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ASTM A789 UNS S31803 1.4462 Seamless and Welded Duplex Stainless Steel Tube

ASTM A789 UNS S31803 (1.4462) Seamless and Welded Duplex Stainless Steel Tube is a high-performance corrosion-resistant steel tube designed for demanding industrial applications. It is manufactured from duplex stainless steel (austenitic-ferritic structure), offering excellent strength, pitting resistance, and stress corrosion cracking resistance. This product is available in both seamless and welded forms, with a controlled averange/ minimum wall thickness to ensure structural integrity under high-pressure and harsh environments. It is widely used in oil & gas, chemical processing, desalination, and marine engineering.

1.Chemical & Mechanical Properties

Mechanical Properties

Key Mechanical Characteristics

• High Strength Characteristics
• Excellent Toughness
• Excellent Fatigue Performance
• Physical Properties

2. Key Adventages

• Superior Strength-to-Weight Ratio

High strength properties: Yield strength (≥450MPa) is twice that of 304 stainless steel, with tensile strength (620-795MPa) significantly exceeding conventional austenitic grades.

Weight reduction: Allows 20-30% material savings compared to standard stainless steels at equivalent pressure ratings.

• Outstanding Corrosion Resistance

Dual protection: Synergistic effect of Cr(21-23%)+Mo(2.5-3.5%)+N(0.08-0.20%)

Specialized resistance: Chloride stress corrosion cracking, pitting/crevice corrosion (PREN≥35), acid media

• Cost-Effectiveness

Lower lifecycle cost: 40-60% savings vs nickel alloys, 2-3x service life vs 316L

Easy installation: Excellent weldability (no PWHT required), CTE similar to carbon steel (13.5×10⁻⁶/℃)

• Versatile Performance

Wide temperature range: Stable performance from -50℃ to 300℃

Dual-phase benefits: Ferrite phase for strength + Austenite phase for toughness

3. Key Applications

• Oil & Gas

Subsea pipelines, X-mas tree components, LNG heat exchangers

• Chemical

Reactors, crystallizers, pickling equipment

• Desalination

High-pressure RO vessels, brine heaters

• New Energy

Geothermal casings, hydrogen storage

Selection Guidance

• High-strength+corrosion resistance combo
• Chloride-containing media
• Weight-sensitive high-pressure systems