAL DISSOLUTION OF THE CARBIDES PRESENT IN THE STEEL, AND QUENCHING THE STEEL FROM SAID TEMPERATURE TO A TEMPERATURE BELOW THE AUSTENITIC TRANSFORMATION TEMPERATURE TO PREVENT THE OCCURENCE OF AUSTENITIC TRANSFORMATION AND CARBODE PRECIPITATION.
Claim 3
Dependent Claim 16 words
A process as claimed in claim 1, in which said heating rate is 200*-100,000*C. per second.
Claim 4
Dependent Claim 14 words
A process as claimed in claim 1, said time being 0.04 to 3 seconds.
Claim 5
Dependent Claim 25 words
A process as claimed in claim 1, said temperature being no more than 85% of the melting temperature of the steel measured in Kelvin degrees.
Claim 6
Dependent Claim 22 words
A process as claimed in claim 1, said temperature being 50-75% of the melting temperature of the steel measured in Kelvin degrees.
Claim 7
Dependent Claim 56 words
A process as claimed in claim 1, in which said steel is in the form of an elongated workpiece and said heating is performed by passing said workpiece between and in electrical contact with a spaced pair of electrodes, and passing a current through said workpiece between said electrodes thereby electrically resistively to heat said workpiece.

References Cited (Backward Citations)

US3271206A Cited
US3551216A Cited
US3591427A Cited
US3692591A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-12-16 1978-06-17 1978-12-17 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-12-16 1982-06-17 1982-12-17 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-12-16 1986-06-17 1986-12-17 $7700.00 Window Closed / Lapsed

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