Is 50CrV4 steel and 51CrV4 steel the same material

50CrV4 steel and 51CrV4 steel are produced by different European standards, and the materials are basically the same. The main difference between 50CrV4 steel and 51CrV4 steel is the carbon content:
Carbon content of 50CrV4 steel: 0.46-0.54
Carbon content of 51CrV4 steel: 0.47-0.55

50CrV4 steel belongs to alloy spring steel. 50CrV4 steel is German standard steel grade, which corresponds to 50CrVA in China.

51CrV4 steel is a kind of higher-level spring steel. 51CrV4 steel has good mechanical and technological properties, high hardenability, high fatigue strength and high yield ratio. 51CrV4 steel is used as the important spring of high load with large cross-section and valve spring, piston spring and safety valve spring with working temperature < 300 ℃.

The main alloy steel grades of BBN steel are 38Cr2, 41CrS4, 50CrMo4, 51CrV4, 46Cr2, 25CrMo4, 30CrNiMo8, 20MnB5, 34Cr4, 25CrMoS4, 34CrNiMo6, 30MnB5, 34CrS4, 34CrMo4, 35NiCr6, 38MnB5, 37Cr4, 34CrMoS4, 36NiCrMo16, 27MnCrB5-2, 37CrS4, 42CrMo4, 39NiCrMo3, 33MnCrB5-2, 41Cr4, 42CrMoS4, 30NiCrMo16-6, 39MnCrB6-2, 20Mn2, 20MnVB, 12CrMoV, 20CrNi, 30Mn2, 40MnVB, 35CrMoV, 40CrNi, 35Mn2, 20MnTiB, 12Cr1MoV, 45CrNi, 40Mn2, 25MnTiBRE, 25Cr2MoVA, 50CrNi, 45Mn2, 15Cr, 25Cr2Mo1VA, 12CrNi2, 50Mn2, 15CrA, 38CrMoAl, 12CrNi3, 20MnV, 20Cr, 40CrV, 20CrNi3, 27SiMn, 30Cr, 50CrVA, 30CrNi3, 35SiMn, 35Cr, 15CrMn, 37CrNi3, 42SiMn, 40Cr, 20CrMn, 12Cr2Ni4, 20SiMn2MoV, 45Cr, 40CrMn, 20Cr2Ni4, 25SiMn2MoV, 50Cr, 20CrMnSi, 20CrNiMo, 37SiMn2MoV, 38CrSi, 25CrMnSi, 40CrNiMoA, 40B, 12CrMo, 30CrMnSi, 18CrNiMnMoA, 45B, 15CrMo, 30CrMnSiA, 45CrNiMoVA, 50B, 20CrMo, 35CrMnSiA, 18Cr2Ni4WA, 40MnB, 30CrMo, 20CrMnMo, 25Cr2Ni4WA, 45MnB, 30CrMoA, 40CrMnMo , 20MnMoB, 35CrMo, 20CrMnTi , 15MnVB, 42CrMo, 30CrMnTi, etc.