| 摘要 |
Provided are a low alloy steel for steel forgings which has yield strength and toughness required to steel forgings and has an excellent machinability. According to the present invention, the low alloy steel for steel forgings contains fundamental components such as C: 0.30wt% to 0.40wt%, Si: 0wt% to 0.45wt%, Mn: 0.50wt% to 1.90wt%, Ni: 0.70wt% to 2.00wt%, Cr: 1.00wt% to 2.30wt%, Mo: 0wt% to 0.35wt%, V: 0wt% to 0.20wt% and a remaining part of Fe and inevitable impurities, contains more than 17% of bainite microstructures, martensitic microstructures and microstructures of their combination, the remaining part is composed of pearlite microstructures, ferrite microstructures or microstructures of their combination, and satisfies the following equation (1).(1.5×Mn+2×Ni)/Cr < 2.35 ···(1) |
