HIGH-STRENGTH ULTRAFINE STEEL WIRE WITH EXCELLENT WORKABILITY IN STRANDING, AND PROCESS

摘要

A high-strength ultrafine steel wire with excellent workability in stranding, which comprises, by weight, 0.85 to 1.10 % of carbon, 0.10 to 0.70 % of silicon, 0.20 to 0.60 % of manganese, 0.10 to 0.60 % of chromium, 0.005 % or less of aluminum, and further, if necessary, 0.10 to 2.00 % of nickel or/and 0.10 to 3.00 % of cobalt, and the balance of iron and inevitable impurities; is provided with a brass plating layer; and has a diameter of 0.1 to 0.4 mm, a tensile strength of 400 kgf/mm² or above, a depth of an indentation on the surface of the brass plating layer of 2 µm or less, a distance between the indentations of 50 µm or less and an area rate of the indentations of 10 to 80 %. A process and an apparatus for producing said wire by subjecting the material of the steel wire to patenting, brass plating and drawing, followed by shot peening of air blasting type under tensions.