DUplex and other High strength Stainless Steels

Forta

The Forta range contains duplex, H-Series and temper rolled austenitic and ferritic stainless steels that enable thinner structures and weight reduction (measured in Rp0.2 > 350 MPa. PRE 16 - 43). 

Duplex (austenitic-ferritic) stainless steel combines many of the best properties of austenitic and ferritic stainless steels: high strength, good corrosion resistance and enhanced resistance to stress- corrosion cracking (Rp0.2 > 400 MPa. PRE 26 - 43).

Forta DX 2205 (EN 1.4462) is the most well-known duplex product, offering very good resistance to uniform and localized corrosion and stress- corrosion cracking in combination with high mechanical strength. Super duplex Forta SDX 2507 (EN 1.4410), with higher corrosion resistance and mechanical strength than Forta DX 2205, is often used in extremely corrosive environments such as desalination, chemical or offshore subsea applications.

H-series are manganese containing fully austenitic stainless steels with high strength and high ductility (Rp0.2 > 400 MPa. PRE  21). Forta H400 (EN 1.4376) with lower nickel content has higher strength than standard austenitic stainless steels 304/304L and is a cost-effective solution for automotive lightweight applications.

Forta H500 (EN 1.4678) has a fully austenitic and non-magnetizable microstructure with significant strain-hardening due to twinning. With a yield strength higher than 500 MPa, it is a perfect lightweight alternative for safety- relevant components in the automotive and transportation industry. 

Temper-rolled stainless steels have high strength and high hardness (Rp0.2 > 350 MPa. PRE 16 - 25). Temper rolling means a controlled additional cold rolling process that is applied to standard austenitic and ferritic stainless steels and it increases the strength and surface hardness of the steels. The strength classification includes yield strength classes from CP350 up to CP1100 MPa and tensile strength classes from C700 up to C1900 MPa.

Temper-rolled austenitic stainless steel Forta 301/4310 (EN 1.4310) can reach the highest strength class. Forta H800 (EN 1.4678) and Forta H1000 (EN 1.4678) are the temper-rolled condition of Forta H500 and still non-magnetic. They offer higher resistance for crash-relevant parts and a cost-effective and price-stable solution in the automotive industry. 

Outokumpu Forta grades

Forta DX 2205

The most popular duplex product on the market. Offers very good resistance to uniform and localized corrosion and stress corrosion cracking in combination with high mechanical strength.

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  • EN: 1.4462
  • ASTM type: -
  • ASTM UNS: S32205
  • Microstructure: Duplex
Typical applications
  • Cargo tanks in chemical tankers
  • Pulp and paper industry applications such as digesters and process tanks
  • Oil and gas industry applications such as flanges, tubes, and pipes
  • Structural components in bridges
  • Flanges and valves
Chemical composition, % by mass
  • C: 0.02
  • Cr: 22.4
  • Ni: 5.7
  • Mo: 3.1
  • N: 0.17
  • Others: -

Forta LDX 2101

A lean-alloyed duplex product with good resistance to localized and uniform corrosion, as well as stress corrosion cracking, making it a good substitute for coated carbon steel in e.g. structural components and storage tanks. Also offers high mechanical strength and good machinability.

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  • EN: 1.4162
  • ASTM type: -
  • ASTM UNS: S32101
  • Microstructure: Duplex
Typical applications
  • Storage tanks
  • Household heaters
  • Structural components for floodgates and bridges, or rebar for concrete structures
  • Pulp and paper industry applications such as digesters and components for paper machines
  • Flanges and valves
Chemical composition, % by mass
  • C: 0.03
  • Cr: 21.5
  • Ni: 1.5
  • Mo: 0.3
  • N: 0.22
  • Others : 5 Mn Cu

Forta DX 2304

A duplex product with a leaner alloying composition than Forta DX 2205. It has good resistance to localized and uniform corrosion, as well as stress corrosion cracking, combined with high mechanical strength.

