General Discussion—Historical Note on the Slow Strain Testing of Solder
SourceThis is a historical note describing an early experience of Aaron Hachter, Ross Miller, and the writer with slow strain-rate stress corrosion testing. In 1945 there was some concern about the possibility of stress-related corrosion effects on the soldered joints in automobile radiators when sodium nitrite was used as a corrosion inhibitor in the radiator coolant. The accepted method of determining stress corrosion cracking (SCC) susceptibility in those days was to make tests using U-bend specimens. Obviously, this technique was not compatible with the mechanical properties of solder. Therefore, a test method was devised; this method was called a creep corrosion test. The specimen was a 50.8 mm long by 3.2 mm (2 by ⅛ in.) diameter rod of 50-50 solder (50Sn, 50Pb) with brass end pieces. The specimen was loaded in tension by a 0.34 kg (0.75 lb) steel weight. Figure 1 shows the simple apparatus that was used.