Bearing metal alloys:
Bearing metals are alloys specially used for moulding forms, when casting bearing of rotating machine parts or bearing pillows. Two alloy compositions are used for these purposes. First ones are red and the others are white. Bearings can be rolling bearings, fluid bearings and needle-roller bearings. For rolling element bearings, highly abrasion resistant chrome steel with long fatigue life is used. Bearing pillows for high pressure and push are alloyed with copper, while those, which are suitable for low pressure and little friction, are produced with zinc or tin alloyed mouldings. The materials for bearings should be strongly abrasion resistant, chemically stabile, shock resistant and should resist repeated stress. Metals’ structure must be homogeneous, must hold size to be able to ensure silent long-term use. Metals for bearings must bear extreme stress, like under lack of lubrication when starting or malfunctioning of an engine, which can result in high friction and work on high temperature. It can also happen that the engine part heats up very well after negative temperature period and its metal components expand and it can not result disfunction. Bearings can work under extrem circumferences, regarding temperature and stress, and bearings work reliable in these cases due to the special alloyed materials.
Bearing pillow alloys: those low-strength materials, which can only be used for stress-resistant bearing pillows:
Bearing metals with lead base: In these metals, the soft basic metal is lead, the hard crystal structure is the compounds of alloying materials. They have low strength, are suitable for bearings (white metal), can bear smaller pressure and their abrasion is higher than the abrasion of tin-based bearings.
Bearing metals with tin base: Bearing metals with tin base or so called white metals. They have good slipping and run-in characteristics and are sensible to dynamic pressure.