Grade: spring steel 735A50 Features and Scope: good mechanical properties and process performance, high hardenability, adding vanadium steel, grain refining, reducing heat sensitivity, increased strength and toughness, high fatigue strength , the yield ratio is high, but the poor weldability, cold plastic deformation due to low. Is a relatively high spring, as large sections of the important spring and high load operating temperature <300 ℃ valve springs, piston spring, safety valve spring Chemical Composition: Carbon C: 0.46 ~ 0.54 Si Si: 0.17 ~ 0.37 Manganese Mn : 0.50 ~ 0.80 Sulfur S: ≤ 0.030 Phosphorus P: ≤ 0.030 Chromium Cr: 0.80 ~ 1.10 Ni-Ni: ≤ 0.35 Copper Cu: ≤ 0.25 Vanadium V: 0.10 ~ 0.20 Mechanical Properties: Tensile strength σb (MPa): ≥ 1274 ( 130) yield strength σs (MPa): ≥ 1127 (115) Elongation δ5 (%): ≥ 10 Reduction of area ψ (%): ≥ 40