Exotic Metals LLP

Duplex and Super Duplex Stainless Steel

Duplex Stainless Steel (2205 / S31803 / S32205) – Exotic Metals LLP

Alloy 2205 is the most widely used duplex grade. It was developed to combat common corrosion problems encountered with 300-series stainless steels. Due to its high chromium and molybdenum content, it offers superior resistance to pitting and crevice corrosion in most environments.

S31803 vs S32205: While S31803 was the original duplex 22Cr alloy, S32205 is a nitrogen-enhanced version with higher Cr, Mo, and N levels for improved corrosion resistance. Most modern materials are dual-certified to meet both.

Mechanical Properties (Minimum Values)

Grade UNS Number Tensile (MPa) Yield (MPa) Elongation (%) Hardness (HB)
Duplex 2205 S31803 ≥ 620 ≥ 450 25% 293 Max
Duplex 2205 S32205 ≥ 655 ≥ 450 25% 293 Max

Super Duplex Stainless Steel (2507 / S32750 / S32760)

Super Duplex grades are highly alloyed steels designed for service in extremely corrosive conditions like warm seawater. They possess a Pitting Resistance Equivalent Number (PREN) of > 40.

Super Duplex Grades

  1. 2507 (S32750): The most common Super Duplex grade. Known for its high thermal conductivity and low coefficient of thermal expansion
  2. S32760: An enhanced Super Duplex grade that includes Copper and Tungsten in its chemistry. This provides superior resistance to mineral acids and is frequently used in flue-gas desulfurization (FGD) and subsea applications

Chemical Composition Comparison (%)

Element Duplex 2205 Super Duplex 2507 Super Duplex S32760
Chromium (Cr) 22.0 – 23.0 24.0 – 26.0 24.0 – 26.0
Nickel (Ni) 4.5 – 6.5 6.0 – 8.0 6.0 – 8.0
Molybdenum (Mo) 3.0 – 3.5 3.0 – 5.0 3.0 – 4.0
Nitrogen (N) 0.14 – 0.20 0.24 – 0.32 0.20 – 0.30
Other — — Cu: 0.5–1.0 / W: 0.5–1.0

Product Range & Dimensions

Exotic Metals LLP stocks and fabricates these grades in various industrial formats:

Product Forms

  1. Piping & Tubing: Seamless & Welded Pipe (1/2" to 24" NB), SCH 10S to SCH XXS
  2. Long Products: Round Bar (3mm to 800mm), Hex Bar, Square Bar, Forged Rods
  3. Flat Products: Plates (up to 80mm thick), Sheets (Cold Rolled 0.5mm+), Coils, Strips
  4. Hardware & Fittings: Flanges (WNRF, SWRF), Buttweld Fittings, Forged Fittings, Fasteners

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Weight Chart: Duplex & Super Duplex Round Bar (Theoretical kg/m)

Diameter (mm) Duplex 2205 Super Duplex (2507/S32760)
12 mm 0.89 0.91
25 mm 3.85 3.93
50 mm 15.41 15.70
100 mm 61.65 62.80

Key Properties

  1. Temperature Note: These grades are particularly suitable for applications in the -50°C to +300°C range. Exposure to temperatures above 300°C can cause embrittlement of the micro-constituents
  2. Strength: Roughly double the yield strength of 316L, allowing for thinner wall sections and weight savings
  3. Corrosion: Exceptional resistance to pitting, crevice corrosion, and stress corrosion cracking (SCC)
  4. Weldability: Good weldability using matching filler metals (e.g., E2209 for 2205) and controlled heat input

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Contact Details

Address :

Shop No-3, 327, Makharia House, Sardar Vallabhbhai Patel Rd, opp. 7th Lane Khetwadi Main Road, Charni Road East, Khetwadi, Sicka Nagar, Mumbai, Maharashtra 400004

Phone Number :

Mobile No: +91 75065 95134
Landline No: +91 22 6615 9052

Email :

info@exoticmetalsllp.com

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