Zinc - aluminum alloys are obtaining wide acceptance in journal bearings for high-load, low-speed power transmission applications. These alloys, most notably ZA-12 and ZA-27, are capable of replacing traditional bronze bearings, often at lower cost.
In this paper the contents of a new zinc - aluminum (ZA) alloy design manual for continuous rotation bearings are described. Those sections and design topics discussed in detail include general metallurgy of ZA alloys, journal selection and clearances, bearing wall thickness, lubrication, conformability and embeddability, design charts and corrosion aspects. A direct comparison is made between ZA alloys and C93200 (SAE 660) Pb-Sn bronze. This is achieved by virtue of the carefully controlled side by side testing of ZA and bronze journal bearings on which the design aspects of the manual are based. In addition, reference to aluminum bronze and various zinc alloys in the sand cast, pressure die cast, permanent mould, continuously cast and centrifugally cast conditions is provided in terms of wear rate measurements from Block on Ring testing.