The purpose of this paper is to describe the advantages and validity of substituting the high-performance zinc casting alloys, ZA-12 and ZA-27, for bronze in selected low-speed, medium temperature bearing and bushing applications.
Because the cost per unit volume of ZA-12 and ZA-27 is less than half that of SAB 660 bronze, these zinc alloys will provide major cost savings in the OEM and replacement markets whenever they equal or exceed bronze performance on the selected applications.
For the foundry, these alloys offer significant advantages over bronze: lower energy requirements, no dependency on tin (a strategic material), and no pollution problems common to the leaded bearing bronzes.
With a natural lubricity and hardnesses exceeding those of 660 bronze, the the properties of ZA-12 and ZA-27 alloys indicate good bearing potential. This has been confirmed by laboratory tests conducted by the Battelle Institute under the auspices of ILZRO and in field tests conducted by Kidd Creek Mines, Ltd. (formerly Texasgulf Metals Company).
History, property data, laboratory data, and field experience will be presented, along with guidelines for applying the zinc alloys to bearing applications.