DEVELOPMENT OF GALVANIZED HIGH-STRENGTH HIGH-CARBON STEEL WIRE.

Abstract

High-carbon steel wire rods with a composition of 0. 85 wt% C, 1. 19 wt% Si and 1. 19 wt% Mn were given a lead patenting treatment. The result shows that the steel wire rod has a tensile strength higher than that of plain high-carbon steel rod by 17 kgf/mm**2. Then, the wire rod was drawn by the direct cooling drawing system to prevent strain aging. Based on these experimental results, high-strength large diameter galvanized steel wires with nominal diameters of 5, 6, and 7 mm were trially manufactured. The mechanical properties of the new Si-Mn galvanized steel wires were experimentally proved to be 20 to 30 kgf/mm**2 higher in tensile strength and 7 to 10 kgf/mm**2 higher in fatigue strength than plain high-carbon galvanized steel wires. There was no perceivable deterioration in toughness, and the relaxation value after 10 hr was only one-third of that of the high-carbon galvanized steel wires. Thus, the newly-developed high-strength Si-Mn galvanized steel wires were proved to be suitable for use as cable wires for long span suspension bridges and other purposes.