STEEL WIRE ROD, PRODUCTION METHOD THEREFOR AND PRODUCTION METHOD FOR STEEL WIRE USING THE STEEL WIRE ROD

• Main Authors: OFUJI YOSHIHIRO, HAMADA TAKANARI
• Format: Patent
• Language: English
• Published: 25.03.2004
• Edition: 7
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS

PROBLEM TO BE SOLVED: To stably obtain a steel wire rod which has excellent cold workability and is suitable as the production stock for a steel cord or the like and an inexpensive fine-diameter high strength steel wire. SOLUTION: The steel wire rod is produced by preparing a chemical composition comprising 0.90 to 1.10% C and 0.2 to 0.6% Cr, and, if required, comprising Co and B as well, further controlling the size of pearlite blocks to No. 6 to 8 by austenite crystal grain size number, controlling the production of pro-eutectoid cementite to ≤0.2% by volume, controlling the thickness of cementite in pearlite to ≤20 nm, and controlling the concentration of Cr comprised in the cementite to ≤1.5%. The steel wire rod is produced by performing hot wire rod rolling in which heating temperature and finishing temperature are specifically controlled, and thereafter performing two stage cooling at specified cooling rates. Thus, intermediate heat treatment can be eliminated in the production of the fine-diameter high strength steel wire using the steel wire rod as the stock. COPYRIGHT: (C)2004,JPO