What Does Maraging Steel Mean?
Maraging steel is high-strength steel that possesses increased toughness. It is also refers to the aging of martensite, a hard microstructure commonly found in steels.
The term maraging is derived from the strengthening mechanism, which transforms the alloy to martensite with subsequent age hardening.
Maraging steels work well in electromechanical components where ultra-high strength is required, along with good dimensional stability during heat treatment. They are used particularly in aerospace and tooling applications.
Corrosionpedia Explains Maraging Steel
Maraging steels are carbon-free nickel-rich alloys which possesses superior strength and toughness without losing malleability. These steels are a special class of low-carbon ultra-high-strength steels which derive their strength not from carbon, but from precipitation of intermetallic compounds. The main alloying element is 15 to 25 wt.% nickel. Minor alloying elements are cobalt, molybdenum and titanium which are added to produce intermetallic precipitates.
Common, non-stainless grades of steel contain 17% to 19% nickel, 8% to 12% cobalt, 3% to 5% molybdenum and 0.2% to 1.6% titanium. Stainless grades rely on chromium not only to prevent corrosion, but to augment the hardenability of the alloy as their nickel content is substantially reduced. This is to ensure they can transform to martensite when heat treated, as high-chromium, high-nickel steels are generally austenitic, and unable to undergo such a transition.
The working characteristics of maraging steel, along with its strength, make this alloy a particularly useful one from a manufacturing perspective. Before maraging steel is aged or heat-treated, it can be cold-rolled to a significant extent without cracking and can also be nitrided or case-hardened. The alloy is also easy to machine and very stable when heat-treated, showing very little thermally-induced dimensional change.
Non-stainless varieties of maraging steels are moderately corrosion resistant and resist stress corrosion and hydrogen embrittlement. More corrosion protection can be gained by cadmium plating or phosphating.