Alloy Grade UNS: CK3MCuN – Corrosion Resistant

  • Overview

    CK3MCuN is a high-performance austenitic stainless-steel alloy specifically formulated for exceptional corrosion resistance, even in challenging chloride-rich environments. With a composition of up to 20.5% chromium and 19.5% nickel, this alloy exhibits remarkable resistance to various forms of corrosion, including pitting and crevice corrosion, particularly in seawater and other aggressive media. Its low carbon content of 0.025% ensures a fully austenitic microstructure, contributing to its excellent corrosion resistance and weldability. This combination of properties makes CK3MCuN a valuable choice for applications where superior corrosion resistance in harsh environments is paramount.

  • Typical Uses

    Chemical and food processing equipment, desalination equipment, impellers, process piping exposed to flue gas.

  • MetalTek Grade

    254 SMO®

  • Poured At:

    Carondelet Division, Sandusky International Division, Wisconsin Centrifugal Division, Wisconsin Investcast Division

* Produced under license of Avesta.

Similar Specifications

Wrought UNS: S31254

Wrought Grade: 254 SMO®

Cast ASTM: A351, A743, A744

Typical Chemical Composition (% by wt.)

Aluminum: n/a

Carbon: 0.025

Chromium: 19.5-20.5

Manganese: 1.2

Iron: n/a

Copper: 0.5-1.0

Nickel: 17.5-19.5

Lead: n/a

Tin: n/a

Silicon: 1

Zinc: n/a

Other: Mo 6-7; N 0.18-0.24

Minimum Mechanical Properties

Tensile, ksi

0

Tensile, MPa

0

Calculated PREn (Minimum)

0

Yield, ksi

0

Yield, MPa

0

Elongation

0%

Heat Treatment: Solution Anneal

Frequently Asked Questions

Super austenitic steel is a high-alloy stainless steel with enhanced levels of chromium, molybdenum, and nitrogen, providing superior resistance to chloride-induced corrosion.

Used in desalination plants, offshore platforms, chemical processing, marine equipment, and pulp & paper industries where high chloride or acidic environments are present.

Super austenitic steels offer higher molybdenum and nitrogen levels than standard austenitic steels, improving their resistance to pitting, crevice, and stress corrosion.

Benefits include exceptional resistance to aggressive environments, high strength, extended life in chloride-rich applications, and suitability for welding and fabrication.

Its high levels of molybdenum, chromium, and nitrogen promote the formation of a passive oxide layer that protects against localized and general corrosion.

Grades such as 254SMO and AL-6XN are considered super austenitic stainless steels, offering premium corrosion resistance in extreme environments.

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Stainless steels owe their ability to resist corrosion primarily to the presence of a passive film on their surface. Chromium is chiefly responsible for formation of the passive film. Iron ceases to rust at approximately 12% chromium content and resistance to oxidizing corrosives increases rapidly with chromium content up to approximately 20%.
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