The carbon content of quenched and tempered steels usually ranges between 0.2% and 0.6%. The grade ultimately chosen depends on the desired balance between strength and ductility (based on the cross-section of the component) required for the respective application. Relevant factors include the chemical composition of the material, its thermal treatment and the operating temperature of the finished component. Quenched and tempered steels are either soft annealed or quenched and tempered at the production site. After prehardening, this steel does not usually require further heat treatment after machining. Quenched and tempered steels are used for crankshafts, axles, shafts, connecting rods, bolts and screws.