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  • EN: 1.4362
  • ASTM type: -
  • ASTM UNS: S32304
  • Microstructure: Duplex
Typical applications
  • Pulp and paper industry applications
  • Blast walls on oil platforms
  • Flanges and valves
Chemical composition, % by mass
  • C: 0.02
  • Cr: 23.0
  • Ni: 4.8
  • Mo: 0.3
  • N: 0.10
  • Others: Cu

Forta EDX 2304

An enhanced version of Forta DX 2304 with better corrosion resistance and higher mechanical strength.

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  • EN: 1.4362
  • ASTM type: -
  • ASTM UNS: S32304
  • Microstructure: Duplex
Typical applications
  • Offshore topside structural components
  • Tank applications
  • Flanges and valves
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 23.8
  • Ni: 4.3
  • Mo: 0.5
  • N: 0.18
  • Others: Cu

Forta LDX 2404

A low-nickel, high-nitrogen duplex product with higher mechanical strength than Forta DX 2205. Offers very good resistance to localized and uniform corrosion, as well as stress corrosion cracking.

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  • EN: 1.4662
  • ASTM type: -
  • ASTM UNS: S82441
  • Microstructure: Duplex
Typical applications
  • Storage tanks
  • Structural components for flood and sluice gates
  • Mining industry applications such as dewatering equipment
  • Flanges and valves
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 24.0
  • Ni: 3.6
  • Mo: 1.6
  • N: 0.27
  • Others: 3Mn Cu

Forta SDX 100

A super duplex product with higher corrosion resistance and mechanical strength than Forta DX 2205. Often used in extremely corrosive environments such as desalination, chemical, or offshore subsea applications.

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  • EN: 1.4501
  • ASTM type: -
  • ASTM UNS: S32760
  • Microstructure: Duplex
Typical applications
  • Desalination plants
  • Industrial piping
  • Scrubbers
  • Tubular products for oil and gas applications
  • Deep-sea pipelines
  • Flanges and valves
Product forms
Chemical composition
  • C: 0.02
  • Cr: 25.4
  • Ni: 6.9
  • Mo: 3.8
  • N: 0.27
  • Others: W Cu

Forta SDX 2507

A super duplex product with higher corrosion resistance and mechanical strength than Forta DX 2205. Often used in extremely corrosive environments such as desalination, chemical, or offshore subsea applications.

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  • EN: 1.4410
  • ASTM type: -
  • ASTM UNS: S32750
  • Microstructure: Duplex
Typical applications
  • Desalination plants
  • Industrial piping
  • Scrubbers
  • Tubular products for oil and gas applications
  • Deep-sea pipelines
  • Flanges and valves
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 25
  • Ni: 7.0
  • Mo: 4.0
  • N: 0.27
  • Others: -

Forta H400

Forta H400 has higher strength than standard 304/4301 and a lower nickel content, making it a cost-effective and lightweight austenitic product for the automotive industry. It has been used in automotive applications for over 10 years.

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  • EN: 1.4376
  • ASTM type: -
  • ASTM UNS: -
  • Microstructure: Austenitic
Usage
  • Cross members
  • Strut domes
  • Bumpers
Typical chemical composition, % by mass
  • C: 0.04
  • Cr: 17.5
  • Ni: 4.0
  • Mo: -
  • N: 0.20
  • Others: 6.8Mn

Forta 430/4016

A classic 16% chromium ferritic stainless steel used in mildly corrosive environments.

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  • EN: 1.4016
  • ASTM type: 430
  • ASTM UNS: S43000
  • Microstructure: Ferritic
Typical applications
  • Automotive components
  • Structural applications
  • Tanks
Typical chemical composition, % by mass
  • C: 0.05
  • Cr: 16.2
  • Ni: -
  • Mo: -
  • N: -
  • Others: -

Forta 301LN/4318

A low-carbon, nitrogen alloyed alternative to Forta 301/4310.

