Ultra

Stainless steels for extremely corrosive environments

Browse Ultra range specifications Visit Stainless Steel Finder

The Ultra range is best choice for wet corrosion challenges of your application. It contains stainless steel products for extremely corrosive environments.

More forms to choose from

We offer nickel-based alloy Ultra Alloy 825 as sheet, quarto plate, wire rod and welding strip, and as hot and cold rolled coils up to a width of 1,500 mm.

Read more about our Alloy 825 and download white paper

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Ultra

The Ultra range includes highly alloyed austenitic grades that are designed for extremely corrosive environments with PRE of more than 27.

The Ultra range includes our key products Ultra Alloy 825 (EN 2.4858), Ultra 904L (EN 1.4539) and Ultra 254 SMO (EN 1.4547) as well as several alternatives, for example Ultra 654 SMO (EN 1.4652) , the most corrosion-resistant stainless steel in the world, for your most specific applications.

The Ultra range is the best choice when you need material for extremely corrosive environments where standard grades like Core 304L/4307 or Supra 316L/4404 are not sufficient for the corrosion challenges of your application. 

The Ultra range stainless steels are not just excellent in corrosion resistance, but the strength and elongation properties of the Ultra range are similar or better in comparison with conventional austenitic stainless steels. The addition of nitrogen to Ultra grades such as Ultra 254 SMO gives them higher yield and tensile strength. Despite the greater strength of these steels, they offer very good possibilities for cold as well as hot forming. Ultra range steels are well suited for welding, and the methods used for welding conventional austenitic steels can also be used on these products.

Typical applications for Ultra range grades are:

  • chemical and petrochemical industry
  • maritime exhaust gas cleaning
  • heat exchangers
  • applications requiring resistance for chlorinated seawater.

Ultra Alloy 825 is a Ti-stabilized austenitic nickel base alloy used in the oil and gas industry in piping systems, petroleum refinery equipment and sour gas service systems. Ultra 904L is used in 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.

Ultra range grades can be used in a wide range of applications supported with a broad selection of surface finishes from mills and service centers.

See the full list of Ultra grades below

Outokumpu Ultra grades

Ultra Alloy 825 nickel base alloy

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

  • Components in sour gas service
  • Offshore oil and gas piping systems
  • Equipment in petroleum refineries
  • Heating coils
  • Heat exchangers
  • Tanks
  • Scrubbers
  • Chemical processing equipment
  • Food process equipment
  • Nuclear industry equipment

Data sheet

Download Ultra Alloy 825 datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

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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Ultra 904L stainless steel

Ultra 904L is a high-nickel and molybdenum austenitic stainless steel with very high corrosion resistance. It 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

  • Chemical and petrochemical industry equipment such as pipes, heat exchangers, tanks, and reactor vessels
  • Sulfuric acid handling
  • Flanges and valves

Datasheet

Download Ultra range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

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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Ultra 317L stainless steel

Ultra 317L is 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

  • Chemical processing industry

Data sheet

Dowload Ultra range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.02

Cr 18.2

Ni 13.7

Mo 3.1

N -

Others -

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Ultra 725LN stainless steel

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

  •  Urea applications

Product forms

Datasheet

Download Ultra range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

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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Ultra 6XN stainless steel

Ultra 6XN is 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

  • Applications requiring resistance to chlorinated seawater
  • Flue gas cleaning

Datasheet

Download Ultra range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

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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Ultra 654 SMO stainless steel

Ultra 654 SMO is 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

  • Pressurized and erosive systems handling chlorinated seawater at higher temperatures
  • Plate heat exchangers
  • Flue gas cleaning applications

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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Ultra 254 SMO stainless steel

A 6 % molybdenum and nitrogen-alloyed austenitic stainless steel with extremely high resistance to both uniform and localized corrosion. This product was developed especially for oil and gas offshore platforms and the pulp and paper industry.

EN 1.4547

ASTM type -

ASTM UNS S31254

Microstructure Austenitic

Typical applications

  • Applications requiring resistance to chlorinated seawater
  • Flue gas cleaning
  • Maritime exhaust gas cleaning (EGC)
  • Bleaching equipment in the pulp and paper industry
  • Flanges and valves

Datasheet

Download Ultra range datasheet for more information on corrosion resistance, mechnanical properties, physical properties and fabrication

Typical chemical composition, % by mass

C 0.01

Cr 20.0

Ni 18.0

Mo 6.1

N 0.20

Others Cu

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Ultra 3964 stainless steel

Non-magnetic, high strength austenitic stainless steel with excellent corrosion resistance

EN WL 1.3964

ASTM type -

ASTM UNS -

Microstructure -

Typical applications

  • Marine application

Chemical composition, % by mass

C 0.02

Cr 20.4

Ni 15.4

Mo 3.3

N 0.26

Others Mn

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Ultra 3964 stainless steel

Non-magnetic, high strength austenitic stainless steel with excellent corrosion resistance

EN WL 1.3964

ASTM type -

ASTM UNS -

Microstructure -

Typical applications

  • Marine application

Chemical composition, % by mass

C 0.02

Cr 20.4

Ni 15.4

Mo 3.3

N 0.26

Others Mn

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Go directly to Outokumpu Ultra grades

Standards und Zulassungen für die Kategorie Ultra

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

  • AD 2000 Merkblatt
  • Approval of Material Manufacturers
  • Factory Production Control Certificate
  • ISO 9001
  • ISO 14001
  • ISO 50001
  • ISO/TS 16949
  • NORSOK
  • OHSAS 18001
  • Pressure Equipment Directive (PED) 

For the list of certificates and approvals by mill, see outokumpu.com/certificates

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