The Influence of Bismuth on Brass and Its Relation to Fire‐cracks.

Abstract

It is a tradition i n the brass industry that bismuth is an injurious element in brass, even more deleterious than antimony ; but such a belief has lacked verification. The occasional presence of bismuth in commercial copper (although less frequent than was formerly 'supposed) led the author to investigate this tradition.The following experiments were conducted in the same manner as those described in a previous paper on " The Influence of Antimony on Brass," to which the reader is referred for details. The purest Lake Superior copper was used, and after it had been melted the bismuth was introduced as an alloy of copper and bismuth. Zinc in the form of pure refined metal was next added, and the mixture wasstirred and poured into an iron mould Q X 2Q x 24 inches. All rolling was performed cold. ~ For reasons previously mentioned, a base alloy was used, consisting of copper, 60 per cent., and zinc, 40 per cent. ExpenNzent LVO. r. 59.50 ; zinc, 40 ; bismuth, 0.50 per cent. Melted 5.5 pounds of copper, added 0.5 pound of an alloy of copper, go, and bismuth, 1 0 per cent., and then 4 pounds of zinc. Rolled from 0.595 to 0.472 inch, a reduction of 20 per cent. Cracked badly on one edge, but otherwise the surface appeared unchanged. Annealed, and the plate fire-cracked on both sides, While many of the cracks were merely superficial, others penetrated the metal so deeply that further rolling became impossible. While this alloy is cold-short, it is less so than the corresponding antimony alloy. The fracture was finely crystalline.