VERFAHREN ZUR VERMEIDUNG VON KLEBERN UND KRATZERN BEIM REKRISTALLISATIONSGLÜHEN VON KALTBAND

摘要

According to a known method for avoiding adhesions and scratches during recrystallization annealing of cold rolled strips in bell-type furnaces, which comprises the phases of heating, maintaining and cooling, the cold rolled strip is subjected during the maintaining phase to an atmosphere with an oxidizing partial pressure P(CO2)/P(CO) >1, adjusted by admixing an oxidant to the protective furnace gas. In order to improve the known method with respect to its reproducibility of avoiding adhesions during the annealing of cold rolled strips under a protective atmosphere with gases having a high hydrogen content (>5%), without the formation of thick, oxidic cover layers required. The oxidant is added together with unburnt gas that contains carbon dioxide in a concentration of maximally 40 % by volume and hydrogen. The partial pressure ratio of the water and hydrogen formed in the furnace atmosphere is determined and controlled.