Selected heat treatment and hardening method for nails
AssigneeIllinois Tool Works Inc.
InventorsGeronimo E. Lat, Louis M. Spoto, Kent B. Godsted
Life of this patent
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Abstract
A selectively hardened nail includes a nail head, an elongated shank, and a tip. A portion of the nail shank is made harder than the remainder by selectively heat treating that portion, and cooling it. The nail has controlled bending properties. The selectively hardened portion does not significantly bend when the nail is fired at a surface using a power driving tool, or during use of the nailed object.
Claims20
A method for selectively hardening a nail, comprising the steps of:
- providing a nail including a nail head, an elongated shank and a tip, the elongated shank having a Rockwell “C” hardness of not more than about 35;
- transporting the nail to a heating assembly;
- selectively heating an upper part of the nail shank below the nail head to a temperature of at least about 1400° F.;
- and
- applying a quenching fluid to provide a selectively hardened nail.
A method for selectively hardening a nail, comprising the steps of:
- providing a nail including a nail head, an elongated shank and a tip, the elongated shank having a Rockwell “C” hardness of not more than about 35;
- transporting the nail to a heating assembly;
- selectively hardening an intermediate part of the nail shank to a temperature of at least about 1400° F.;
- and
- applying a quenching fluid to provide a selectively hardened nail.
A method of selectively hardening a nail including a nail head, an elongated shank and a tip, comprising the steps of:
- heating an axial part of the nail shank to at least about 1600° F. without so heating other axial parts of the nail shank;
- and
- quenching the axial part of the nail shank that was heated.
A method of selectively hardening a nail including a nail head, an elongated shank and a tip having a ferritic pearlitic metallurgical structure, comprising the steps of:
- selectively heating part of the nail to transform it to an austenitic metallurgical structure;
- and
- quenching the part that was selectively heated to transform it to a martensite metallurgical structure.
Dependencies are inferred from the claim text.