Hardened steel with excellent chips treatability

摘要

PROBLEM TO BE SOLVED: To provide case hardening steel which has excellent treatability of chips.;SOLUTION: The case hardening steel has chemical components comprising, by mass, 0.10 to 0.30% C, 0.05 to 1.0% Si, 0.3 to 2.0% Mn, 0.003 to 0.05% S, 0.03 to 0.20% Ti, 0.005 to 0.06% Al, ≤0.03% P, ≤0.008% N and ≤0.0025% O (oxygen), and the balance Fe with impurities. The case hardening steel has a mixed structure of a ferritic phase and a bainitic phase or a mixed structure of a ferritic structure, a pearlitic phase and a bainitic phase as the microstructure of the steel, and the ratio of the bainitic phase at this time is 5 to 95% as the area fraction in the whole of the microstructure.;COPYRIGHT: (C)2005,JPO&NCIPI