In Situ Evaluation of the Joining Defects in a Pb-Free Soldered Joint

Abstract:

Conventionally, brass has toughness more than other metals, so there is a concern about its poor machinability. Therefore, improvement of machinability was attempted by adding lead to brass. This brass called free cutting brass, typified by JIS C3771. This free-cutting brass is used for piping components and machine parts. There is a concern about elution of the lead into drinking water. Hence, Drinking Water Quality Standards Law has been amended and it restricts lead content in the free cutting brass. Therefore, lead-free free-cutting brass with no lead or minimized content of lead is required.Consequently, a lead-free free-cutting brass had been developed to improve in machinability such as JIS C6931 and JIS C6803 that are added Si and Bi instead of lead respectively. Lead was also used for the solder for joining among pure copper pipes and brass valves. That causes elution of lead from the solder into drinking water. For this reason, Lead-free solder such as Sn-Sb and Sn-Ag-Cu have been used.A fire torch technology often was used for soldering of brass. The purpose of this study is investigating soldering-ability and wettability of lead-free solder on lead-free free-cutting brass. Hence, we investigated the soldering ability of lead-free solders, Sn-5%Sb and Sn-3%Ag-0.5%Cu, for pure Cu and brass joints with nonuniform heating by hot plate.

• Periodical: Materials Science Forum (Volume 1016)
• Pages: 1448-1453
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1016.1448
• Online since: January 2021
• Authors: Hikaru Tajima*, Yuta Nakamura, Yasuyuki Miyazawa, Hidenobu Tameda
• Keywords: In Situ Observation, Pb-Free Copper, Pb-Free Solder, Soldering

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