High-durable pneumatic radial tires
AssigneeBridgestone Corporation
InventorsTakao Ogino, Yoichi Watanabe, Shigehisa Sano
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Abstract
A high-durable pneumatic radial tire is disclosed using steel cords in at least one of the carcass and the belt. This steel cord is produced by twisting plural steel filaments each having a tensile strength of not less than 220 kgf/mm.sup.2, whose metallic structure being a fine pearlite structure having an average value of interlamellar distance between cementites of 300-500 .ANG. and an average sectional area of single pearlite crystal grain in filament section of not more than 20 .mu.m.sup.2.
Claims2
A high-durable pneumatic radial tire comprising a tread portion, a pair of side portions extending from the tread portion, a pair of bead portions extending from the side portions, and a carcass reinforced with a belt embedded in the tread portion, in which steel cords are used in at least one of the carcass and the belt, characterized in that said steel cord is produced by twisting plural steel filaments each having a tensile strength of not less than 220 kgf/mm.sup.2, whose metallic structure being a fine pearlite structure having an average value of interlamellar distance between cementites of 300-500 .ANG. and an average sectional area of single pearlite crystal grain in filament section of not more than 20 .mu.m.sup.2.
Dependencies are inferred from the claim text.