Method for high carbon wire rod containing high silicon to reducing decarburization depth of its surface

摘要

The present invention relates to a method for producing a wire rod to be used is processed into a bolt or the like, it is an object of the river the graphitization treatment for cold formability improvement possible, the carbon employed in the surface of the billet also forms a lower ferrite layer of silicon the amount added to provide a method of manufacturing the wire capable of reducing the surface decarburized layer generated according to High. ; The present invention for achieving the above object, in weight percent, carbon: 0.65-1.50%, 2.0-4.0% silicon, 0.1-0.8% manganese, phosphorus and sulfur than 0.01%, 0.002-0.01% of nitrogen, oxygen, 0.002% or less containing, and thereto 0.3-2.0% nickel, boron 0.001-0.003%, V: 0.01 to 0.5%, niobium: 0.01 to 0.5%, 0.01-0.5% Mo, 0.01-0.2% Ti, 0.01-0.5% tungsten, copper selected one or more from the group of 0.01-0.2%, balance of Fe and other impurities into the re-heated bloom the range of 1260 ± 100 ± 20 minutes in the range of 30 ℃ composition is a billet by rolling and ferrite decarburized layer on the surface gaining the formed billet, the high maintenance by raising the temperature of the billet at the heating temperature of 1100 ± 50 ℃ at a heating rate above the average 10 ℃ / min 45 ± 15 min, was added and small surface decarburization depth characterized in that the wire rod rolled silicon and to a method of manufacturing a steel wire as the technology base. ; High-strength bolt, cold formability, wire, surface decarburization, high carbon