Patent ID: 6949149
Filing Date: 2005-09-27
Classification: C21D,C22C,D07B

Abstract:
1. A process for forming a drawn wire, comprising a) casting and rolling of a steel to form a wire of an initial diameter, said steel comprising iron and the following components in percent by weight: 0.95%≦carbon≦1.3%, 0.2%≦chromium≦1.8%, 0.2%≦manganese≦0.8% 0.2%≦silicon≦1.2% cobalt≦2.2% niobium≦0.1% 0.0006 parts per million (ppm)≦boron≦0.0025 pm sulfur<0.006% phosphorus<0.010%; b) rough drawing of the wire to reduce the diameter of the wire to an intermediate diameter; c) patenting the wire to obtain a predominantly pearlitic microstructure with a small globular size having an elongation greater than 7.5%, with the predominantly pearlitic microstructure providing a tensile strength determined by the following equation: where: A  C=the carbon content of the steel, in %,  C  L=the thickness of ferrite lamellae,  Y  H=the strain hardening of the wire, and  ε=the total elongation of the wire; d) brass plating and fine drawing the wire to reduce the wire to a final diameter of about 0.1 to about 0.4 mm with a true strain from 3.6 to 4.5 to obtain an ultimate tensile strength determined by the following equation: where A