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
Ferralium 255 vs Zeron 100: Cu-Bearing vs W-Bearing Super Duplex Comparison
Ferralium 255 (UNS S32550) and Zeron 100 (UNS S32760) are both super duplex stainless steel grades meeting the PREN ≥ 40 threshold, but with distinct alloying chemistries that suit different service environments. Ferralium 255 is the Cu-bearing variant (~2% Cu) developed by Langley Alloys (UK); Zeron 100 is the W-bearing variant (~0.7% W) originally developed by Weir Materials. For full Zeron 100 grade reference, see the manufacturer-specialist site at zeron100.com (UNS S32760).
Q: How do Ferralium 255 and Zeron 100 differ in copper vs tungsten chemistry?
Composition Comparison: Cu vs W Differentiation
| Element | Ferralium 255 (S32550) | Zeron 100 (S32760) |
|---|---|---|
| Chromium (Cr) | 24.0–27.0 | 24.0–26.0 |
| Nickel (Ni) | 4.5–6.5 | 6.0–8.0 |
| Molybdenum (Mo) | 2.9–3.9 | 3.0–4.0 |
| Nitrogen (N) | 0.10–0.25 | 0.20–0.30 |
| Copper (Cu) | 1.5–2.5 | 0.5–1.0 |
| Tungsten (W) | none | 0.5–1.0 |
Q: What PREN does Ferralium 255 achieve compared to Zeron 100?
PREN Comparison
Ferralium 255 PREN = %Cr + 3.3·%Mo + 16·%N ≈ 40–42 typical per heat. Zeron 100 uses the modified PREW formula adding W weighted at 1.65: PREW = %Cr + 3.3(%Mo + 0.5·%W) + 16·%N ≈ 41–42 typical. Both grades comfortably exceed the PREN ≥ 40 super duplex threshold.
Q: How do the mechanical properties of Ferralium 255 and Zeron 100 compare?
Mechanical Properties Comparison
| Property | Ferralium 255 (S32550) | Zeron 100 (S32760) |
|---|---|---|
| Yield strength (Rp0.2), min | 550 MPa | 550 MPa |
| Tensile strength (Rm), min | 760 MPa | 750 MPa |
| Elongation (A5), min | 15% | 25% |
| Hardness (NACE MR0175), max | 32 HRC | 32 HRC |
| Charpy impact at −46 °C, min (NORSOK) | 45 J | 45 J |
Q: When should you choose Ferralium 255 over Zeron 100?
When to Choose Ferralium 255 vs Zeron 100
Choose Ferralium 255 when service involves reducing acids (dilute H2SO4, HCl, brines), chemical processing applications, or when the project specification requires a Cu-bearing super duplex grade.
Choose Zeron 100 when service involves the most aggressive seawater environments (warm seawater > 40 °C, high-velocity flow), or when the project specification (often UK / North Sea offshore) calls for the W-bearing variant. Both grades are interchangeable for standard NACE MR0175 sour-service applications and most marine seawater service.
Q: Which ASTM specifications cover both Ferralium 255 (UNS S32550) and Zeron 100 (UNS S32760)?
Spec Compliance
Both grades are covered by the same ASTM specifications: ASTM A479 (bar), ASTM A789 (tube), ASTM A790 (pipe), ASTM A815 (fittings), ASTM A182 (forgings/flanges). Both qualify under NORSOK M-650 with QTR per MDS D55, and NACE MR0175 / ISO 15156-3 for sour service. TorqBolt manufactures Ferralium 255 in Mumbai & Rajkot, India.
Need Ferralium 255 or Zeron 100? 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.
Satisfaction Survey
