1) Sliding contact surfaces: Steel vs. bronze.
2) Materials: Outer race is made of carbon steel, inner race is made of high chrome bearing steel, medium race is bronze.
3)
Heat treatment: Without heat treatment on outer race and bronze race.
Inner race is quenched (hardened), and surface plated with chrome.
4)
Features of structure: With oil groove or oil hole. Outer race formed
by extrusion. With a bronze race between outer race and inner race.
5) Properties: Self-lubricated, low friction, good wearability, self-alignment.
