Determination of spreading and flow behavior of brazing fillers

Abstract

The development of new brazing fillers requires knowledge about their properties in comparison to well established fillers. Therefore, the determination of the spreading and flow behavior is necessary. By now, different measuring techniques are combined in order to reach a comprehensive understanding of the mechanisms. Especially in case of flux brazing, conventional measuring techniques cannot be used. Due to the industrial demand of application-related experiments, the intended setup should be simple and easily to arrange. This paper deals with the development of a new procedure to determine the spreading and flow behavior of brazing fillers employing flux. The experimental setup, which consists of a commercially available induction heater, equipped with a temperature controller, is mounted inside a gas and vacuum tight chamber. A CCD camera system is used to record the spreading and flow behavior on surfaces as well as inside narrow gaps. The results of experiments using different fillers and base materials are presented. The measurements of the spreading area and the flow velocity under defined conditions allow a quantitative evaluation of the properties of the fillers. Thus, the comparison of different fillers among each other is possible.

Keywords

• spreading
• flow
• brazing