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AssigneeNeturen Co., Ltd.
InventorsTetsukazu Hukuhara, Fumiaki Ikuta
Estimating the term…
A double tapered steel wire (S) is evenly heat treated over the entire length thereof. The wire (S) has its constant-diameter straight portion (21, 24) disposed between its opposite end tapered portions (22, 23) each tapered down to its reduced-diameter outer end. In heat treatments, a diameter of the wire (S) is continuously detected by a detection means (3, 6), so that the amount of energy of induction heating applied to the wire (S) is controlled by a control unit (12) in a manner such that the amount of the energy is proportional to a wire diameter of the wire (S) having been detected, whereby heat applied to the wire (S) varies over the entire length of the wire (S). As a result, the wire (S) is quenched and tempered over its entire length in a manner such that the wire (S) thus heat treated has its small-diameter portions (24) and its large-diameter portion (21) differ from each other in tensile strength.
A method for continuously heat treating a double tapered steel wire (S), characterized by comprising the steps of:
A double tapered steel wire (S) characterized by comprising:
An apparatus for continuously heat treating a double tapered steel wire (S), wherein the steel wire (S) is provided with a constant-diameter straight portion (21, 24) and a pair of opposite tapered portions (22, 23) disposed adjacent to opposite ends of said straight portion (21, 24), wherein said tapered portions (22, 23) are tapered down to their reduced-diameter outer ends, the apparatus being characterized by comprising:
Dependencies are inferred from the claim text.