PURPOSE: To obtain a material for road surface excellent in resistances to slip, wear, and corrosion by hot rolling a cast iron sheet under the prescribed conditions and forming the square projections of prescribed shapes.
CONSTITUTION: A cast iron sheet is heated to the temperature of 950W1,050°C and is subjected to rolling reduction by 25W50% total drafts by using a roll with a single pass-groove or a flat roll with several pass-grooves, and then it is hot rolled by a roll with final pass-grooves. Thus a spheroidal graphite cast iron sheet having square or rectangular projections, each of which has a 10W50mm length of one side, a ≤5mm depth of groove, a 95W110° entering angle of groove, and a 0.2W0.4 areal ratio between the grooved part and the projecting part. This cast iron sheet is excellent in resistance to slip, wear, and corrosion and is used as a material for road surface.
TANIFUJI MINORU
SASAKI TAKESADA
