STEEL MATERIAL FOR SHEAR REINFORCING BAR WITH HIGH STRENGTH, AND WELD-CLOSED SHEAR REINFORCING BAR WITH HIGH STRENGTH

• Main Authors: TAKAHAMA TAKESHI, TAKEI MASAMITSU, IWAMOTO TAKASHI
• Format: Patent
• Language: English
• Published: 15.11.2002
• Edition: 7
• Subjects: ALLOYS; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MACHINE TOOLS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WELDING; WORKING BY LASER BEAM

PROBLEM TO BE SOLVED: To provide a weld-closed shear reinforcing bar, which has high strength, high yield strength, and equivalent or rather superior characteristics of welded parts to the base material. SOLUTION: A method for manufacturing the wire rod comprises hot-rolling steel having particular components into a linear rod with a round or deformed shape, and cooling it at a cooling rate of 0.2-50 deg.C/sec, to give it a structure consisting mainly of fine martensite. The wire rod has tensile strength of 1420 N/mm or higher, 0.2% yield strength of 1275 N/mm or higher, and butt elongation until fracture of 5% or higher, in an as-rolled state after welding.