Aluminum alloy bearing

DETAILED DESCRIPTION The present invention concerns an aluminum alloy for shaft bearings wherein the alloy contains approximately 8% tin (Sn), 2.
5% silicon (Si), 2% lead (Pb), 0.
8% copper (Cu) and 0.
2% chromium (Cr) on a weight percentage basis, balance aluminum.
The improved aluminum alloy is specifically designed to take advantage of the quench casting and roll bonding processing technologies.
The improved aluminum alloy is designed to provide a desired grain structure when it is quench cast, and to have a high strength adherence to the steel backing strip after going through the roll bonding operation.
Each alloying element is carefully balanced with each other alloying element to achieve a bearing alloy which optimizes seizure resistance, fatigue resistance, machinability and resistance to cracking during quench casting.
The new alloy is cast by a rapid solidification process, resulting in a fine distribution of components in the microstructure and contains a relatively low amount of soft phase (tin+lead), resulting in higher fatigue strength than would otherwise be expected.
Despite the lower amount of soft phase, careful control of microstructure and careful selection of the other ingredients has resulted in superior seizure resistance.
The aluminum alloy strip may be bonded directly to the steel back, obviating the need for an intermediary aluminum bonding layer of pure aluminum, nickel, silver or copper which have been thought to reduce the fatigue resistance of the lining and adds to the cost of the bimetal strip.
The tin and lead are present in the elemental state.
They are soft phases that contribute to the embeddability of the alloy and give the alloy good anti-seizure properties.
In an emergency situation, localized heating from high friction can cause the soft phase to melt, providing lubricity to the bearing surface and thereby deterring catastrophic failure.
The silicon has been found to greatly improve the wear resistance of the alloy.
Silicon also makes a significant contribution to the anti-seizure properties of the alloy