Good mechanical and technological properties, hardenability higher, adding vanadium steel grain refinement to reduce the thermal sensitivity, improved strength and toughness, high fatigue strength, yield a higher ratio, but the poor weldability , cold deformation plasticity. A higher spring, as a larger cross-section of the important spring of the high-load and operating temperature <300 ° C, valve springs, piston spring safety valve spring 
 ASTM6150 spring steel mechanical properties: tensile strength σb (MPa): ≥ 1274 (130) yield strength σs (MPa): ≥ 1127 (115) the elongation δ5 (%): ≥ 10 section shrinkage ψ (%): ≥ 40 Hardness: Hot ≤ 321HB; Cold Drawn + heat treatment ≤ 321HB Heat Treatment Specification: quenched 850 ° C ± 20 ° C, cold oil; tempering 500 ° C ± 50 ° C (special needs, ± 30 ° C). 
 Delivery status: the state of hot-rolled steel to heat treatment or no heat treatment delivery, cold drawn steel to heat treatment delivery 
 ASTM6150 spring steel chemical composition: 
 S ≤ 0.040 sulfur, phosphorus P ≤ 0.035, chromium Cr0.80 ~ 1.10, nickel of Ni ≤ 0.35, copper Cu ≤ 0.25, vanadium V0.10 ~ 0.20