| 摘要 |
PROBLEM TO BE SOLVED: To provide a hardening treatment method capable of surface layer hardening treatment of a low alloy steel having a small content of a rare metal or not containing a rare metal.SOLUTION: In a hardening treatment method of a low alloy steel, the surface of the low alloy steel is irradiated with a plasma jet of nitrogen gas containing hydrogen gas added thereto under an atmospheric pressure to heat a surface layer of the low alloy steel to an austenitic transformation point temperature or higher, and to thereby diffuse nitrogen atoms onto the surface layer of the low alloy steel; and further, the low alloy steel is hardened to generate martensitic transformation of the surface layer of the low alloy steel, to thereby generate a nitrogen martensite phase. |
