Process for avoiding surface oxidation in the carburization of steels
AssigneeMesser Griesheim GmbH
InventorHans-Peter Schmidt
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Abstract
The surface oxidation under carburization temperatures of steels during the carburization with carbon-containing gas mixtures is avoided by heating the steels to the carburization temperature under a nitrogen/hydrogen mixture or pure hydrogen. For carburization, these gases are replaced by a carbon-containing gas mixture whose oxygen activity is smaller than that required for the formation of manganese(II) oxide or chromium(III) oxide.
Claims11
A process for avoiding internal oxidation in the carburization of steels with alloy elements under a carbon-containing gas mixture at the carburization temperature at atmospheric pressure, which comprises heating the steels to the carburization temperature under a hydrogen containing gas selected from the group consisting of a nitrogen/hydrogen gas mixture and a pure hydrogen gas, and carburizing with a hydrogen/hydrocarbon-containing gas mixture having an oxygen activity smaller than that required for the formation of manganese (II) oxide or chromium (III) oxide by controlling the amount of oxygen containing molecules, whereby the hydrogen/hydrocarbon-containing gas mixture makes available carbon which diffuses into the steel.
Dependencies are inferred from the claim text.