Ferralium 255 – SD50 HS110 (UNS S32550 110ksi)

Description:

Ferralium® 255 – SD50 HS110 is a higher strength super duplex stainless steel supplied in the strain hardened condition (Condition S). By precise further processing, it achieves significantly raised yield and tensile strengths whilst still retaining good levels of impact strength. Typically offered in tubular form, the machined bar will serve as coupling material, suitable for subsequent processing to coupling stock, couplings and other tubular goods as outlined in API 5CRA / 5CT. It therefore provides a cost-effective alternative for applications that previously used higher cost alloys. The production route allows smaller quantities to be economically manufactured against competitive lead times.

As a 25% Cr alloy, with significant additions of copper, it offers excellent corrosion resistance in a wide variety of corrosive chemicals including sulphuric, nitric and phosphoric acid. In seawater and other chloride containing environments it also provides outstanding resistance to pitting and crevice corrosion, with Critical Pitting Temperature exceeding 50°C. Excellent ductility and impact strength at both ambient and sub-zero temperatures combine with a high resistance to abrasion, erosion and cavitation erosion.

Ferralium® 255 – SD50 HS110 builds upon the Ferralium® 255 – SD50 product which is listed in NACE MR 01 75 for sour service and has gained ASME Approval for Pressure Vessel applications. It is tested to the highest degree using tests designed to guarantee that our trade-marked product possesses high integrity, correct phase balance and the absence of sigma and other deleterious phases.

Key Features:

  • Ferralium® was originally developed in 1960’s, pioneering the addition of nitrogen, to create the first super duplex stainless steel
  • Continuously developed through 1990’s to extend PREN > 40, and more recently to increase mechanical properties
  • Pitting Resistance Equivalent (PREN) >40, indicating outstanding resistance to pitting and crevice corrosion
  • Very low levels of sulphur minimise the likelihood of inclusions as sites for potential pitting corrosion
  • Higher copper content provides self-healing effect at sites of pitting to inhibit further growth
  • Now available in a high strength variant, achieving proof stress exceeding 110ksi (758N/mm2) in diameters up to 6 ½“

Applications:

  • Ferralium® 255 – SD50 is widely specified in the Oil & Gas industry for pumps, valves, wellhead and subsea equipment
  • Ferralium® 255 – SD50 HS110 has been developed for applications currently only able to be supplied from tubular goods in more costly nickel alloys
  • Coupling material for conversion to coupling stock, couplings, collars and associated components

Chemical Composition:

Cr Ni Mo Co Nb (+Ta) Ti V W Cu C Mn N Si P S Fe Al
Min 24.50 5.50 3.10 1.50 0.80 0.20
Max 26.50 6.50 3.80 2.00 0.025 1.20 0.25 0.70 0.025 0.005 Balance

Mechanical Properties:

Bars up to and including 6.5” diameter or section
0.2% Proof Stress 758 - 965 N/mm2 110-140 ksi
Tensile Strength 862 N/mm2 125 ksi
Elongation, 5.65√S0 and 4D 16%
Hardness (Rockwell C) < 35
Impact Strength (-10degC), Transverse 40J av (27J min) 30 ft.lb av (20 ft.lb min)

Notes:

  1. Testing shall be carried out in accordance with ASTM A370 or EN ISO 6892-1 (tensile), EN ISO 6506-1 (hardness)
  2. Minimum properties quoted (tested at room temperature in a longitudinal direction unless stated)
  3. Testing performed on each melt of material per heat treatment batch
  4. ASTM G48A corrosion test (at 50°C)  no pitting and < 0.8g/m2 weight loss
  5. Ferrite content   35-55%
  6. Microstructure certified free from grain boundary carbides, sigma, chi and laves phases
  7. Specification only applicable for nominal critical wall thickness ≤1” (25.4mm) after conversion of bar to tubular form

 

 

 

Physical Properties:

Density (Kg/m3) 7810
Magnetic Permeability (20°C) 33
Young’s Modulus (kN/mm2) 220
Specific Electrical Resistance, 20°C (Ω-m) 0.80 x 10-6
Mean coefficient of thermal expansion, 20-100°C (m/m/degC) 11.1 x 10-6
Specific Heat, 20°C (J/kg.K) 475
Thermal conductivity, 20°C (W/m.K) 14.2
Fracture Toughness, KQ (MPa/m2) 98

Downloads

Datasheet - SD-Ferralium 255 SD50 HS110

Datasheet - SD-Ferralium 255 SD50 HS110

Brochure - Ferralium 255-SD50 - detailed product information (rev2)

Brochure - Ferralium 255-SD50 - detailed product information (rev2)

Brochure - Ferralium 255-SD50 - Machining Guidelines

Brochure - Ferralium 255-SD50 - Machining Guidelines

Brochure - Ferralium 255-SD50 - Welding Guidelines

Brochure - Ferralium 255-SD50 - Welding Guidelines

Brochure - Ferralium 255, The reliable alloy choice for acid production processes

Brochure - Ferralium 255, The reliable alloy choice for acid production processes