Alloy N40 - UNS S21900/S21904

Alloy N40, UNS S21900/S21904, is commonly associated with ASTM A276 - ASTM A479 - AMS 5595 - AMS 5656.
Alloy N40 is commonly known as Nitronic® 40, 21-6-9, XM-10 and XM-11, and our HPA N40. Alloy N40 is a Nitrogen strengthened, high Manganese Stainless Steel alloy. While designated as UNS S21900, only the lower Carbon version, UNS S21904, is commercially available.
Mechanical properties here.


Ni Cr Mn C Si N S
Max % 7.50 21.50 10.0 0.08 1.00 0.40 0.030
Min % 5.50 19.00 8.0 0.15

Typical Inventory

Round Bar, Forge, Billet

Product Description

N40 is a nitrogen-strengthened, high-manganese stainless steel with high strength and excellent resistance to corrosion at high temperatures. N40, also called Nitronic 40®, can be fabricated and is readily weldable. N40 has been used for chemical processing, pollution control equipment and various aircraft engine components.


  • Food and chemical processing.
  • Aircraft components.
  • Polution control equipement.

Mechanical Properties

The typical properties listed can usually be provided in rounds, sheet, strip, plate, & custom forgings. We have the equipment to produce small quantities in special sizes to meet our customers’ specific needs.

Ultimate Tensile ksi (MPa) Yield Strength ksi (MPa) Elong. % in 2 in. Hardness (Rockwell B)
Min 95 (655) 48 (330) 35
Max 100

Common Specifications

Please, note that the specs listed are for reference and are not comprehensive nor indicative of the actual specifications listed on the Material Test Report (MTR). If you have a special spec requirement, then please reach out to our sales department at 1-800-472-5569.

AMS 5595, AMS 5656, ASME SA 240, ASTM A 240, ASTM A 276, ASTM A 479, ASTM A 666

Electralloy's brochure on Nitronic 40

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