Maraging Steel

//Maraging Steel
Maraging Steel2018-09-21T10:58:03+00:00

Maraging Steel

Maraging steels (a portmanteau of “martensitic” and “aging”) are steels (iron alloys) that are known for possessing superior strength and toughness without losing malleability, although they cannot hold a good cutting edge. Aging refers to the extended heat-treatment process. These steels are a special class of low-carbon ultra-high-strength steels that derive their strength not from carbon, but from precipitation of intermetallic compounds. The principal alloying element is 15 to 25 wt.% nickel.[1] Secondary alloying elements, which include cobalt, molybdenum, and titanium, are added to produce intermetallic precipitates.[1] Original development (by Bieber of Inco in the late 1950s) was carried out on 20 and 25 wt.% Ni steels to which small additions of Al, Ti, and Nb were made; a rise in the price of cobalt in the late 1970s led to the development of cobalt-free maraging steels.[2]

The common, non-stainless grades contain 17–19 wt.% nickel, 8–12 wt.% cobalt, 3–5 wt.% molybdenum, and 0.2–1.6 wt.% titanium. Addition of chromium produces stainless grades resistant to corrosion. This also indirectly increases hardenability as they require less nickel: high-chromium, high-nickel steels are generally austenitic and unable to transform to martensite when heat treated, while lower-nickel steels can transform to martensite. Alternative variants of Ni-reduced maraging steels are based on alloys of Fe and Mn plus minor additions of Al, Ni, and Ti where compositions between Fe-9wt.% Mn to Fe-15wt.% Mn have been used.[3] The Mn has a similar effect as Ni, i.e. it stabilizes the austenite phase. Hence, depending on their Mn content, Fe-Mn maraging steels can be fully martensitic after quenching them from the high temperature austenite phase or they can contain retained austenite.[4] The latter effect enables the design of maraging-TRIP steels where TRIP stands for Transformation-Induced-Plasticity.

Applications

The maraging alloy 250 has a wide range of application including

  • Rocket motor casings.
  • Light aircraft landing gear.
  • Power shafts.
  • Low temperature tooling.

In Forms Of

Pipes & Tubes

Round Bars

Sheets Plates Coils

Forgings

Pipe Fittings

Flanges

Fastners

Flat Bars

Filler Rods