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US 4,375,378 AGranted
Process for producing spheroidized wire rod
AssigneeNippon Steel Corporation
InventorsSaburo Ohtani, Toshimichi Mori, Soichi Izumi
Life of this patent
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Abstract
A process for producing a wire rod for cold forging comprising: rapidly cooling the wire rod after hot rolling so as to give a rapidly cooled structure to the wire rod and to form a predetermined thickness of scale on the wire rod; and subjecting the rapidly cooled wire rod with the scale to spheroidizing annealing in an inert gas containing 0.1% or less moisture.
Claims3
A process for producing a cold forging steel wire rod having a reduced decarburized layer thickness on the surface and excellent cold forgeability consisting essentially of:
- hot rolling a steel wire rod and permitting the hot rolled wire rod to stand for at least 8 seconds to form a layer of scale having a thickness of at least 8 microns on the surface of the rod;
- quenching the hot rolled wire rod at a cooling rate of at least 4.degree. C./sec. to produce a rapidly cooled structure composed of sorbite and/or bainite as well as a small amount of incidental martensite;
- and
- spheroidizing annealing said rod in an inert gas having a moisture content of about 0.04 to about 0.1%.
1 more element
Dependencies are inferred from the claim text.