| 摘要 |
A nitrided steel member including an iron nitride compound layer formed on a surface of a steel member having predetermined components, wherein: in X-ray diffraction peak intensity IFe4N (111) of a (111) crystal plane of Fe4N and X-ray diffraction peak intensity IFe3N (111) of a (111) crystal plane of Fe3N, which are measured on a surface of the nitrided steel member by X-ray diffraction, an intensity ratio expressed by IFe4N (111)/{IFe4N (111)+IFe3N (111)} is 0.5 or more; Vickers hardness of the iron nitride compound layer is 900 or less, Vickers hardness of a base metal immediately under the iron nitride compound layer is 700 or more, and a difference between the Vickers hardness of the iron nitride compound layer and the Vickers hardness of the base metal is 150 or less; and a thickness of the iron nitride compound layer is 2 to 17 μm. |
| 主权项 |
1. A nitrided steel member comprising an iron nitride compound layer formed on a surface of a steel member
which contains, by mass %, C: 0.05 to 0.14%, Si: 0.10 to 0.30%, Mn: 0.4 to 1.4%, Cr: 0.9 to 1.9%, Mo: 0 to 0.50%, V: 0 to 0.40%, Al: 0.01 to 0.14%, and S: 0.005 to 0.030%, whose Hs value expressed by the following expression 1 is 1.19 or more, whose Hc value expressed by the following expression 2 is 3.76 or less, and in which the balance is made of Fe and impurities, with P, N, and O in the impurities being P: 0.030% or less, N: 0.008% or less, and O: 0.0030% or less, wherein, in X-ray diffraction peak intensity IFe4N (111) of a (111) crystal plane of Fe4N and X-ray diffraction peak intensity IFe3N (111) of a (111) crystal plane of Fe3N, which are measured on the surface of the nitrided steel member by X-ray diffraction, an intensity ratio expressed by IFe4N (111)/{IFe4N (111)+IFe3N (111)} is 0.5 or more, wherein Vickers hardness of the iron nitride compound layer is 900 or less, Vickers hardness of a base metal immediately under the iron nitride compound layer is 700 or more, and a difference between the Vickers hardness of the iron nitride compound layer and the Vickers hardness of the base metal is 150 or less, and wherein a thickness of the iron nitride compound layer is 2 to 17 μm.
Hs value=(−342.1×C+23.5×Mn+125.0×Cr+14.4×Mo+208.3×V+346.4×Al)/100 expression 1 In the expression 1, C, Mn, Cr, Mo, V, and Al represent values of mass % of the respective elements.
Hc value=(156.1×C+54.7×Mn+158.4×Cr+146.5×Mo+33.8×V+418.6×Al)/100 expression 2 In the expression 2, C, Mn, Cr, Mo, V, and Al represent values of mass % of the respective elements. |
