PURPOSE: To produce easily a surface hardened steel having high hardness by bringing a steel contg. nitride forming metallic elements into contact with a cathode in a nitrogen ion atmosphere, impressing a specified voltage between the cathode and anode and executing intermittently electric discharge.
CONSTITUTION: The steel contg. nitride forming metallic elements of ≥1 kinds of Cr, Al, etc. except Fe is brought into contact with the cathode and is thus homopolarized. A gaseous mixture contg. gaseous nitrogen is introduced into a reaction vessel and the specified voltage is substantially intermittently im pressed between the above-mentioned cathode and anode in the above-mentioned reaction vessel to execute intermittently the electric discharge between the two electrodes. The nitride layer in which the nitrogen concn. in the surface is as high as 0.1W10wt% and that the decreasing gradient Δc/Δt of the nitrogen concn. (t; thickness μ, c; nitrogen concn. %) from the surface toward the inside is as small as ≤0.5 and which has ≥0.01mm thickness is formed on the steel surface. The surface hardened steel having the high hardness is thus easily and quickly obtd.
| JPH10252765 | BEARING MANUFACTURING METHOD |
| JPH09279296 | STEEL FOR SOFT-NITRIDING EXCELLENT IN COLD FORGEABILITY |
KONDO BUNJI
KUWABARA KOICHI
| JPS531141A | 1978-01-07 | |||
| JPS531143A | 1978-01-07 |
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