摘要 |
<p>This steel for induction hardening contains, by percent by mass, C: 0.7 to 0.9%, Si: 0.4 to 1.0%, Mn: 0.5 to 1.25%, P: 0.030% or less, S: 0.030% or less, Cr: 0.4% or less, Al: 0.05% or less, Ti: 0.003% or less, and O: 0.0020% or less, wherein [Mn]≰0.5+0.35/[Si] is met, the steel further contains Fe and unavoidable impurity and the steel has annealing hardness of 93 HRB or less, and wherein an induction hardening layer after induction hardening has residual austenite of 20 to 40% and hardness of 61 HRC or more. This makes it possible to provide steel for induction hardening in which lowering of a fatigue life hardly occurs even though foreign objects incorporates into lubricating oil of a motion guide device and concentration of stress on its dent causes flaking due to lubrication failure to be generated on a steel surface of a device, or even though rolling/sliding contact occurs.</p> |