It is kind of medium carbon high quality steel with high strength, uaually used in normalizing state, due to the poor hardenability, use the modulation processing when the high performance requirements. moderate cold plastic deformation, better annealing and normalizing cutting machinability than modulation. used for the manufacture of parts with high strength requirements, such as Gear, shaft, piston pin and other mechanical parts with less stress, forging, stamping parts and bolts, nuts, pipe connection.