SAF™ 2507 for OCTG Tube and pipe, seamless

• UNS: S32750
• EN Number: 1.4410
• EN Name: X 2 CrNiMoN 25-7-4
• SS: 2328

Product standards

Seamless tubes used as casing, tubing and coupling stock:

• ISO 13680, PSL-1 and PSL-2
• API spec 5CRA, PSL-1 and PSL-2

Approvals

• NACE MR0175/ISO 15156 (Petroleum and natural gas industries - Materials for use in H2S-containing Environments in oil and gas production - Part 3: Cracking-resistant CRAs (corrosion resistant alloys and other alloys) (Published:2015)
• SAF 2507 grade 80 ksi, 90 ksi, 110 ksi, and 125 ksi, (PSL-1 or PSL-2) and grade 140 ksi (PSL-1) can be delivered with API-5CRA Monogram (License Number 5CRA-0016)

Chemical composition (nominal)

Chemical composition (nominal) %

C	Si	Mn	P	S	Cr	Ni	Mo	N
≤0.03	≤0.8	≤1.2	≤0.025	≤0.015	25	7	4	0.3

Applications

SAF^™ 2507 is used for high strength downhole production tubing, casing, and liners in sour gas wells. This includes environments with high temperatures, high partial pressures of CO₂ and H₂S, and high chloride concentrations. The material is suitable for use in production tubing and flowlines for the extraction of oil and gas from sour wells, in refineries and in process solutions contaminated with chlorides.

The high strength of SAF^™ 2507 makes the material an attractive alternative to the austenitic steels in structures subjected to heavy loads.

Corrosion resistance

Pitting Corrosion

SAF™ 2507 can withstand high temperatures in aggressive environments without pitting. A recognized method of ranking a material's susceptibility to localized corrosion is by means of the PRE number (Pitting Resistance Equivalent). This PRE number is based on the contents of chromium, molybdenum and nitrogen in the alloy according to the following formula:

PRE = %Cr + 3.3 × %Mo + 16 × %N

A PRE number is the relative measure of a material's ability to resist pitting corrosion in chloride containing environments. The PRE number for SAF™ 2507 is compared with other materials in the following table:

SAF™ 2507 has a minimum PRE number of 42.5, which confirms its high resistance to pitting corrosion when chlorides are present.

Stress Corrosion Cracking (SCC)

SAF™ 2507 has excellent resistance to chloride induced stress corrosion cracking (SCC). The SCC resistance of SAF™ 2507 in chloride solutions at high temperatures is illustrated in Figure 13. There were no signs of SCC up to 1000 ppm Cl-/300°C and 10000 ppm Cl-/250°C. SAF™ 2507 U-bend specimens exposed for 1000 hours in hot brine (108°C, 226°F, 25% NaCl) showed no cracking.

Figure 13. SCC resistance in oxygen-bearing (abt. 8 ppm) neutral chloride solutions. Testing time 1000 hours. Applied stress equal to proof strength at testing temperature.

Fabrication

SAF™ 2507 tubes are supplied in the cold worked condition and are intended for use with threaded connections.

Forms of supply

Materials for oil and gas production

For production tubing, casing, liner, and coupling stock for downhole oil and gas applications, SAF™ 2507 is supplied solution annealed (80 ksi, 90 ksi) or cold hardened with high strength properties (110 ksi, 125 ksi, 140 ksi).

Full details on sizes, finishes and mechanical properties are available on request. Email: stog.smt@alleima.com

Mechanical properties

At 20°C (68°F)

Metric and imperial units

1 MPa = 1 N/mm²
a) R_p0.2 corresponds to 0.2% offset yield strength.

At high temperatures

SAF^TM 2507 shows very good mechanical properties at higher temperatures. Further information is available on request. Email: stmo.smt@alleima.com

Metric units / Imperial units

Physical properties

Density, at 7.8 g/cm³, 0.28 lb/in³

Thermal conductivity

Metric units

Imperial Units

Specific Heat Capacity

Metric units

Imperial Units

Thermal Expansion

Metric units, x10^-6/°C

Imperial units, x10^-6/°F

Resistivity

Metric units

Imperial units

Modulus of elasticity

Metric units, x10³

Imperial units, x10³

Impact Strength

SAF™ 2507 possesses good impact strength. The ductile brittle transition temperature is below -50°C (-58°F).

Figure 2. Typical impact energy curve for SAF™ 2507 using Charpy V specimens (average of 3 at each temp.). Parent metal samples taken in the longitudinal direction from 260 x 12mm hot extruded and solution annealed (1075°C / 1965°F) tube.