1) Sliding contact surfaces: Steel vs. Steel.
2) Materials: Outer race is made of carbon steel, inner race is made of high chrome bearing steel.
3) Heat treatment: Without heat treatment on outer race. Inner race is quenched (hardened), and surface plated with chrome.
4) Features of structure: With oil grooves and oil holes. Outer race formed by extrusion.
5) Properties: Good wearability, self-alignment.
