Principle of bright annealing
Bright annealing is refers to the cold rolled plate surface in a protective atmosphere without oxidation and decarburization annealing does not take. Protection of the atmosphere has a single inert gas argon or helium, also have a mixture of CO-H2-N2-CO2 (DX), N2-H2 (HNX), N2-CO2-H2 etc.. The gas mixture composition after adjustment can make the oxidation annealing process and reduction, decarburization and carburization equal speed, so as to realize the plate with no oxidation and no decarburization annealing. Annealing strip surface is not visible film, metal luster.
Bright annealing furnace according to the chemical reaction furnace gas and steel and its variation, preparation and application of protective atmosphere, determined to prevent oxidation and decarburization condition. CO2 and H2O can make the strip surface oxidation and decarbonization; CO and CH2 can make the oxidized layer reduction and steel surface carburizing; while H2 can make the oxide reduction, also can make the carbon steel surface. Oxidation of the bright annealing depends on H2O, CO2, H2 and Fe reduction reaction atmosphere. N2 and other inert gases is neutral atmosphere steel, in which N2 was used most, but must remove the oxygen atmosphere, can play a good role in protecting. Mixed atmosphere commonly used N2 and H2.
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