Maraging 300 - Super Alloy - Fry Steel

Super Alloy / MARAGING 300

Maraging 300 alloy steel is a very high strength iron base, molybdenum, cobalt and nickel alloy. This product is a premium aircraft-quality steel produced by multiple melting cycles using a consumable electrode vacuum remelt (VAR) practice in the remelt cycle. Maraging 300 is offered in the annealed condition and can be aged to a nearly 300 ksi tensile (2068 MPa) with similar yield results, a nominal 11% elongation, and an above-average level of toughness. The alloy retains its strength up to 450C and good notch impact is maintained down to minus 50C and below. This material may be nitride and is readily weldable. Maraging 300 is very tough and relatively soft making it easily machined for critical components in aerospace, structural and tooling applications. (UNS K93120)

Chemical Makeup of Maraging 300 Alloy Steel

Element Min Max
Carbon, C -- 0.03
Manganese, Mg -- 0.1
Silicon, Si -- 0.1
Phosphorus, P -- 0.01
Sulfur, S -- 0.01
Nickel, Ni 18 19
Cobalt, Co 8.5 9.5
Molybdenum, Mo 4.6 5.2
Titanium, Ti 0.5 0.8
Aluminum, Al 0.05 0.15
Chromium, Cr -- 0.5
Copper, Cu -- 0.5

Common Applications of 300 Alloy Steel

  • Aerospace Aerospace
  • Industrial Industrial


  • High Strength
  • High Toughness
  • Good Ductility
  • Good Weldabiliy

We stock MARAGING 300 to the following specifications:

  • AMS-6514
  • HMS-6-1404 T-2 CL. 1 (INQUIRE)
  • LBO-160-164 (INQUIRE)
  • MBO-160-006 EXC. SONIC (INQUIRE)
  • MIL-S-46850 TYPE 4 EXC. PARA.3.5.3

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

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