Significance of Alloying Element Levels in Realizing the Specified Tensile Properties in 18 Wt % Nickel Maraging Steel

Muktinutalapati Nageswara Rao, Krishnan Sivasubramanian

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DOI: 10.4236/msa.2011.28150                

Abstract

Among the various grades of commercially available 18 wt. % nickel maraging steels, the one with nominal 0.2% proof strength in the range 1700-1750 MPa is the most commonly used and is distinguished by an excellent combination of high strength and high fracture toughness. The main alloying elements are nickel, cobalt, molybdenum and titanium. The first three of these are present at relatively high concentrations in the chemical composition. The high cost of these metals leads to a high cost of production and this becomes a deterrent to extensive use of the steel. In the present study, an attempt was made to produce the steel by pegging the levels of these alloying elements in the lower half of the specified range. The objective was to save on the raw material cost, while still conforming to the specification. The steel so produced could not, however, attain the specified tensile properties after final heat treatment. The observed behavior is explained based on the role played by the different alloying elements in driving the precipitation hardening reaction.

Keywords

18 % Ni Maraging Steel, Chemical Composition, Alloying Elements, Age Hardening, Tensile Properties

Conflicts of Interest

The authors declare no conflicts of interest.

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