Duplex Stainless Steel Materials for Pipes, Pipe Fittings, Flanges and Stud Bolts
Duplex stainless steel is widely used in industrial piping systems due to its excellent corrosion resistance, high strength, and superior resistance to chloride stress corrosion cracking. Duplex stainless steel materials are commonly used to manufacture pipes, pipe fittings, flanges, stud bolts, and other piping components used in aggressive and corrosive environments.
Duplex stainless steel combines the advantages of austenitic and ferritic stainless steel, providing higher strength and improved corrosion resistance compared to standard stainless steel grades.
These materials are widely used in industries such as offshore oil and gas, petrochemical plants, desalination systems, marine engineering, and chemical processing facilities.
Duplex stainless steel piping components are manufactured according to international standards including ASTM, ASME, DIN, EN, and GOST to ensure compatibility with global industrial pipeline systems.
Duplex Stainless Steel Grades
Duplex stainless steel materials used in piping systems are defined by internationally recognized material standards.
Duplex Stainless Steel Pipes
Common duplex stainless steel pipe materials include:
- ASTM A790 UNS S31803 – Duplex stainless steel pipe
- ASTM A790 UNS S32205 – Improved duplex stainless steel pipe
- ASTM A790 UNS S32750 – Super duplex stainless steel pipe
- ASTM A790 UNS S32760 – Super duplex stainless steel pipe for severe environments
These pipes provide excellent resistance to corrosion in seawater, chloride environments, and aggressive chemical applications.
Duplex Stainless Steel Pipe Fittings
Duplex stainless steel pipe fittings are used to connect and redirect piping systems in corrosive environments.
Common material standards include:
- ASTM A815 UNS S31803 – Duplex stainless steel pipe fittings
- ASTM A815 UNS S32205 – Improved duplex stainless steel fittings
- ASTM A815 UNS S32750 – Super duplex stainless steel fittings
- ASTM A815 UNS S32760 – Super duplex stainless steel fittings
Common fitting types include:
- Butt Weld Elbow
- Butt Weld Tee
- Butt Weld Reducer
- Butt Weld Cap
These fittings are typically manufactured according to ASME B16.9 standards.
Duplex Stainless Steel Flanges
Duplex stainless steel flanges are widely used in offshore and chemical processing pipelines due to their high strength and corrosion resistance.
Common material standards include:
- ASTM A182 F51 – Duplex stainless steel flanges
- ASTM A182 F60 – Improved duplex stainless steel flanges
- ASTM A182 F53 – Super duplex stainless steel flanges
- ASTM A182 F55 – Super duplex stainless steel flanges for severe environments
Typical flange types include:
- Weld Neck Flange (WN)
- Blind Flange (BL)
- Slip-On Flange (SO)
- Socket Weld Flange (SW)
- Threaded Flange (TH)
- Lap Joint Flange (LJ)
These flanges are manufactured according to ASME B16.5 and ASME B16.47 standards.
Duplex Stainless Steel Stud Bolts
Stud bolts used in duplex stainless steel piping systems must provide high strength and corrosion resistance.
Common standards include:
- UNS S32205 – Duplex Stainless steel stud bolts
- UNS S32750 – Super Duplex Stainless steel stud bolts
Nuts are commonly manufactured according to:
- UNS S32205/UNS S32750
Duplex Stainless Steel Chemical Composition
Typical chemical composition for duplex stainless steel materials such as UNS S31803 / S32205.
| Element | Carbon | Chromium | Nickel | Molybdenum | Nitrogen |
|---|---|---|---|---|---|
| Max % | 0.03 | 21–23 | 4.5–6.5 | 2.5–3.5 | 0.08–0.20 |
This chemical composition provides excellent corrosion resistance and mechanical strength.
Mechanical Properties of Duplex Stainless Steel
Typical mechanical properties for duplex stainless steel piping materials.
| Property | Value |
|---|---|
| Tensile Strength | ≥ 620 MPa |
| Yield Strength | ≥ 450 MPa |
| Elongation | ≥ 25% |
Duplex stainless steel offers approximately twice the strength of standard austenitic stainless steels.
Duplex Stainless Steel Standards for Piping Components
| Component | Type | ASTM / Material Standard | ASME Dimension Standard | DIN Standard | EN Standard | GOST Standard |
|---|---|---|---|---|---|---|
| Pipes | Seamless / Welded Pipe | ASTM A790 | ASME B36.19 | DIN 17456 | EN 10216 | — |
| Pipe Fittings | Elbow / Tee / Reducer | ASTM A815 | ASME B16.9 | DIN 2605 / 2615 | EN 10253 | — |
| Flanges | Weld Neck / Slip On / Blind | ASTM A182 F51 / F53 | ASME B16.5 / B16.47 | DIN 2631 | EN 1092-1 | — |
| Bolting | Stud Bolts | ASTM A193 B8M | ASME B18 | DIN 976 | EN ISO 898 | — |
| Gaskets | Spiral Wound / RTJ | Various materials | ASME B16.20 / B16.21 | DIN 2690 | EN 1514 | — |
Typical Size Range
Duplex stainless steel pipes are typically available in:
NPS 1/2″ – 48″
DN15 – DN1200
Schedule 10 – Schedule XXS
Flanges are typically produced in:
Class 150 – Class 2500
Applications
Duplex stainless steel piping components are widely used in:
- Offshore oil and gas platforms
- Desalination plants
- Chemical processing plants
- Marine engineering
- Petrochemical industries
The excellent corrosion resistance and high strength of duplex stainless steel make it ideal for chloride-rich and aggressive environments.
Frequently Asked Questions
What is duplex stainless steel used for?
Duplex stainless steel is widely used in piping systems requiring high strength and excellent corrosion resistance, particularly in offshore and marine environments.
What is ASTM A790?
ASTM A790 is a specification for seamless and welded duplex stainless steel pipes used in corrosive environments.
What is ASTM A182 F51?
ASTM A182 F51 is a duplex stainless steel material specification commonly used for forged flanges and fittings.
