Bridgestone Metalpha Corporation

Bridgestone Corporation

Yoshikazu Kaneko

Naohiko Obana

Hideki Masubuchi

Ryuzo Osawa

Masuhiro Fujita

Toshiyuki Kobayashi

A steel wire, 0.10-0.40 mm in diameter, obtained by subjecting a high-carbon (0.70-0.90 wt. %) steel wire material to heat treatment and wire drawing, wherein its tensile strength and test values of special repeated torsional tests satisfy a predetermined relation; and a method of manufacturing the same. A high strength steel wire which has so high a ductility as to substantially prevent the wire from being broken even during wire twisting, and which rarely encounters a decrease in the ductility even after the wire has been subjected to age hardening by heating, is obtained, and a method of manufacturing the same is economical.

Steel wire and method of manufacturing the same

Corrosion resistant steel cords and pneumatic tires reinforced with same

A steel cord intended for use to reinforce rubber products is produced by drawing, into a steel filament of 0.10 to 0.40 mm in diameter and more than 3,000 N/mm.sup.2 in strength, a wire rod having a carbon content of more than 0.70% by weight, and twisting a plurality of such steel filaments together. Also a pneumatic tire is provided which employs in at least a portion of a reinforcing member thereof the steel cord improved in corrosion resistance and having an R.sub.1 /R.sub.0 ratio .times.100 which is less than 100, where R.sub.0 is the radius of spiral curvature of the spiraled steel filament resulting from untwisting said steel cord and R.sub.1 is the radius of spiral curvature of said steel filament of which the surface layer inside the spiral is removed by dissolving.

Tire having corrosion resistant steel cord

A steel cord intended for use to reinforce rubber products is produced by drawing, into a steel filament of 0.10 to 0.40 mm in diameter and more than 3,000 N/mm.sup.2 in strength, a wire rod having a carbon content of more than 0.70% by weight, and twisting a plurality of such steel filaments together. Also a pneumatic tire is provided which employs in at least a portion of a reinforcing member thereof the steel cord improved in corrosion resistance and having an R.sub.1 /R.sub.0 ratio.times.100 which is less than 100, where R.sub.0 is the radius of spiral curvature of the spiraled steel filament resulting from untwisting said steel cord and R.sub.1 is the radius of spiral curvature of said steel filament of which the surface layer inside the spiral is removed by dissolving.

Corrosion resistant steel filament

A steel cord intended for use to reinforce rubber products is produced by drawing, into a steel filament of 0.10 to 0.40 mm in diameter and more than 3,000 N/mm.sup.2 in strength, a wire rod having a carbon content of more than 0.70% by weight, and twisting a plurality of such steel filaments together. Also a pneumatic tire is provided which employs in at least a portion of a reinforcing member thereof the steel cord improved in corrosion resistance and having an R.sub.1 /R.sub.0 ration.times.100 which is less than 100, where R.sub.0 is the radius of spiral curvature of the spiraled steel filament resulting from untwisting said steel cord and R.sub.1 is the radius of spiral curvature of said steel filament of which the surface layer inside the spiral is removed by dissolving.

Growing community of inventors

Tochigi-ken, Japan

Yoshikazu Kaneko