Phosphor Bronze Wire: Cast Billet Extruded at 570-620 °C, then Cold Drawn without Annealing (Barthel, Lurgi, US 2,079,239)

Cast phosphor bronze holds a brittle tin-rich phase that made wire drawing a long round of drawing and annealing. Barthel found that extruding the casting at 570-620 °C kneads it into one soft, even phase, after which it draws straight down to wire. Result: phosphor bronze wire, drawn without intermediate annealing. Source: Barthel, US 2,079,239 (American Lurgi, 1937). His temperature is for about 8 % tin; our ingot has about 9 %, so the same range is ours. Not given: extrusion ratio, die sizes. Picture drawn by Youblob.