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Show 2 1. Introduction In the steel industry, when steel strip is heated for processing, a nonoxidizing atmosphere is used to prevent surface oxidation. A number of heating methods using radiant tubes have been often applied in continuous annealing lines, which require this type of atmospheric control. This method is an indirect type heating method where the fuel is burned inside the radiant tubes and the heat thus generated is radiated from the surface of radiant tubes for heating the strip. The average temperature of the radiant tubes needs to be brought to 950 to 1000 °C in order to quickly heat the strip up to 900 °C through radiant heating. l ) From the practical viewpoint, burners with a high combustion capacity are advantageous for mass processing because equipment costs can be reduced by adopting a compact furnace design. 2 ) Conventional radiant tubes are prone to early cracking and deformation when used at high temperature under high intensity combustion. Moreover, high intensity combustion gave rise to the problem related to the life of the burners when applied in the constricted space within the radiant tubes. The result was the problem that it was impossible to maintain low NO x and other combustion characteristics of the burners over the long term. To solve these problems, we considered a radiant tube and a burner as a single combustion system, and not, as in the past,to study the two individually. The present report describes the performance required of radiant tube burner, which was based on a thremal stress analysis of W type radiant tube deformation behavior, and on this basis, the development |