SAF2507 (Alloy 32750)

Description:

Sandvik SAF2507 is a super-duplex stainless steel for service in highly corrosive conditions, similar to Alloy 32750. As a super duplex stainless steel, the SAF 2507 combines the desirable aspects of both austenitic and ferritic grades. The higher chromium, molybdenum and nitrogen contents result in a Pitting Resistance Equivalent number (PREN) of >41, providing pitting and crevice corrosion resistance superior to austenitic and duplex stainless steels in almost all corrosive media, and a Critical Pitting Temperature exceeding 50°C.

Supplied in the annealed condition, the Sandvik SAF2507 achieves yield strengths of 80ksi (550Mpa), greater than most austenitic and duplex stainless steel grades. It cannot be hardened by heat treatment but can be strengthened by cold working. The Saf2507 also exhibits a low coefficient of thermal expansion and higher heat conductivity than austenitic steels and is suitable for working temperatures up to 300°C. Alloy 32750 is listed in NACE MR 0175 for sour service and having gained ASME Approval for Pressure Vessel applications it can be used in a wide variety of applications.

(Sandvik SAF2507 is a registered trademark of Sandvik Intellectual Property AB)

Key Features:

  • Excellent resistance to stress corrosion cracking (SCC) in chloride-bearing environments
  • Excellent resistance to pitting and crevice corrosion
  • High resistance to general corrosion
  • Very high mechanical strength
  • Physical properties that offer design advantages
  • High resistance to erosion corrosion and corrosion fatigue
  • Good weldability

Applications:

  • Oil and gas exploration and production - Chloride-containing environments such as seawater handling and process systems
  • Oil and Gas - refining, petrochemical and gas processing facilities where the process environment contains a high amount of chlorides, or is contaminated with hydrochloric acid
  • Marine - Mechanical components requiring high strength such as propeller shafts subject to high mechanical load in seawater and other chloride-containing environments
  • Chemical processing - Organic acid plants, also when process solutions are contaminated with e.g. chlorides
  • Pulp and paper production - Material for chloride-containing bleaching environments
  • Seawater cooling - Heat exchangers in refineries, chemical industries, process industries and other industries using seawater or chlorinated seawater as coolant
  • Salt evaporation - Evaporator units for production of corrosive salts, e.g. chlorides, sulfates and carbonates
  • Desalination plants - Pressure vessels for reverse osmosis units, tube and pipe for seawater transport, heat exchanger tubing
  • Geothermal wells - Heat exchangers in geothermal exploitation units, systems exposed to geothermal or high salinity brines

Chemical Composition:

Cr Ni Mo Co Nb (+Ta) Ti V W Cu C Mn N Si P S Fe Al
Min 24.50 6.00 3.00 0.50 0.24 0.10
Max 26.00 8.00 5.00 0.50 0.03 1.20 0.32 0.80 0.035 0.020 Bal

Mechanical Properties:

0.2% Proof Stress 550 N/mm2 79.8 ksi
Tensile Strength 800 N/mm2 116 ksi
Elongation, 5.65√S0 25%
Reduction of area 45%
Hardness (Brinell) <270
Impact Strength (Room Temp) 80J
Impact Strength (-46oC) Longitidinal 45J (35J min)
Transverse 45J (35J 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)
  3. Testing performed on each melt of material per heat treatment batch
  4. Hardness shall be in accordance with NACE MR 1075 with a maximum HRC of 25
  5. ASTM G48A corrosion test (at 50°C) No pitting and < 3.0g/m2 weight loss (ASTM specification < 4.0g/m2)
  6. Ferrite content 35-55%
  7. Microstructure certified free from grain boundary carbides, sigma, chi and laves phases

Physical Properties:

Density (Kg/m3) 7810
Magnetic Permeability (20°C) 33
Young’s Modulus (kN/mm2) 199
Specific Electrical Resistance, 20°C (µΩ.m) 0.8
Mean coefficient of thermal expansion, 20-300°C (m/m/oC) 11.1 x 10-6
Specific Heat, 20°C (J/kg.K) 475
Thermal conductivity, 20°C (W/m.K) 14.2

Downloads

SAF 2507 - product datasheet

SAF 2507 - product datasheet