N10276, W. Nr. 2.4819, SMC276, Hastelloy C276
Alloy Group
Solid Solution Nickel Alloy
Corrosion Resistance
Severe
Yield Strength
110
—
160
Wall Tolerance
0.875
Density
0.323
PREN
75.55
—
89.1
C276 (UNS N10276) is a cold-hardened nickel-based alloy designed to perform under the most demanding well conditions, with a temperature tolerance up to 450°F.
Not only does C276 offer exceptional corrosion resistance in the harshest environments, but it also achieves higher strengths compared to other nickel alloys. As a result, it is widely used for downhole tubular components, packers, and other subsurface equipment in high-pressure, high-temperature (HPHT) wells, Saltwater Injection wells, and Acid Gas Injection (AGI) wells. However, it is important to carefully assess all environmental factors, including H2S, CO2, temperature, pH, and chloride concentration, before finalizing material selection.
This alloy is classified as a type 4e alloy in MR0175/ISO15156, with no restrictions on H2S partial pressure below 400°F and is resistant to 1000 psi H2S at 450°F.
Nickel-base alloys are primarily employed in environments where the partial pressure of H2S exceeds 3 psi. These alloys are enhanced with increased levels of Nickel, Molybdenum, and other elements to extend their performance in harsh conditions involving high temperatures, H2S, and chlorides. Nickel alloys are approved for highly sour environments in accordance with NACE MR0175/ISO 15156. In the annealed condition yield strengths may range from 30 to 55 ksi. Pipe is typically supplied in the cold-hardened condition with yield strength between 110 and 160 ksi.
| Tensile Strength | Yield Strength | Elongation |
| minimum, ksi | minimum, ksi | minimum, % |
| 100 | 41 | 40 |
* Higher strength properties can be provided in the cold hardened condition.
