In-Situ Observation of Molten Brazing Filler Metal with New Joint Design Specimen

Abstract

Generally, brazing is completed when the brazing filler metal penetrates the gap by uniform wetting. It is believed that the joining process is completed with the formation of joint defects "voids" in the process of uniform wetting. However, previous studies have shown that what occurs when brazing is performed is non-uniform wetting. It is suggested that this non-uniform wetting is the cause of void generation.[br]In this experiment, new specimen was created. It is called us “V-groove specimen”. Specimens were created with two base metals. They are pure copper and lead-free brass in which bismuth was used as an alternative element. In order to do in situ experiments, it was not possible to observe the inside of a conventional electric furnace. Therefore, a new furnace was produced with a window for in-situ observation and experimented with it. Two types of brazing filler metals. They are BAg-7 and BAg-8. As a result of experiments with V-groove specimens, it was found that there are two types of wetting of brazing filler metal. they are called "primary wetting" and "secondary wetting". It was evaluated these two types of wetting and investigated the wetting of the brazing filler metal. It was found that the wetting of the molten brazing filler metal was different for each base metal.