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

摘要

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°C/sec, to give it a structure consisting mainly of fine martensite. The wire rod has tensile strength of 1420 N/mm² or higher, 0.2% yield strength of 1275 N/mm² or higher, and butt elongation until fracture of 5% or higher, in an as-rolled state after welding.;COPYRIGHT: (C)2003,JPO