PURPOSE: To reduce surface roughness after shot peening and to improve resistance to fatigue fracture by specifying a composition and inhibiting the formation of retained austenite after carburizing treatment.
CONSTITUTION: The steel has a composition consisting of, by weight ratio, 0.1-0.4% C, 0-0.15% Si, 0.2-1.2% Mn, 0-0.012% P, 0.005-0.07% S, 0.2-1.2% Cr, 0.015-0.1% Al, 0.005-0.025% N, and the balance Fe with inevitable impurities and satisfying the conditions of the inequality. Further, it is preferable to control O content to ≤0.002% and to added, if necessary, small amounts of Nb, Ti, V, Pb, Ca, Te, etc. This steel is formed into prescribed parts shape, carburized, and then hardened from the austenite single phase region, by which the area ratio of retained austenite in the part at a depth of 0.1mm from the surface is regulated to ≤20%.
| WO/2020/145325 | STEEL MATERIAL |
| WO/1997/002925 | GEAR SHOT PEENING METHOD AND GEAR |
| JPS6353211 | TREATMENT OF STAINLESS STEEL TUBE BODY FOR EXISTING BOILER |
ABE SATOSHI
KURAMOTO HIROSHI
YASUKI SHINICHI
