Nitronic

Stainless steel alloy trade name

For the nitronic acid functional group, see Nitronate.

Nitronic is the trade name for a collection of nitrogen-strengthened stainless steel alloys. They are austenitic stainless steels.

## History

[edit]

Nitronic alloys were developed by Armco Steel. The first of these alloys, Nitronic 40, was introduced in 1961.[1] Since 2022, the trademark has been owned by Cleveland-Cliffs Steel Corp., successor to AK Steel.[2] Electralloy is the licensed producer in North America for a wide range of Nitronic products.[3]

The Nitronic name is due to the addition of nitrogen to the alloy, which enhances the strength internally rather than being nitrided on the surface, as some steel are treated. The nitrogen is homogeneous throughout the material. Nitronic materials have about twice the yield strength of 304L and 316L.[4]

## Uses

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Nitronic 30 is used to lighten transportation vehicles.[5] Buses and railcars benefit from the high strength-to-weight ratio for weight savings. Nitronic 40 is used at cryogenic temperatures.[6] and in the aerospace industry as hydraulic tubing.[1] Nitronic 50 is used in marine environments, including boat shafting and solid rod rigging.[7] Nitronic 60 and a similar alloy Gall-Tough have high resistance to galling, a form of wear caused by adhesion between sliding surfaces, and metal-to-metal wear.[8][9]

## Composition

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Nitronic alloys have widely varying compositions, but all are predominantly iron, chromium, manganese and nitrogen.

NITRONIC  | Element (% by mass)

|

Fe | Cr | Ni | Mo | Nb | Mn | Si | C | S | P | V | N
30 UNS S20400

[10]

| Bal  | 15.0–17.0  | 1.5–3.0  |  |  | 7.0–9.0  | 1 max  | 0.03 max  | 0.03 max  | 0.04 max  |  | 0.15–0.3
32 UNS S24100

[11]

| Bal  | 16.5–19.0  | 0.5–2.5  |  |  | 11.–14.0  | 1 max  | 0.15 max  |  | 0.045 max  |  | 0.2–0.45
33 UNS S24000

[12]

| Bal  | 17.0–19.0  | 2.3–3.7  |  |  | 11.5–14.5  | 0.75 max  | 0.08 max  | 0.01 max  | 0.06 max  |  | 0.–0.4
40 UNS S21900

[13]

| Bal  | 19–21.5  | 5.5–7.5  |  |  | 8.0–10.0  | 1 max  | 0.04 max  | 0.01 max  | 0.04 max  |  | 0.2–0.4
50 UNS S20910

[14]

| Bal  | 20.5–23.5  | 11.5–13.5  | 1.5–3.0  | 0.01–0.03  | 4.0–6.0  | 0.2–0.6  | 0.03 max  | 0.01 max  | 0.04 max  | 0.1–0.03  | 0.2–0.4
60 UNS S21800

[15]

| Bal  | 16–17  | 8.0–8.5  | 0.75 max  | 0.10 max  | 7.5–8.5  | 3.7–4.2  | 0.06–0.08  | 0.03 max  | 0.040 max  | 0.2 max  | 0.1–0.18

## References

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1. ^ a b Harold M. Cobb (2010). The History of Stainless Steel. ASM International. p. 305\. ISBN 9781615030118. Retrieved March 19, 2017.
2. ^ United States Patent and Trademark Office (March 23, 2022). "NITRONIC Serial# 73219917". p. 1. Retrieved January 13, 2023.
3. ^ "When your application is critical, when there is no room for error, your choice is Electralloy". Electralloy. 2017. "Electralloy is North America's exclusive licensed producer of all NITRONIC® bar, billet, coil rod, master alloy pigs and ingot products as well as NITRONIC® weld wire and weld consumables."
4. ^ C. G. Fountzoulas; E. M. Klier; J. E. Catalano (2016). Dan Casem; Leslie Lamberson; Jamie Kimberley (eds.). Dynamic Behavior of Materials, Volume 1: Dynamic Characterization of Nitronic 30, 40 and 50 Series Stainless Steels. Springer. p. 22\. ISBN 978-3319411323. Retrieved March 19, 2017.
5. ^ Bruce Emmons (June 27, 2016). "Ultralight Electric Bus". p. 1. Retrieved March 19, 2017.
6. ^ Di Giovanni, Mario (1982). Flat and Corrugated Diaphragm Design Handbook. CRC Press. p. 42\. ISBN 9780824712815.
7. ^ Dan Spurr (January–April 1982). "Cruising World". p. 68. Retrieved March 19, 2017. `{{cite magazine}}`: Cite magazine requires `|magazine=` (help)
8. ^ Davis, Joseph R. (2000). Alloy Digest Sourcebook: Stainless Steels. ASM International. p. 3\. ISBN 9780871706492.
9. ^ viking (January 20, 2023). "Advantages of Using Nitronic 60 fasteners in Industrial Applications". Zeon Fasteners LLP. Retrieved August 18, 2023.
10. ^ AK Steel. "Nitronic 30 Stainless Steel" (PDF). Retrieved March 19, 2017.
11. ^ Electralloy. "Nitronic 32 Stainless Steel" (PDF). Retrieved March 19, 2017.
12. ^ Electralloy. "Nitronic 33 Stainless Steel" (PDF). Retrieved March 19, 2017.
13. ^ Electralloy. "Nitronic 40 Stainless Steel" (PDF). Retrieved March 19, 2017.
14. ^ Electralloy. "Nitronic 50 Stainless Steel" (PDF). Retrieved March 19, 2017.
15. ^ Electralloy. "Nitronic 60 Stainless Steel" (PDF). Retrieved March 19, 2017.