| 摘要 |
PURPOSE:To obtain cast iron for a rocker arm having superior wear resistance and scuffing resistance when lead-free gasoline or highly leaded gasoline is used by soft-nitriding cast iron contg. C, Cr, Mo and V under specified conditions of temp. and time to form a high hardness soft-nitrided layer on the surface. CONSTITUTION:Cast iron contg., by weight, 1-4% C, 1-40% Cr, 1-20% Mo and 0.1-10% V is soft-nitrided at 550-650 deg.C for >=0.5hr. A structure contg. retained austenite, martensite and/or pearlite and no graphite is provided to the matrix of the cast iron, and a high hardness compound is formed on the surface. Cast iron for a rocker arm hardly damaging a material along which the arm slides is obtd.
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