GB755084A - Manufacture of plain bearings - Google Patents

Abstract

Before casting tin-containing babbitt metal on to a bronze backing to make a composite bearing a barrier layer of a metal or alloy, such as nickel, cobalt or iron, of a character which prevents or substantially inhibits diffusion of tin from the babbitt metal into the bronze, and is capable of forming a bond with the babbitt metal and with the bronze, is applied to the appropriate surface of the backing. In an example a cylindrical bronze backing is electroplated internally with nickel, cobalt, or iron, the outside coated with a stop-off preparation to prevent tinning, dipped in or wiped with a zinc chloride solution, immersed in a tinning bath of tin or 70/30 lead-tin alloy at between 500 DEG -800 DEG F., removed therefrom and placed in a centrifugal casting machine, and tin-containing babbitt metal cast-on. In another example, a bronze backing shell is anodically etched, rinsed, dipped in an aqueous solution of hydrochloric acid 14 per cent and tartaric acid 5 per cent, nickel plated internally and babbitt metal cast into the shell between its inner surface and a carbon core. The bronze backing may be by percentages Cu 80, Sn 10, Pb 10 or Cu 84, Sn 5, Pb 9, Zn 2. Bronze of the following composition is also referred to as used for railway rolling stock axles, Cu 73, Sn 5-7, Pb 14-22 and Zn up to 3. The babbitt metal may have the following compositions: expressed as percentages (a) Sn 3, Sb 10, Ag 2,6 remainder Pb, (b) Cu 5,7, Sb 6,7, Pb 0,35, remainder Sn, or (c) Sn 5, Cu 0,5, Sb 10, remainder Pb. Babbitt metal comprising Sn 3-15, Sb 8-10, Cu up to 0,5, remainder Pb is also referred to.