Research on the Atmosphere in the Annealing Furnace for Cold Rolled Galvanizing
The atmosphere inside the annealing furnace of a continuous hot continuous galvanizing line is composed of a reducing protective gas composed of nitrogen and hydrogen.It plays a role in protecting the strip steel,preventing oxidation,and reducing the surface oxide of the strip steel to increase the wettability of the galvanizing process.The quality of the atmosphere inside the furnace is an important factor determi-ning the adhesion of the zinc layer.This article focuses on the proportion and detection of various atmosphere components in the furnace,as well as the effects of nitrogen content,hydrogen content,oxygen content,and dew point on the strip steel in the heating furnace and their im-pact on the quality of the strip steel.A reasonable atmosphere proportion can achieve a balance between protecting the strip steel and reducing impurities;Analyze the reasons for the deterioration of the atmosphere inside the furnace,and introduce the inspection,treatment methods,and preventive measures for the airtightness of the annealing furnace based on production practice;According to the different process require-ments of each process section of the heating furnace,different atmosphere ratios are adopted,especially the control of dew point.The dew point of the heating section can reflect the reducing ability of the protective gas to a certain extent,while the control of dew point in the grate section mainly suppresses the production of zinc ash.Zinc ash adhering to the surface of the strip steel will form quality defects such as zinc spots and bright spots,seriously affecting the surface quality of the strip steel and reducing the quality level of the plate.High end car exterior panels have very strict requirements for surface quality,so a good furnace atmosphere is an important guarantee for producing high-end car panels.
cold rolling and galvanizingatmosphere controlatmospheredew point