Aircraft Alloys / 4620 VM

4620 Vac Melt is an aircraft quality nickel, molybdenum, manganese low alloy steel typically used for carburized parts that require high minimum core hardness and allow wide hardness range. This material is usually melted in an Electric Furnace, and then remelted via Consumable Electrode Vacuum Arc Remelting. This produces a much cleaner steel meeting the magnetic particle test requirements of AMS-2300. This alloy is able to be heat treated to high strength levels. Before heat treatment or carburization, welding is possible by conventional means. 4620 steel is easily machinable and is perfect for applications that demand carburized parts with outstanding toughness and core strength. This material is often used to produce shafts and gears in a wide variety of industries, such as aerospace and automotive. (UNS G46200)

Chemical Makeup

Element Min Max
Carbon, C 0.17 0.22
Manganese, Mn 0.45 0.65
Silicon, Si 0.15 0.35
Phosphorus, P - 0.025
Sulfur, S - 0.025
Chromium, Cr - 0.2
Molybdenum, Mo 0.2 0.3
Nickel, Ni 1.65 2
Copper, Cu - 0.35
Aluminum, Al 0.02 0.05
Vanadium, V 0.02 0.08
Columbium/Niobium, Nb 0.02 0.05

Common Applications

  • Aerospace Aerospace
  • Defense Defense
  • Industrial Industrial


  • High Core Hardness
  • Outstanding Toughness
  • Good Machinability

We stock 4620 VM to the following specifications:

  • AMS-2300
  • AMS-6294
  • ASTM-A-331
  • MIL-S-7493

Click on a cross-section to see the sizes we stock:

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