STEEL FOR BELT-TYPE CVT PULLEY AND THE BELT-TYPE CVT PULLEY

摘要

PROBLEM TO BE SOLVED: To provide a steel for a belt-type CVT pulley exhibiting a deformation resistance during hot forging equal to or lower than that of the conventional material while improving a wear resistance and a fatigue strength compared with the conventional material.SOLUTION: A steel for a belt-type CVT pulley consists of chromium steel or chromium-molybdenum steel with a composition satisfying a predetermined formula for mass percentages of Mn, Ni, Cr, Mo, Si, Nb, and Ti. The steel includes, by mass% and as indispensable additive elements, 0.15-0.25% C, 0.40-1.00% Mn, over 1.8% to 2.20% Cr, 0.005-0.03% N, and 0.010-0.060% Al. The steel also includes the composition including, as optional additive elements, 0.20% or less Si, 0.03% or less P, 0.05% or less S, 0.3% or less Cu, 0.3% or less Ni, and 0.2% or less Mo, with the balance being Fe and inevitable impurities.