To avoid surface defects in an annealing material, as protective gas, by using rare gas pure as much as possible in such a manner that it is acted cooperatively with an oxygen bonding body.
Preferably, for subjecting metal adhered with a remaining lubricant to bright annealing, the lubricant is evaporated under protective gas composed of rare gas or inert gas and/or reducing gas, and, as protective gas for the subsequent bright annealing, rare gas mixed with ≤50 vol.% reducing gas and pure as much as possible is used in such a manner that it is acted cooperatively with an oxygen bonding body. As the protective gas, pure rare gas such as argon, neon or the like is used in such a manner that it is acted cooperatively with an oxygen bonding body, advantageously with Ti. By using the protective gas together with the oxygen bonding body in an annealing case, the reaction accompanying the oxidation or discoloration is checked by an oxygen carrier such as CO, CO2, H2O or the like or oxygen. Moreover, the transport of the oxygen and oxygen carrier from a heat resistant material of the annealing case to the annealing material is generally blocked.
LOCHNER HERIBERT
LOCHNER HERIBERT
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