Sandvik SAF 3207 HD™ – Premium Hyper‑Duplex Stainless Steel for Deepwater & Corrosive Environments
Sandvik SAF 3207 HD™ is a hyper-duplex (austenitic-ferritic) stainless steel for service in highly corrosive conditions where also high mechanical strength is necessary. This makes the grade ideal for applications such as deepwater umbilicals. Sandvik SAF 3207 HD™ is characterized by:
More technical information and charts that are relevant to the materials corrosion, mechanical and physical performance are displayed in the figures on the right side of the material page.
Datasheet URL:
Sandvik SAF 3207 HD™
Datasheet updated 2019-12-20 10:08 (supersedes all previous editions)
Properties
General
| Property | Temperature | Value | Comment |
|---|---|---|---|
Density | 23.0 °C | 7.7 g/cm³ | |
Recycled Content | 82.1 % | Average recycled content |
Mechanical
| Property | Temperature | Value | Comment |
|---|---|---|---|
Elastic modulus | 20.0 °C | 200 GPa | |
Elongation | 23.0 °C | 25 % | min. |
Elongation A2 | 23.0 °C | 15 % | min. |
Hardness, Rockwell C | 23.0 °C | 36 [-] | max. |
Tensile strength | 20.0 °C | 850 - 950 MPa | depending on the wall thickness |
50.0 °C | 923 MPa | depending on the wall thickness | |
100.0 °C | 850 MPa | depending on the wall thickness | |
150.0 °C | 811 MPa | depending on the wall thickness | |
200.0 °C | 784 MPa | depending on the wall thickness | |
250.0 °C | 785 MPa | depending on the wall thickness | |
300.0 °C | 791 MPa | depending on the wall thickness | |
Yield strength Rp0.2 | 20.0 °C | 700 - 770 MPa | min. depending on the wall thickness |
100.0 °C | 657 MPa | min. depending on the wall thickness | |
150.0 °C | 609 MPa | min. depending on the wall thickness | |
200.0 °C | 585 MPa | min. depending on the wall thickness | |
250.0 °C | 582 MPa | min. depending on the wall thickness | |
300.0 °C | 572 MPa | min. depending on the wall thickness | |
Thermal
| Property | Temperature | Value | Comment |
|---|---|---|---|
Coefficient of thermal expansion | 100.0 °C | 1.35E-5 1/K | for 30°C to the mentioned temperature |
200.0 °C | 1.35E-5 1/K | for 30°C to the mentioned temperature | |
300.0 °C | 1.4E-5 1/K | for 30°C to the mentioned temperature | |
400.0 °C | 1.45E-5 1/K | for 30°C to the mentioned temperature | |
Specific heat capacity | 20.0 °C | 480 J/(kg·K) | |
100.0 °C | 510 J/(kg·K) | ||
200.0 °C | 540 J/(kg·K) | ||
300.0 °C | 570 J/(kg·K) | ||
400.0 °C | 590 J/(kg·K) | ||
Thermal conductivity | 20.0 °C | 13 W/(m·K) | |
100.0 °C | 15 W/(m·K) | ||
200.0 °C | 16 W/(m·K) | ||
300.0 °C | 18 W/(m·K) | ||
400.0 °C | 20 W/(m·K) | ||
Electrical
| Property | Temperature | Value |
|---|---|---|
Electrical resistivity | 23.0 °C | 8.7E-7 Ω·m |
Chemical properties
| Property | Value | Comment | |
|---|---|---|---|
Carbon | 0.03 % | max. | |
Chromium | 32 % | ||
Iron | Balance | ||
Manganese | 1.5 % | max. | |
Molybdenum | 3.5 % | ||
Nickel | 7 % | ||
Nitrogen | 0.5 % | ||
Phosphorus | 0.04 % | max. | |
Silicon | 0.8 % | max. | |
Sulfur | 0.01 % | max. | |
Technological properties
| Property | ||
|---|---|---|
| Application areas | Sandvik SAF 3207 HD™ hyper-duplex steel has been developed for deepwater umbilicals, an application with extreme requirements on pitting and crevice corrosion resistance, mechanical strength and fatigue properties. Offering greater yield strength, greater corrosion resistance and superior fatigue properties compared with super-duplex steels, Sandvik SAF 3207 HD™ hyper-duplex steel is also an excellent material choice for a range of other oil and gas applications. For example, when resistance to hydrogen sulfide (H₂S) is a requirement, such as in raw seawater injection, control lines and chemical injection lines, Sandvik SAF 3207 HD™ offers high reliability and operational safety leading to lower operating costs. | |
| Corrosion properties | General corrosion: Sandvik SAF 3207 HD™ is highly resistant to corrosion by organic acids, e.g. formic acid and acetic acid, see Figure 4. Resistance to inorganic acids is comparable to, or even better than that of high alloy austenitic stainless steels in certain concentration ranges. Figures 5 and 6 show isocorrosion diagrams for sulfuric acid and hydrochloric acid, respectively. Pitting and crevice corrosion: The pitting and crevice corrosion resistance of stainless steel is primarily determined by the content of chromium, molybdenum and nitrogen. The manufacturing and fabrication practice, e.g. welding, are also of vital importance for the actual performance in service. A parameter for comparing the resistance to pitting in chloride environments is the PRE number (Pitting Resistance Equivalent). The PRE is defined as, in weight-% PRE = %Cr + 3.3 x %Mo + 16 x %N The minimum PRE-value for Sandvik SAF 3207 HD is 50.One of the most severe pitting corrosion tests, applied to stainless steels, is ASTM G48 i.e. exposure to 6% FeCl₃. In a modified version of the ASTM G48A test, the sample is exposed for periods of 24 hours. When pits are detected, together with a substantial weight loss (> 5 mg), the test is interrupted. Otherwise, the temperature is increased by 5°C (9°F) and the test continued with the same sample. The crevice corrosion test was performed in 6% FeCl₃, with a crevice specified in the MTI-2 procedure, where an artificial crevice is mounted on the sample with a torque of 0.28 Nm. The values obtained and comparisons with Sandvik SAF 2507® are given in Figure 7. Sandvik SAF 3207 HD™ performs better than Sandvik SAF 2507®. | |
| Heat Treatment | The tubes are normally delivered in heat treated condition. If additional heat treatment is needed due to further processing the following is recommended. Solution annealing: 1040-1140°C (1905-2085°F), rapid cooling in air, protective atmosphere or water. | |
| Machining | Being a dual phase material (austenitic-ferritic), Sandvik SAF 3207 HD™ will present a different tool wear profile from that of austenitic stainless steels. The cutting data (speed and feed) must, therefore, be lower than that recommended for austenitic grades. | |
| Other | Forms of supply: Seamless tubes in Sandvik SAF 3207 HD™ can be supplied in typical umbilical tube dimensions. The delivery condition is either solution annealed and either white pickled or polished. | |
| Welding | The weldability of Sandvik SAF 3207 HD™ is good. Welding must be carried out without preheating and subsequent heat treatment is normally not necessary. A suitable method of fusion welding is gas tungsten arc welding GTAW/TIG with shielding gas of Ar+2% N₂. For tube to tubesheet welding, it is recommended to use Ar+3% N₂ as shielding gas to have proper weld metal structure. For Sandvik SAF 3207 HD™, heat input of 0.2-1.0 kJ/mm and interpass temperature of <100°C (210°F) are recommended. Recommended filler metals: | |
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