Good mechanical and technological properties, quenching high, adding vanadium steel grain refinement, reducing overheating sensitivity, improves the strength and toughness, has high fatigue strength, yield ratio is relatively high, but the welding of poor, cold due to plastic deformation is low. It is a kind of higher spring, used as a larger cross section of the high load important spring and valve spring, spring piston, the safety valve spring who works at working temperature Below 300 ℃.