BRAZING Q&A A: In simple terms, the dew point is the temperature at which the gas becomes saturated with moisture. For most brazing operations, the dew point must be –60°F/–50°C or colder to achieve good brazes. You are quite correct to be concerned about a high dew point since excess moisture in the gas can ruin your work. A sometimes overlooked aspect of the furnace brazing system is the piping that delivers the gaseous atmosphere to the furnace. Often, the piping 30 WELDING JOURNAL / APRIL 2015 BY DAN KAY Q:We pipe gaseous atmosphere into our brazing furnace from a liquid argon tank located in the company’s back lot. The problem is the dew point we measure for the gas at the furnace is too high. Our gas supplier claims the liquid storage tank and equipment are not causing this problem. Why is the dew point so poor and what can we do to get drier gas at the furnace? Fig. 1 — A liquid gas storage installation with exposed piping. For info, go to www.aws.org/adindex
Welding Journal | April 2015
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