To provide a method for manufacturing a surface layer of reduction roll of which the material is homogeneous and which is free from any segregation looking like annual growth ring and any crude and large dendrite.
A centrifugal foundry process cats iron in a mold under the conditions as follows. If a diameter of casting iron on outer edge is more that 250 mm and less than 350 mm, a mold revolution is more than 1030 rpm and less than 1500 rpm. For the diameter is more than 350 mm and less that 500 mm, the revolution is more than 870 rpm and less that 1250 rpm. When the diameter is more than 500 mm and less than 700 mm, the revolution is more than 710 rpm and less than 1050 rpm. If the diameter is more than 900 mm, the revolution is more than 550 rpm and less than 800 rpm. Or the centrifugal foundry process casts the iron in the mold under the condition that the universal gravitation constant G on the outer periphery is more than 150 G and less than 450 G.
TSUJIMOTO YUTAKA
WADA TOSHIO
HAMAZUKA TERUO
NAKAGAWA SHINICHI
TANI TOSHIO
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