Brazing two part air pipe for a blast furnace - using a low temp., low copper brazing metal and a low carbon steel

摘要

The front part of the pipe is exposed to the high temp. of the furnace, and so is made of copper or copper alloy, and double walled for water cooling: the rear part, however, can be of steel, which is cheaper. Satisfactory results are obtained when all the following conditions are observed si,ultaneously a low carbon (0.25% by weight) steel is heated evenly (not more than 10% between inner and outer surfaces) to 600 degrees C only, and the brazing metal used contains no more than 45% by weight of copper (plus 45% silver and some cadmium and zinc): this metal melts at 575 degrees C plus or minus 20 degrees C.