51CrV4 (1.8159) spring steel good mechanical properties and process performance, high hardenability, adding vanadium to steel the grain refinement, reduce heat sensitivity, increased strength and toughness, high fatigue strength, yield ratio is high, but poor welding, cold plastic deformation due to the low.

51CrV4 is a relatively high spring, as a large section of the important spring and high-load operating temperature <300 ℃ of the valve spring, piston spring, valve spring.

Chemical composition
Carbon C: 0.47 ~ 0.55


Si Si: ≤ 0.40


Manganese Mn: 0.70 ~ 1.10


Sulfur S: ≤ 0.030


Phosphorus P: ≤ 0.030


Chromium Cr: 0.90 ~ 1.20


Ni-Ni: ≤ 0.35


Copper Cu: ≤ 0.25


Vanadium V: 0.10 ~ 0.25

Mechanical properties
Tensile strength σb (MPa): ≥ 1274 (130)


Yield strength σs (MPa): ≥ 1127 (115)


Elongation δ5 (%): ≥ 10


Reduction of area ψ (%): ≥ 40


Hardness: hot, ≤ 321HB; cold-drawn + heat treatment, ≤ 321HB

Standard heat treatment and microstructure
Standard heat treatment: quenching 850 ℃ ± 20 ℃, oil cooling; tempering 500 ℃ ± 50 ℃ (special needs, ± 30 ℃).


● Delivery status: hot-rolled steel to heat treatment or heat treatment delivery, cold-drawn steel with heat treatment delivery.