Stainless steels for extremely corrosive environments

Ultra

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

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Outokumpu Ultra grades

Ultra 904L

High Ni and Mo austenitic grade with very high resistance to corrosion. Commonly used in chemical and petrochemical industry for handling medium concentrated sulphuric acid.

Typical applications
  • Process equipment in chemical industry
  • Petrochemical industry
  • Bleaching equipment in the pulp and paper industry
  • Flue gas cleaning
  • Desalination
  • Seawater handling
  • Hydrometallurgy
  • Food and beverage
  • Pharmaceuticals
  • Heat exchangers
Product forms
Chemical composition

Ultra 254 SMO®

Ultra 254 SMO is 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.

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
Product forms
Chemical composition

Ultra 317L

Ultra 317L is a Mo alloyed austenitic grade with higher corrosion resistance than “316L”. It is used, for instance, in chemical processing industry applications.

Typical applications
  • Chemical tankers
  • Pulp and Paper equipment
  • Condenser tubes and heat exchanger tubes
  • Equipment for the petrochemical industry
  • Flue-gas desulfurization equipment
Product forms
Chemical composition

Ultra 725LN

Ultra 725LN is a high Ni and Mo austenitic grade with similar corrosion resistance to Ultra 904L. Typically used in Urea applications. Available as plate only.

Typical applications
  • Urea applications
  • Pulp & Paper industry
  • Flue gas cleaning
  • Chemical industry
  • Pharmaceutical industry
Product forms
Chemical composition

Ultra 6XN

Ultra 6XN is 6% Mo, high Ni, and N alloyed austenitic grade with extremely high resistance to both uniform and localized corrosion. It is commonly used in applications to withstand chlorinated sea water also used in flue gas cleaning.

Typical applications
  • In applications to withstand chlorinated sea water
  • Flue gas cleaning
  • Process equipment in chemical industry
  • Bleaching equipment in the pulp and paper industry
  • Desalination
  • Seawater handling
  • Hydrometallurgy
  • Food and beverage
  • Pharmaceuticals
  • Heat exchangers
Product forms
Chemical composition

Sanicro® 35

Sanicro® 35 (UNS N08935)  is a newly developed alloy combining the best features of a high performance austenitic stainless steel and nickel based alloys. This grade has excellent corrosion resistance in combination with a high mechanical strength.

NOTE: Sanicro®35 is a trademark owned by Alleima AB and produced as plates and sheets by Outokumpu under a license agreement.

• Excellent resistance to pitting and crevice corrosion
• Excellent resistance to stress corrosion cracking (SCC)
• High resistance to uniform corrosion in acid and caustic environments
• High resistance to erosion-corrosion
• Very high mechanical strength
• Good weldability using nickel based alloy consumables.

Sanicro® 35 complies with NACE MR0175/ISO 15156-3 as a type 4a and 4c material, with significantly higher environmental limits than 6Mo grades like Ultra 254 SMO. Additionally, cold worked Sanicro® 35 (to 965 and 1240 MPa) has been tested in a NACE MR0175/ISO 15156 Test Level VI environment according to NACE TM0198 with no indication of SCC.

Typical applications
  • Plate heat exchangers
  • Tube, plate and shell of tubular heat exchangers
  • Scrubbers
  • Flue gas cleaning
  • Carbon capture
  • Sea water
  • Brine
  • Chlorinated acids
  • Chlorinated hydrocarbons
  • Chemical
  • Petrochemical
  • Refinery industry
  • Inorganic acids
  • Organic acids
  • Fine chemicals
  • Oil & gas equipment
  • Biorefining
  • Geothermal
Product forms
Chemical composition

Ultra Alloy 825

Outokumpu Ultra Alloy 825 (W.-Nr. 2.4858, UNS N08825, ISO NW8825) is a titanium stabilized austenitic nickel base alloy with an addition of copper.

  • Excellent resistance to stress corrosion cracking
  • Very good resistance in oxidizing and reducing acids
  • Moderate resistance to pitting and crevice corrosion
  • Good mechanical properties also at elevated temperatures
  • Reduced risk for sensitization when used in temperature ranges where this is a problem for stainless steels.

Outokumpu Ultra Alloy 825 is listed in ISO 15156-3 (NACE MR0175), materials for oil and gas production, and in NACE MR0103, materials resistant to sulfide stress cracking.

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
Product forms
Chemical composition
Made for offshore.

Tackle your sour gas challenge with Ultra Alloy 825

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For Extremely Corrosive Environments

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 Sanicro® 35. 

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.

Standards and approvals for Ultra range

 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

 

 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, visit Steel Finder.

 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

Outokumpu Ultra range downloads

Outokumpu Ultra range datasheet
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Sanicro® 35 datasheet
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Outokumpu Product Ranges chart
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Outokumpu Degerfors quarto plate product and dimension program
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Machining guidelines for high alloyed superaustenitic stainless steel 254 SMO®
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Machining guidelines for standard austenitic stainless steel grades
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