Kobe Steel, Ltd.

Tomonobu Ishida

Nao Yoshihara

Shuhei Kitamura

A technique with which air blast cooling can be used to produce a high-strength steel wire material that achieves uniform high strength and high ductility, even when cold drawn; a high-strength steel wire produced from this high-strength steel wire material; and a zinc-plated high-strength steel wire. This high-strength steel wire material includes 0.80-1.3% of C, 0.1-1.5% of Si, 0.1-1.5% of Mn, more than 0% but not more than 0.03% of P, more than 0% but not more than 0.03% of S, 0.0005-0.01% of B, 0.01-0.10% of Al, and 0.001-0.006% of N, the remainder being iron and unavoidable impurities. The area ratio of pearlite in the structure of the high-strength steel wire material is at least 90%. The average grain size number (P) of pearlite nodules and the standard deviation (P&#x3c3;) thereof respectively satisfy formula (1), namely 7.0&#x2266;P&#x2266;10.0, and formula (2), namely P&#x3c3;&#x2266;0.6.

High-strength steel wire material exhibiting excellent cold-drawing properties, and high-strength steel wire

Provided are: a steel wire rod material for a high-strength spring, which does not undergo the increase in deformation resistance arising from the increase in hardness and can exhibit good wire-drawing processability and the like even when a heat treatment, which deteriorates productivity, is eliminated or a simplified and rapid heat treatment is employed instead; a useful method for producing the steel wire rod material for a high-strength spring; a high-strength spring produced using the steel wire rod material for a high-strength spring as a material; and others. This steel wire rod material for a high-strength spring is a steel wire rod material that has been hot-rolled already, and has a texture having a specified chemical composition and mainly composed of pearlite, wherein the average value (Pave) of the pearlite nodule size numbers and the standard deviation (P&#x3c3;) of the pearlite nodule size numbers fulfill the following formulae (1) and (2), respectively:9.5&#x2266;ave&#x2266;12.0;&#x2003;&#x2003;(1)and0.2&#x2266;&#x3c3;&#x2266;0.7&#x2003;&#x2003;(2).

Growing community of inventors

Kobe, Japan

Tomonobu Ishida