Hastelloy C-276 Selection

[ben]

Where exactly in oil & gas, and petrochemicals Hastelloy C-276 is selected when Inconel 625, Hastelloy C-22, or Inconel 825 can also be considered?

[arcpro]

Hastelloy C-276 is usually selected for a fairly specific reason: severe, mixed, localized corrosion environments where its broad resistance to oxidizing + reducing media and excellent resistance to pitting/crevice corrosion outweigh its higher cost.
C-276 is used in:
FGD absorber components
Scrubber internals
Spray headers
Mist eliminator supports
Wet gas ducts
Chloride-contaminated acidic condensate environments

The chemistry can simultaneously contain chlorides + sulfur species + acidic condensate + oxidizing species.
It is kind of over and above others especially for those conditions which are unsure to cause both oxidation and reducing corrosion.

[novice123]

What we know from Haynes International about C-276 is that early nickel-chromium-molybdenum alloys faced a major hurdle of welding them caused carbide precipitation in the heat-affected zones, severely stripping away their corrosion resistance. Equipment manufacturers were forced to perform complex, post-weld heat treatments.

In the 1960s, advancements in Argon-Oxygen Decarburization (AOD) refining allowed manufacturers to drop carbon and silicon levels to microscopic minimums. This breakthrough resulted in Hastelloy C-276, the first wrought nickel-chromium-molybdenum alloy that resisted grain-boundary precipitation during welding. It revolutionized fabrication and remains an industry benchmark for universal corrosion resistance.

[irish]

276 is good when you talk about welding due to low carbon content (<0.01%) it carries.
Carbide precipitation in grain boundaries /HAZ area would be lesser when compared to others like 625, 825 or C-22.
Excellent corrosion resistance therefore.