Surface Treatments
Certifications
- ISO 9001:2015
- NORSOK M-650
- NACE MR0175
- ISO 15156-3
- PED 2014/68/EC
- EN 10204 type 3.2
- AD 2000 W2/W7/W10
Duplex 2205 Chemical Composition (UNS S31803 / S32205)
Duplex 2205 is the most-specified standard duplex stainless steel grade, designated UNS S31803 (original 1980s composition) and UNS S32205 (modern narrowed composition introduced 1996). European designation: EN 1.4462 / X2CrNiMoN22-5-3. Nominal composition: 22 Cr – 5 Ni – 3 Mo – 0.15 N, balanced austenite-ferrite microstructure (35–55% ferrite per NORSOK M-630), PREN ~35 (below the super duplex PREN ≥ 40 threshold).
Duplex 2205 Chemical Composition Table
| Element | UNS S31803 (1980s) | UNS S32205 (1996+, narrowed) | EN 1.4462 |
|---|---|---|---|
| Carbon (C), max. | 0.030 | 0.030 | 0.030 |
| Manganese (Mn), max. | 2.00 | 2.00 | 2.00 |
| Phosphorus (P), max. | 0.030 | 0.030 | 0.035 |
| Sulphur (S), max. | 0.020 | 0.020 | 0.015 |
| Silicon (Si), max. | 1.00 | 1.00 | 1.00 |
| Chromium (Cr) | 21.0–23.0 | 22.0–23.0 | 21.0–23.0 |
| Nickel (Ni) | 4.5–6.5 | 4.5–6.5 | 4.5–6.5 |
| Molybdenum (Mo) | 2.5–3.5 | 3.0–3.5 | 2.5–3.5 |
| Nitrogen (N) | 0.08–0.20 | 0.14–0.20 | 0.10–0.22 |
| Copper (Cu) | not specified | not specified | not specified |
UNS S31803 vs UNS S32205, What Changed in 1996
The original UNS S31803 specification permitted a wider Cr (21–23%), Mo (2.5–3.5%), and N (0.08–0.20%) range, which allowed mills to produce heats at the LOW end, some heats hit PREN as low as 31. To guarantee PREN ≥ 35, the narrower UNS S32205 chemistry was introduced (Cr 22–23%, Mo 3.0–3.5%, N 0.14–0.20%). Most modern mill heats are dual-certified S31803 / S32205 by hitting the narrower S32205 ranges.
Ferralium 255 vs Duplex 2205 Composition
Ferralium 255 chemistry sits one tier above Duplex 2205 in the duplex / super duplex stainless steel family. The differences pushing PREN from ~35 (Duplex 2205) to ~40 (Ferralium 255) are: higher Cr (24–27 vs 21–23%), higher Mo (2.9–3.9 vs 2.5–3.5%), higher N (0.10–0.25 vs 0.08–0.20%), plus a 2% Cu addition that Duplex 2205 lacks. See Ferralium 255 vs Duplex 2205 upgrade guide for full selection criteria.
PREN Calculation for Duplex 2205
PREN = %Cr + 3.3 · %Mo + 16 · %N. With nominal Duplex 2205 composition (22 Cr, 3 Mo, 0.15 N): PREN = 22 + 9.9 + 2.4 = 34.3 minimum. Typical per-heat values 35–38. PREN < 40 places Duplex 2205 in the standard-duplex tier; super duplex grades (Ferralium 255, Super Duplex 2507, Zeron 100) sit above the PREN ≥ 40 threshold.
Spec References
- ASTM A479, bar, billet, shapes (UNS S31803, S32205)
- ASTM A240, plate, sheet, strip
- ASTM A789, seamless / welded ferritic-austenitic tube
- ASTM A790, seamless / welded ferritic-austenitic pipe
- ASTM A815, wrought fittings
- ASTM A182, forged flanges, fittings, valves
- EN 10088-3, long products (1.4462)
- EN 10222-5, forgings (1.4462)
Need Duplex 2205 stainless steel? Email info@torqbolt.com or WhatsApp +91-22-66157017 with form, dimensions, quantity, ASTM/EN spec, MTC level (3.1 / 3.2). NACE MR0175 sour-service stamp on every heat. NORSOK M-650 QTR on request. Per-heat EN 10204 type 3.2 MTC included with every consignment.
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