Stainless steels for extremely corrosive environments
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Ultra range products are designed for applications in extremely corrosive environments with a Pitting Resistance Equivalent (PRE) value of more than 27. This range gives you improved wet-corrosion capabilities and includes our key products Ultra 904L and Ultra 254 SMO as well as several alternatives for specific applications. The Ultra range is the best choice when you have experienced that grades like Core 304L/4307 or Supra 316L/4404 are not sufficient for the wet-corrosion challenges of your application. If you are unsure about which product is right for your application, you can rely on our experts to help you. We have long experience creating, producing and supplying stainless steels, combined with data from decades of our own corrosion tests. We invented some of the products in this range and have unrivalled experience in developing and producing wet-corrosion resistant alloys for aggressive conditions characterized by high levels of chlorides, high temperatures and low pH – or a combination of these factors.
Many of our products have been developed for specific customer needs, and we see innovation as a continuous process. Our Ultra range products are readily available around the globe and are delivered from mills that have long traditions of focusing on the customer and the end user of our products.
Our Ultra 904L is a high-nickel and petrochemical industry equipment such as pipes, heat exchangers, tanks, and reactor vessels
Ultra 254 SMO is for applications requiring resistance to chlorinated seawater, flue gas cleaning, maritime exhaust gas cleaning as well as bleaching equipment in the pulp and paper industry and flanges and valves.
A high-nickel and molybdenum austenitic stainless steel with very high corrosion resistance. Ultra 904L was originally developed for handling sulfuric acid at ambient temperatures, and is now used in a broad range of chemical industry applications.
EN 1.4539
ASTM type 904L
ASTM UNS NO8904
Microstructure Austenitic
Typical applications
Product forms
Datasheet
Typical chemical composition, % by mass
C 0.01
Cr 19.8
Ni 24.2
Mo 4.3
N -
Others 1.4Cu
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A molybdenum-alloyed austenitic stainless steel with higher corrosion resistance than Supra 316L/4404 – mainly used in the USA and Asia.
EN 1.4438
ASTM type
317L
ASTM UNS S31703
Microstructure Austenitic
Typical applications
Product forms
Data sheet
Typical chemical composition, % by mass
C 0.02
Cr 18.2
Ni 13.7
Mo 3.1
N -
Others -
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A molybdenum and nitrogen-alloyed austenitic stainless steel with significantly higher corrosion resistance than Supra 316L/4404. Also known as 317LMN.
EN 1.4439
ASTM type 317LMN
ASTM UNS S31726
Microstructure Austenitic
Typical applications
Product forms
Datasheet
Typical chemical composition, % by mass
C 0.02
Cr 17.3
Ni 13.7
Mo 4.1
N 0.14
Others -
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Ultra 725LN is a type 310 material (high chrome and high nickel) that has been developed and optimized specifically for urea production, which demand extremely high corrosion resistance. It has similar general pitting resistance to Ultra 904L.
EN 1.4466
ASTM type -
ASTM UNS S31050
Microstructure Austenitic
Typical applications
Product forms
Datasheet
Typical chemical composition, % by mass
C 0.01
Cr 25.0
Ni 22.3
Mo 2.1
N 0.12
Others -
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A 6% molybdenum, high-nickel and nitrogen-alloyed austenitic product with extremely high resistance to both uniform and localized corrosion.
EN 1.4529
ASTM type -
ASTM UNS N08926/N08367
Microstructure Austenitic
Typical applications
Product forms
Datasheet
Typical chemical composition, % by mass
C 0.01
Cr 20.5
Ni 24.8
Mo 6.5
N 0.20
Others Cu
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A 4.5% molybdenum, very high nitrogen alloyed austenitic stainless steel with excellent corrosion resistance and high mechanical strength.
