UNS N08904 (904L) — Chemical Composition & Mechanical Properties
UNS N08904 (904L) is a super austenitic stainless steel grade for forgings (a182 f904l) (UNS N08904, EN / W.Nr 1.4539). This sheet summarises its chemical composition limits, minimum mechanical properties, heat treatment and typical service. Teshi Group manufactures flanges and fittings in this grade.
UNS N08904 (904L) at a glance
| Specification | UNS N08904 (904L) |
|---|---|
| Material family | Super austenitic stainless steel |
| Product form | Forgings (A182 F904L) |
| UNS number | N08904 |
| EN / W.Nr equivalent | 1.4539 |
| Also known as | 904L |
| PREN (min values) | 32.2 |
| Document | TG-MG-046 · Rev. 1 · October 2026 |
Typical service
Sulphuric / phosphoric acid and chloride service
Heat treatment
Solution annealed 1050–1150 °C, liquid quench
Chemical composition of UNS N08904 (904L) (weight %)
Single values are maximums unless shown as a range or “min”.
Mechanical properties
| Tensile strength, min | 490 MPa |
|---|---|
| Yield strength, min | 215 MPa |
| Elongation, min | 35 % |
| Hardness | Not specified |
About super austenitic stainless steel
Super austenitic stainless steels are high-alloy austenitic grades with much more nickel, molybdenum and nitrogen than 316L. That raises the pitting resistance equivalent number (PREN) from about 24 to 35–45, giving resistance to seawater, chlorides and strong acids where 316L would pit or crack.
Reference information compiled from the published standard for convenience. It does not replace the current edition of the governing standard, which takes precedence. Verify critical dimensions and properties before design, purchase or fabrication. Teshi Engineers & Sales Promoters (P) Ltd accepts no liability for errors or omissions.
International equivalents of UNS N08904 (904L)
All equivalents| Standard system | Nearest equivalent grade |
|---|---|
| USA — specification | UNS N08904 (904L) |
| USA — UNS | N08904 |
| Europe — EN designation | X1NiCrMoCu25-20-5 |
| Europe — W.Nr | 1.4539 |
| Japan — JIS | SUS890L |
| China — GB / NB | S39042 (015Cr21Ni26Mo5Cu2) |
| China — old GB designation | 00Cr20Ni25Mo4.5Cu |
| UK — BS (withdrawn) | 904S13 |
Equivalents are the nearest commonly cited grades. Chemistry, mechanical properties and testing differ between standards — compare them before substituting one for another.
Same alloy in other product forms
| Product form | Specification / grade |
|---|---|
| Flanges & forged fittings | ASTM A182 F904L / B649 |
| Butt-weld fittings | ASTM A403 WP904L / B366 WPN08904 |
| Pipe | ASTM A312 / B677 N08904 |
| Plate | ASTM A240 / B625 N08904 |
| Bar | ASTM B649 N08904 |
Other super austenitic stainless steel grades
Super austenitic stainless steel overviewStandards for UNS N08904 (904L)
All material standardsFAQ
UNS N08904 (904L): common questions
What is the minimum yield strength of UNS N08904 (904L)?
215 MPa, with a minimum tensile strength of 490 MPa.
What is the carbon content of UNS N08904 (904L)?
0.020 max %.
What is the PREN of UNS N08904 (904L)?
About 32, calculated as Cr + 3.3Mo + 16N using the specification minimum values. Typical heats are a little higher.
What is the UNS number and EN equivalent of UNS N08904 (904L)?
UNS N08904; the nearest European designation is W.Nr 1.4539. Equivalents are close but not identical — check the specification if substituting.
How is UNS N08904 (904L) heat treated?
Solution annealed 1050–1150 °C, liquid quench.
What is the Chinese (GB) equivalent of UNS N08904 (904L)?
The nearest Chinese equivalent is S39042 (015Cr21Ni26Mo5Cu2), formerly 00Cr20Ni25Mo4.5Cu. Equivalents are close but not identical — compare chemistry and properties before substituting.
What is the JIS equivalent of UNS N08904 (904L)?
The nearest Japanese (JIS) equivalent is SUS890L.
Does Teshi Group supply UNS N08904 (904L)?
Teshi Group manufactures flanges and fittings in this grade. Send your size, rating and quantity to info@teshigroup.com for a quotation with EN 10204 3.1 certificates.
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