PURPOSE: To reduce the roll consumption unit by welding the outer shell layer and the inner layer to one body, crystallizing the graphite in the composition of outer shell layer and making the specific property to the outer shell layer.
CONSTITUTION: The outer shell layer 2 and the inner layer of the high chromium cast iron roll 1 are welded to one body. And also, the graphite is crystallized in the composition of outer shell layer 2, and the outer shell layer is made to the inequality I. On the inequality I, da/dN; the fatigue crack propagating speed (mm/cycle), K; stress enlarging coefficient (kg/mm2/3). The chemical component of the outer shell layer is, by weight, 2-3.5% C, 1-2.2% Si, 0.5-1% Mn, 4-10% Ni, 5-10% Cr, 0.1-5% Mo, the balance Fe practically. Therefore, a small crack can be prevented from growing to a deep crack.
HATTORI TOSHIYUKI
MAYAMA KAZUNARI
OHATA TAKUMI
NAWATA RYOSAKU
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