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  • EN: 1.4318
  • ASTM type: 301LN
  • ASTM UNS: S30153
  • Microstructure : Austenitic
Typical applications
  • Vehicle chassis
  • Profiles
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 17.7
  • Ni: 6.5
  • Mo: -
  • N: 0.14
  • Others: -

Forta 301/4310

A lower chromium and nickel alternative to Forta 304/4301 with high work hardening capacity.

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  • EN: 1.4310
  • ASTM type: 301
  • ASTM UNS: S30100
  • Microstructure: Austenitic
Typical applications
  • Automotive components
  • Cable connectors
  • Springs
  • Window frames
  • Commercial appliances
Typical chemical composition, % by mass
  • C: 0.10
  • Cr: 17.0
  • Ni: 7.0
  • Mo: -
  • N: -
  • Others: -

Forta 304/4301

Forta 304/4301 is a classic 18% chromium, 8% nickel austenitic stainless steel. It’s an all-purpose product with good corrosion resistance and is suitable for a wide variety of applications.

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  • EN: 1.4301
  • ASTM type: 304
  • ASTM UNS: S30400
  • Microstructure: Austenitic
Typical applications
  • Beer kegs
  • Cutlery
  • Automotive components
  • Tanks and vessels
  • Furniture
  • Structural applications
Typical chemical composition, % by mass
  • C: 0.04
  • Cr: 18.1
  • Ni: 8.1
  • Mo: -
  • N: -
  • Others: -

Forta 304L/4307

Forta 304L/4307 is a low-carbon alternative to Forta 304/4301 and is suitable for a wide variety of applications.

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  • EN: 1.4307
  • ASTM type: 304L
  • ASTM UNS: S30403
  • Microstructure: Austenitic
Typical applications
  • Beer kegs
  • Cutlery
  • Automotive components
  • Tanks and vessels
  • Furniture
  • Structural applications
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 18.1
  • Ni: 8.1
  • Mo: -
  • N: -
  • Others: -

Forta 316/4401

A normal-carbon alternative to Forta 316L/4404 that is widely used for various applications.

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  • EN: 1.4401
  • ASTM type: 316
  • ASTM UNS: S31600
  • Microstructure: Austenitic
Typical applications
  • Automotive components
  • Tanks and vessels
Typical chemical composition, % by mass
  • C: 0.04
  • Cr: 17.2
  • Ni: 10.1
  • Mo: 2.1
  • N: -
  • Others: -

Forta 316L/4404

A normal-carbon alternative to Forta 316L/4404 that is widely used for various applications.

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  • EN: 1.4404
  • ASTM type: 316L
  • ASTM UNS: S31603
  • Microstructure : Austenitic
Typical applications
  • Automotive components
  • Tanks and vessels
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 17.2
  • Ni: 10.1
  • Mo: 2.1
  • N: -
  • Others: -

Forta 316plus

Forta 316plus is a cost-efficient, 21Cr lower-nickel/molybdenum alternative to traditional molybdenum austenitics like Forta 316L/4404.

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  • EN: 1.4420
  • ASTM type: -
  • ASTM UNS: S31655
  • Microstructure: Austenitic
Typical applications
  • Automotive components
  • Tanks and vessels
Typical chemical composition, % by mass
  • C: 0.02
  • Cr: 20.3
  • Ni: 8.6
  • Mo: 0.7
  • N: 0.19
  • Others : -

Forta 316Ti/4571

A titanium-stabilized, molybdenum-alloyed austenitic alternative to Forta 316L/4404 – mainly used in Germany.

