| 摘要 |
PROBLEM TO BE SOLVED: To provide a wire rod practically free from breaking of wire resultant from flaws caused by handling, etc., at transportation. SOLUTION: The high strength directly patenting wire rod, which has 4.0 to 16 mm diameter and in which the formation of chafing martensite in the surface layer is practically prevented by regulating Vickers hardness in the region between the surface layer and a position at a depth of 300μm from the surface layer to <=390 HV or regulating the average lamellar spacing in the region between the surface layer and a position at a depth of 300μm from the surface layer to >=95 nm, and its manufacturing method are provided.
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