Patent ID: 6547890
Filing Date: 2003-04-15
Classification: C21D,C22C

Abstract:
A steel wire rod for cold forging characterized by: containing, by weight,0.1 to 0.5% of C, 0.01 to 0.5% of Si, and 0.3 to 1.5% of Mn, with the balance consisting of Fe and unavoidable impurities; and having a structure mainly composed of martensite, bainite, martensite+bainite, or their tempered structure; and having a prior austenite grain size number, defined under Japanese Industrial Standard (JIS) G 0551, of 11 or higher, the amount of diffusible hydrogen in the steel measured by the programmed temperature gas chromatography being 0.2 ppm or less, and the hardness being Hv 250 to 700.