The roller bearing brackets are divided into two types: one is a bushing bracket, and the other is a cast iron (gray iron) bearing bracket. The bushing brackets are mostly welded to steel pipes, while the cast iron bearing brackets are all extruded onto steel pipes. The characteristics of the bushing brackets are good sealing and strong overall load-bearing capacity. The main feature of the cast iron bearing brackets is high concentricity, but their load-bearing capacity is lower than that of the bushing brackets.