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 Seamless Tube (UNS S32550): ASTM A789
Ferralium 255 seamless tube (UNS S32550 / EN 1.4507) is supplied per ASTM A789 (Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service). Solution-annealed at 1100 °C with water quench. Per-heat MTC (EN 10204 type 3.2) documents chemistry, mechanical properties, ferrite content per ASTM E562, hydrostatic test result, and PREN calculation. Same ASTM A789 spec also covers Duplex 2205 tube (UNS S31803/S32205), Ferralium 255 sits in the super-duplex tier (PREN ≥ 40) above standard duplex 2205 (PREN ~35).
Tube Size Range
| OD range | Wall thickness range | Length | Form |
|---|---|---|---|
| 6 mm – 12 mm | 0.6 – 2.0 mm | up to 6 m | Seamless |
| 12 mm – 25 mm | 0.8 – 3.0 mm | up to 6 m | Seamless / welded |
| 25 mm – 50 mm | 1.5 – 5.0 mm | up to 12 m | Seamless / welded |
| 50 mm – 100 mm | 2.0 – 8.0 mm | up to 12 m | Seamless / welded |
| 100 mm – 200 mm | 3.0 – 15.0 mm | cut to length | Seamless |
ASTM A789 Inspection & Testing Requirements
- Chemical analysis per heat per ASTM A789 Table 1
- Tensile test per ASTM A370 / E8, yield ≥ 550 MPa, tensile ≥ 760 MPa, elongation ≥ 15%
- Hydrostatic test per A789 paragraph 13 (alternative: NDE per S2 ultrasonic when specified)
- Flattening test per A789 paragraph 11 (when specified)
- Reverse-flattening test per A789 paragraph 12 (welded tube)
- Ferrite content per ASTM E562 (35–55% per NORSOK M-630)
- Intergranular corrosion test per ASTM A923 method A or C (when specified)
- Critical Pitting Temperature per ASTM G48 method A (when specified for sour service)
- Hardness test (Rockwell HRC ≤ 32 for NACE MR0175)
- Per-heat Mill Test Certificate per EN 10204 type 3.1 or 3.2
Seamless vs Welded Ferralium 255 Tube
ASTM A789 covers both seamless and welded ferritic/austenitic stainless steel tubing. Welded tube manufactured by autogenous laser, plasma, or TIG welding (typically without filler) must meet weld-zone ferrite content 35–65% per NORSOK M-630. Seamless tube preferred for sour-service NACE MR0175 applications and pressure-cycled service. Heat-exchanger U-tube construction typically uses seamless; instrument tubing for hydraulic / pneumatic instrument loops typically welded.
Ferralium 255 Tube Applications
- Heat exchanger tube bundles for seawater service
- Subsea hydraulic control-line tubing
- Oil & gas instrument tubing in NACE MR0175 sour-service environments
- Chemical processing condenser tubes (HCl, H2SO4, brine service)
- Desalination heat-exchanger tubing
- Pulp & paper bleach plant heat-exchanger tubing
Ferralium 255 Tube vs Duplex 2205 Tube: Service Boundary
For tubing service exceeding standard-duplex limits (warm seawater > 30 °C, sour-gas above NACE MR0175 thresholds for Duplex 2205, reducing-acid heat exchanger duty), upgrade from Duplex 2205 tube (UNS S31803, PREN ~35) to Ferralium 255 tube (UNS S32550, PREN ≥ 40). Both grades supplied per identical ASTM A789 spec; super-duplex tube has higher chemistry / PREN / CPT margin and is preferred for high-criticality NORSOK M-650 offshore service. See Ferralium 255 vs Duplex 2205 upgrade guide.
TorqBolt Documentation & Compliance
Per-heat EN 10204 type 3.2 MTC with chemistry, mechanical properties, ferrite content, PREN calculation, hydrostatic test certificate. NORSOK M-650 QTR available on request per material data sheet MDS D55. NACE MR0175 / ISO 15156-3 sour-service compliance certified per heat. Contact info@torqbolt.com or +91-22-66157017.
Need Ferralium 255 tube? 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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