銀ろうによる黄銅ろう付部の脱亜鉛現象とミクロ組織

抄録

Brass is mainly used for piping components, etc. However, the Drinking Water Quality Standards Law restricted the amount of lead added. Lead–free brass was developed by adding Bi and Si as alternative elements. Brazing is also essential as a joining technology when used for piping components. Dezincification is generally associated with dezincification corrosion that occurs in a liquid solution. However, dezincification of brass also occurs during heat treatment, when the high vapor pressure of zinc causes zinc to desorb from the base metal. It has been shown that the zinc in the brass is dislodged, leaving only copper with cavities. As a result, the performance of the brazed body may be impaired.

Currently, methods to prevent dezincification that occurs during brazing heat addition include lowering the brazing temperature and brazing under a zinc vapor atmosphere. Also, from past papers, there have been few studies on dezincification of brasses coexisting in two phases, α–phase and β–phase. Therefore, the purpose of this study is to investigate the effect of heat treatment on the phenomenon of dezincification and to study in detail the effect of dezincification on the microstructure of brazed brass parts.