EN 1.4565
ASTM type -
ASTM UNS S34565
Microstructure Austenitic
Typical applications
Product forms
Data sheet
Typical chemical composition, % by mass
C 0.02
Cr 24.0
Ni 17.0
Mo 4.5
N 0.45
Others 5.5Mn
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The most corrosion-resistant stainless steel in the world. A 7% molybdenum, very high nitrogen alloyed austenitic product with high mechanical strength. A potentially lean alternative to traditional wet-corrosion resistant nickel-based alloys.
EN 1.4652
ASTM type -
ASTM UNS S32654
Microstructure Austenitic
Typical applications
Product forms
Datasheet
Typical chemical composition, % by mass
C 0.01
Cr 24.0
Ni 22.0
Mo 7.3
N 0.50
Others 3.5Mn Cu
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Outokumpu Ultra Alloy 825 is a titanium stabilized austenitic nickel base alloy with an addition of copper.
W.-Nr. 2.4858
UNS N08825
ISO NW8825/ NiFe30Cr21Mo3
Microstructure Austenitic
Typical applications
Data sheet
Typical chemical composition, % by mass
C 0.01
Cr 23.0
Ni 39.5
Mo 3.2
Cu 1.7
Others Ti 0.75, Mn 0.8, Si 0.35, Al 0.1, Fe bal.
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Go directly to Grades
| EN 10028-7 | Flat products for pressure purposes – Stainless steels |
| EN 10088-2 | Stainless steels – Corrosion resisting sheet/ plate/strip for general and construction purposes |
| EN 10088-3 | Stainless steels – Corrosion resisting semi-finished products/bars/rods/wire/sections for general and construction purposes |
| EN 10088-4 | Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for construction purposes |
| EN 10088-5 | Technical delivery conditions for bars, rods, wire, sections and bright products of corrosion resistant steels for construction purposes |
| EN 10272 | Stainless steel bars for pressure purposes |
| EN 10283 | Corrosion resistant steel castings |
The most commonly used international product standards are given in the table above. For a full list of standards by product, see steelfinder.outokumpu.com
| ASTM A 193 / ASME SA-193 | Alloy and stainless steel bolts and nuts for high pressure and high temperature service |
| ASTM A 240 / ASME SA-240 | Cr and Cr-Ni stainless steel plate/sheet/strip for pressure purposes |
| ASTM A 276 | Stainless and heat-resisting steel bars/shapes |
| ASTM A 312 / ASME SA-312 | Seamless and welded austenitic stainless steel pipe |
| ASTM A 351 / ASME SA-351 | Steel castings, austenitic, duplex for pressure containing parts |
| ASTM A 358 / ASME SA-358 | Electric fusion-welded austenitic Cr-Ni alloy steel pipe for high temperature |
| ASTM A 409 / ASME SA-409 | Welded large diameter austenitic pipe for corrosive or high-temperature service |
| ASTM A 473 | Stainless steel forgings for general use |
| ASTM A 479 / ASME SA-479 | Stainless steel bars for boilers and other pressure vessels |
| ASTM A 743 | Castings, Fe-Cr-Ni, corrosion resistant for general application |
| ASTM A 744 | Castings, Fe-Cr-Ni, corrosion resistant for severe service |
| ASTM B 649 / ASME SB-649 | Bar and wire |
The most commonly used international product standards are given in the table above. For a full list of standards by product, see steelfinder.outokumpu.com
| NACE MR0175 | Sulfide stress cracking resistant material for oil field equipment |
| Norsok M-CR-630 | Material data sheets for 6Mo stainless steel |
| VdTÜV WB 473 | Austenitischer Stahl X 1 CrNiMoCuN 20 18 7 Werkstoff-Nr. 1.4547 |
| VdTÜV WB 537 | Stickstofflegierter austenitischer Stahl X2CrNiMnMoN 25-18-6-5 Werkstoff-Nr 1.4565 |
The most commonly used international product standards are given in the table above. For a full list of standards by product, see steelfinder.outokumpu.com
For the list of certificates and approvals by mill, see outokumpu.com/certificates
