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US3668024A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of annealing metal powder

Assignee: AO Smith Inland Inc
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Filing: 1969-10-07
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Granted: 1972-06-06
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Expires: 1989-10-07
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Abstract

Abstract THE INVENTION RELATES TO A PROCESS FOR ANNEALING STEEL POWDER. THE POWDER IS CONTINUOUSLY PASSED THROUGH AN ANNEALING FURNACE AND HEATED TO A TEMPERATURE IN THE RANGE OF 1450*F. TO 2100*F. WHILE EXPOSED TO A REDUCING GAS. THE DEW POINT OF THE FURNACE ATMOSPHERE IS MAINTAINED AT A VALUE SLIGHTLY BELOW THE EQUILIBRIUM VALUE THROUGHOUT THE LENGTH OF THE HEATING ZONE BY ADJUSTMENT OF THE RATE OF FLOW OF THE REDUCING GAS TO THE FURNACE. BY MAINTAINING THE DEW POINT OF THE FURNACE ATMOSPHERE WITHIN PRECISE LIMITS, A SUBSTANTIALLY COMPLETE REDUCTION OF THE CARBON CONTENT OF THE STEEL PARTICLES IS OBTAINED AND WELDING OF THE PARTICLES IS PREVENTED, SO THAT THE SINTERED CAKE OF PARTICLES CAN BE READILY BROKEN UP AFTER ANNEALING TO RESTORE THE AS-ATOMIZED PARTICLE SIZE AND THEREBY PROVIDE AN INCREASE DENSITY FOR THE COMPACTED AND SINTERED PART.

Inventors

  • 👤 Milton Johnson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 15:11
CPC Classifications
B; B22; B22F; B22F1/00; B22F1/14; B22F1/142

Claims Analysis

Total Claims: 0
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References Cited (Backward Citations)

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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) 1975-06-06 1975-12-06 1976-06-06 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-06-06 1979-12-06 1980-06-06 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-06-06 1983-12-06 1984-06-06 $7700.00 Window Closed / Lapsed

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