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  • EN: 1.4571
  • ASTM type: 316Ti
  • ASTM UNS: S32100
  • Microstructure: Austenitic
Typical applications
  • Heating technology
  • Profiles
Typical chemical composition, % by mass
  • C: 0.04
  • Cr: 16.8
  • Ni: 10.9
  • Mo: 2.1
  • N: -
  • Others: Ti

Standards and approvals

EN ISO 18286     Hot-rolled stainless steel plates – Tolerances on dimensions and shape  
EN 10051 Hot-rolled steel strip.
EN 10088-1 Stainless steels – list of stainless steels 
ISO 15510 Stainless steels – chemical composition 
EN ISO 9445 Cold-rolled stainless narrow strip, wide strip, plate/sheet and cut lengths. 
ASTM A 480 General requirements for flat-rolled stainless and heat resisting steel 
ASTM A 959 Harmonized standard grade compositions for wrought stainless steels 
ASME IID Materials – Physical properties tables 


 EN 10028-7   Flat products for pressure purposes – Stainless steels
 EN 10088-2  Stainless steels – sheet/plate and strip for general purposes
 EN 10088-3  Stainless steels – semi-finished products, bars, rods sections for general purposes
 EN 10088-4  Technical delivery conditions for sheet/plate and strip
 EN 10088-5  Technical delivery conditions for bars, rods wire, sections and bright products of corrosion resisting steels for construction purposes
 EN 10095  Heat resisting steels and nickel alloys
 EN 10151  Stainless steel strip for springs
 EN 10302  Creep resisting steels, nickel and cobalt alloys
 ASTM A 167  Stainless and heat-resisting Cr-Ni steel plate, sheet, and strip
 ASTM A 176  Stainless and heat-resisting Cr steel plate, sheet, and strip
 ASTM A 240  Cr and Cr-Ni stainless steel plate, sheet and strip for pressure vessels
 ASTM A276  Stainless steel and heat resisting steel bars and shapes
 ASTM A479/479M  Stainless steel bars for boilers/pressure vessels
 ASTM A493  Stainless steel and heat-resisting steel rod and wire for cold heading and forging
 ASTM A555  General requirements for stainless and heat resistant steel wire and wire rod
 ASTM A 666  Austenitic stainless steel sheet, strip, plate, bar for structural and architectural applications
 ASME IIA  Materials. Part A – Ferrous Material Specifications
      

Forta DX 2304, Forta DX 2205, and Forta SDX 2507 are listed in EN 10028-7:2007.

European material approval EAM 0045-01:2012/01 for Forta LDX 2101 is available for cold rolled 0.5-6.4 mm and hot rolled 3.0–10.0 mm.

In ASME II-D 2013, Forta DX 2205 (S31803 and S32205). Forta EDX 2304 (S32304), Forta SDX 100 (S32760) and Forta SDX 2507 (S32750) are listed for general use in the temperature range -30 – 316 °C. Data for Forta LDX 2101 and Forta LDX 2404 can be found in ASME code case 2418-1 and 2780 respectively.


Outokumpu meets the most common certifications and approvals around the world, including:

  • 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)

Forta range use cases and articles

Case STILRIDE – Carbon footprint LCA

STILRIDE motors ahead with sustainable stainless steel

Article

An exhilarating journey in duplex stainless steel

Case Stainless Steel Yachts

Maximal performance with duplex stainless steel

Article

Customer education key to adoption of duplex grades

Article

Outokumpu delivers stainless steel to critical sluice gates

Case Gårda Dämme

Floodgates to fight rising sea levels

Article

What if we could safely control the water flow?

Case Tammerkoski

Securing floodgates for two centuries

Case Pooley Bridge

Bridging to the future

Outokumpu Forta range downloads

Outokumpu Forta duplex datasheet
Outokumpu Forta Temper rolled stainless steels
Outokumpu Product Ranges chart
Machining guidelines for Forta DX2205
Machining guidelines for Forta DX2304
Machining guidelines for Forta LDX2404®
Machining guidelines for Forta SDX 2507
Machining guidelines for Forta LDX 2101
Machining guidelines for standard austenitic stainless steel grades