To provide a high carbon steel sheet which is excellent in blanking workability and hardenability thereafter, in which the amount of undissolved carbide and the grain size distribution thereof can easily be controlled by quenching/tempering treatment, and which can produce a component improved in fatigue properties in addition to toughness.
An annealed steel sheet has a constitution containing, by mass, 0.50 to 0.70% C, 0.5% Si, 1.0 to 2.0% Mn, 0.02% P, 0.02% S and 0.001 to 0.10% Al, and further containing one kind or two kinds or more selected from 0.05 to 0.50% V, 0.02 to 0.20% Ti and 0.01 to 0.50% Nb, and having a structure where the spheroidizing ratio of carbides is 95%, and further, carbides with the maximum particle diameters of 2.5 m are dispersed.
TAKEDA KIMIYOSHI
TAGASHIRA SATOSHI
SUZAKI TSUNETOSHI
