ASTM A790 UNS S31803 Seamless Pipes

ASTM A790 UNS S31803 Seamless Pipes

ASTM A790 UNS S31803 Seamless Pipes are duplex stainless steel pipes combining austenitic and ferritic microstructures to deliver exceptional strength and superior corrosion resistance. Manufactured without welded joints, these pipes provide uniform structure, high pressure tolerance, and enhanced reliability.

UNS S31803 offers excellent resistance to stress corrosion cracking, pitting, and crevice corrosion in chloride-containing environments. Its high mechanical strength makes it ideal for demanding applications in offshore, chemical, and industrial sectors.

Specifications

Standard	ASTM A790 / ASME SA790
Grade	UNS S31803
Material Type	Duplex Stainless Steel
Manufacturing Process	Hot Rolled / Cold Drawn Seamless
Size Range	1/8" NB to 24" NB
Wall Thickness	Schedule 5S to Schedule XXS
Length	6 Meters Standard / Custom Length
Surface Finish	Annealed & Pickled, Polished, Bright Finish
End Type	Plain End, Beveled End, Threaded

Key Benefits

• High Strength: Nearly double the yield strength of standard austenitic grades.
• Superior Corrosion Resistance: Excellent resistance to pitting and crevice corrosion.
• Stress Corrosion Crack Resistance: Performs well in chloride-rich environments.
• Excellent Toughness: Maintains strength and impact resistance.
• Cost Efficient: Higher strength allows thinner wall thickness, reducing material usage.

Chemical Composition (Typical)

Element	Percentage (%)
Carbon	0.03 Max
Chromium	21.0 – 23.0
Nickel	4.5 – 6.5
Molybdenum	2.5 – 3.5
Nitrogen	0.08 – 0.20

Applications

• Oil & Gas Processing
• Offshore Platforms
• Chemical Processing Plants
• Heat Exchangers
• Desalination Plants
• Marine Engineering

Quality Testing

• Hydrostatic Testing
• Ultrasonic Testing (UT)
• Radiographic Testing (RT)
• Positive Material Identification (PMI)
• Mechanical & Hardness Testing

Conclusion

ASTM A790 UNS S31803 Seamless Pipes provide an excellent combination of strength, durability, and corrosion resistance. Their duplex microstructure makes them highly suitable for aggressive environments where reliability and long-term performance are essential.