Composite rubber bodies using steel cords for the reinforcement of rubber articles

A composite rubber body formed by embedding steel cords in rubber and vulcanization-building them, each of the cords comprises plural twisted steel filament wires obtained by dry-drawing a wire rod of high carbon steel comprising C:

• 0.78 wt %, Si:
• 0.10-0.30 wt %, Mn:
• 0.30-0.55 wt % and the remainder being iron and inevitable impurities, subjecting the drawn filament to a patenting treatment and wet-drawing to a given diameter, in which all of the filament wires satisfy relationships of the following equations (1) and (2):
• T.sub.1 .gtoreq.230-148logD (1)
• T.sub.2 .gtoreq.235-148logD (2)
• wherein D is a diameter (mm) of the filament wire and T.sub.1 is a tensile strength (kgf/mm.sup.2) before the vulcanization and T.sub.2 is a tensile strength (kgf/mm.sup.2) after the vulcanization, and have a retention of loop strength of not less than 55%.