Method for treating surface of ferrous material and salt bath furnace used therefor
AssigneeMaizuru Corporation
InventorsIsao Miyagi, Wataru Taniguchi
Life of this patent
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Abstract
The present invention features nitriding-treating the ferrous material to form a nitrided layer composed of at least one of iron nitride and iron carbide nitride on the surface thereof, and heating to maintain the ferrous material at a temperature of 500 to 700° C. in a treating agent (A), whereby chromium is diffused into the nitrided layer to form a compound layer composed of at least one of chromium nitride and chromium carbide nitride, wherein the treating agent (A) contains the following (a) as a main component and containing the following (b) and (c): (a) at least one of alkali metal chloride and alkaline earth metal chloride; (b) glass having silicone oxide as a main component; and (c) chromium.
Claims10
A method for treating a surface of a ferrous material, which comprises:
- nitriding-treating the ferrous material to form a nitrided layer composed of at least one of iron nitride and iron carbide nitride on the surface thereof, and heating to maintain the ferrous material at a temperature of 500 to 700° C. in a molten salt bath of a treating agent (A), whereby chromium is diffused into the nitrided layer to form a compound layer composed of at least one of chromium nitride and chromium carbide nitride,
- wherein the treating agent (A) contains the following (a) as a main component and containing the following (b) and (c):
- (a) at least one of alkali metal chloride and alkaline earth metal chloride;
- (b) glass having silicone oxide as a main component;
- and
- (c) chromium.
A method for treating a surface of a ferrous material, which comprises:
- nitriding-treating a ferrous material to form a nitrided layer composed of a nitrogen-diffused layer on the surface thereof and heating to maintain the ferrous material at a temperature of 500 to 700° C. in a molten salt bath of a treating agent (A), whereby chromium is diffused into the nitrided layer to form a chromium-concentrated layer, wherein the treating agent (A) contains the following (a) as a main component and containing the following (b) and (c):
- (a) at least one of alkali metal chloride and alkaline earth metal chloride;
- (b) glass having silicone oxide as a main component;
- and (c) chromium.
Dependencies are inferred from the claim text.