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6009 |
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Thursday, May 23, 2019, Saal Brüssel 10:40 AM Development of brazing metals |
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Estimation of Pb-free brass soldering-ability using in situ observation method |
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Hikaru Tajima* / Tokai University, Japan Hiroki Okada / Tokai University, Japan Yasuyuki Miyazawa/ Tokai University, Japan Hidenobu Tameda/ Kitz Metal Works Corporation, Japan |
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Conventionally, brass has viscosity more than other metals, so there is a concern about its poor machinability. Therefore, improvement of machinability was attempted by adding lead to brass. It is a kind of brass called free cutting brass, typified by JIS C3771. This free-cutting brass is used for piping components and machine parts. However, Drinking Water Quality Standards Law have been amended and it restricts lead content in the free cutting brass. Reason for, due to a concern about elution of the lead into drinking water. 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. |