Free machining steel for use in machine structure of excellent mechanical characteristics

US6579385B2 · kind B2 · utility

Assignee

• Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.) · JP

Inventors

• Hiroshi Yaguchi · Kawasaki, JP
• Yosuke Shindo · Kobe, JP
• Takehiro Tsuchida · Kobe, JP
• Takahiro Kudou · Kobe, JP
• Masato Kaiso · Kobe, JP
• Masami Somekawa · Kobe, JP

Key dates

• Filing date: Aug 17, 2001
• Grant date: Jun 17, 2003
• Expiry date: Aug 17, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C38/60
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Free machining steel for use in machine structures capable of stably and reliably providing excellent machinability (chip disposability and tool life) and mechanical characteristics (transverse direction toughness) comparable, in a Pb free state, with existent Pb-added steels the machining steel being manufactured so as to contain 0.0005 to 0.02 mass % of Mg and provide a distribution index F1 for the sulfide particles defined by the following equation (1) of 0.4 to 0.65 or a distribution index for the sulfide particles defined by the following equation (2) of 1 to 2.5:F1=X1/(A/n)½  (1), or F2=&sgr;F/X2  (2) as described in the specification.