The roller bearing mounts are divided into two types: one is a pressed bearing seat, and the other is a cast iron (gray iron) bearing seat. The pressed bearing seats are mostly welded to steel pipes, while the cast iron bearing seats are all extruded with steel pipes. The features of the pressed bearing seats are good sealing and strong overall load-bearing capacity. The major characteristic of the cast iron bearing seats is high concentricity, but their load-bearing capacity is lower than that of the pressed bearing seats.