Honda Motor Co., Ltd.

Dowa Thermotech Co., Ltd.

Nippon Steel Sumitomo Metal Corporation

Masao Kanayama

Atsushi Kobayashi

Susumu Maeda

Kiyotaka Akimoto

Yuichiro Shimizu

Masato Yuya

Hideki Imataka

Yuya Gyotoku

A manufacturing method of a nitrided steel member and the nitrided steel member include: performing a nitriding treatment on a steel member made of a carbon steel or an alloy steel in an atmosphere of a nitriding treatment gas in which when the total pressure is set to 1, a partial pressure ratio of NHgas is set to 0.08 to 0.34, a partial pressure ratio of Hgas is set to 0.54 to 0.82, and a partial pressure ratio of Ngas is set to 0.09 to 0.18, at a flow speed of the nitriding treatment gas set to 1 m/s or more, at 500 to 620&#xb0; C.; and thereby, forming an iron nitride compound layer having a thickness of 2 to 17 &#x3bc;m on a surface of the steel member.

Manufacturing method of nitrided steel member

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 IFeN (111) of a (111) crystal plane of FeN and X-ray diffraction peak intensity IFeN (111) of a (111) crystal plane of FeN, which are measured on a surface of the nitrided steel member by X-ray diffraction, an intensity ratio expressed by IFeN (111)/{IFeN (111)+IFeN (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 &#x3bc;m.

Nitrided steel member and manufacturing method thereof

The present invention provides a nitrided steel member and manufacturing method thereof. the nitrided steel member including: an iron nitride compound layer formed on a surface of a steel member made of carbon steel for machine structural use or alloy steel for machine structural use, in which with regard to X-ray diffraction peak intensity IFeN (111) of the (111) crystal plane of FeN and X-ray diffraction peak intensity IFeN (111) of the (111) crystal plane of FeN obtained by measuring a surface of the nitrided steel member by X-ray diffraction, an intensity ratio represented by IFeN(111)/{IFeN (111)+IFeN (111)} is 0.5 or more, and a thickness of the iron nitride compound layer is 2 to 17 &#x3bc;m.

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Tokyo, Japan

Masao Kanayama