COMMON TRADE NAMES: ICONEL® Alloy G3, Hastelloy® Alloy G-3
Alloy G3 (UNS N06985) is a cold hardened nickel-based alloy, intended for corrosion resistance to highly sour (H2S) environments with high chloride content, requiring high strength up to 400°F.
The high nickel and molybdenum content of G3 extends the sour service limits of nickel alloys while also providing excellent resistance to chlorides and dissolved oxygen. It is therefore used for downhole tubular components, packers, and other subsurface equipment in severely sour wells with high-pressure and high-temperature (HPHT) conditions, saltwater Injection wells, and Acid Gas Injection (AGI) wells. However, all environmental factors, including H2S, CO2 , temperature, pH, and chloride concentration, should be considered before final material selection.
For sour service applications, it is classified in MR0175/ISO15156 as a type 4d alloy, with no restrictions to a partial pressure of H2S below 300°F and resistant to 300 psi H2S at 425°F.
|≤ 0.015||21 - 23.5||BAL||18 - 21||≤ 1||≤ 1||6 - 8||≤ 5||1.5 - 2.5||≤ 0.04||≤ 0.03||≤ 0.5||≤ 1.5|
|Steel Making||Made by electric furnace process or blast furnace followed by Vacuum Oxygen Decarburization (VOD) process or Argon Oxygen Decarburization (AOD) Process|
|Pipe Making||Manufactured by traditional tube manufacturing processes, High strength tubulars should be furnished in cold worked condition|
|Heat Treatment||Solution Annealing Process before final cold drawing|
API 5CRA / ISO 13680 Group 4 Category 22-50-7
|NACE MR0175/ISO 15156
H2S Sour Service Limits
|No limit ≤ 300°F,
Refer to table for temperatures up to 450°F
|140||140||160||145||9||38||140 Grade not recommended for sour service|
|Elastic Modulus||psi x 106||28.9|
|Thermal Conductivity||Btu/ft h °F||5.8||6.8||8|
|Specific Heat||Btu/lb °F||0.11||0.11||0.11|