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Material Specification

Ferralium 255

Ferralium 255 Fasteners
Original High-Strength 25% Cr Super Duplex Alloy (UNS S32550 / EN 1.4507)

Super Duplex Steel Ferralium 255 Fasteners

Buy Ferralium® 255 (UNS S32550 / DIN EN 1.4507 / Alloy 255 / F61) bolts, studs, nuts, and severe-service fasteners from Exotic Alloy, conforming to ASTM A1082, ASTM A276, ASTM A479, and NACE MR0175 / ISO 15156. Ferralium 255 is the pioneer super duplex stainless steel, combining 25% chromium with 2% copper and high nitrogen, providing extraordinary resistance to sulfuric, phosphoric, and organic acids alongside a guaranteed PREN ≥ 42.

Exotic Alloy manufactures Ferralium 255 heavy hex bolts, socket screws, double-end stud bolts, and custom drawing components. Its superior mechanical hardness, yield strength (≥ 550 MPa), and outstanding erosion-corrosion resistance make it the benchmark alloy for marine hardware, acid processing, and subsea fasteners.

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Ferralium 255 Bolting Products

Ferralium 255 Specifications & Standards

  • ASTM A1082 / A276 / A479
  • UNS S32550 / Ferralium® 255
  • NACE MR0175 / ISO 15156
  • DIN EN ISO 10088-3 (1.4507)
  • X2CrNiMoCuN25-6-3
  • ISO 3506-1
Ferralium 255 Material Datasheet

Ferralium 255 Properties

Chemical Composition (Ferralium 255)
Elements C Mn P S Si Cr Ni Mo Cu N
Min % - - - - - 24.00 4.50 2.90 1.50 0.10
Max % 0.040 1.50 0.040 0.030 1.00 27.00 6.50 3.90 2.50 0.25
Mechanical Properties (Ferralium 255)
Condition / Heat Treatment Tensile Strength (MPa) Yield Strength (MPa) Elongation (%) Hardness
Solution Annealed (Bar / Fasteners) 760 - 950 550 15 - 25 % 290 - 320 HB / 32 HRC

Ferralium 255 Characteristics

  • 2% copper content delivers unmatched resistance to sulfuric and wet-process phosphoric acids.
  • High minimum yield strength (550 MPa / 80 ksi) with superior abrasion and erosion resistance.
  • Guaranteed PREN ≥ 42 providing total immunity to pitting in hot marine environments.
  • Excellent resistance to stress corrosion cracking (SCC) in sour gas service.
  • High surface hardness reducing wear in dynamic bolting and rotating components.

Applications

  • Phosphoric acid fertilizer evaporators, agitators, and pumps.
  • Marine hardware, shafting, cutlass bearings, and deck fasteners.
  • Geothermal power wellhead valves and piping fasteners.
  • Wastewater processing, centrifuges, and sludge handling pumps.
  • Subsea Christmas trees, flowline flanges, and structural clamps.