Corrosion Performance
HASTELLOY® G-35® alloy* was designed to resist “wet process” phosphoric acid, which is widely used in the production of fertilizers. Tests indicate that it is far superior to HASTELLOY® G-30® alloy and stainless steels, in this chemical. It was also designed to resist localized attack in the presence of chlorides, since under-deposit attack is a potential problem in evaporators used to concentrate “wet process” phosphoric acid.
As a result of its high-chromium content, G-35 alloy is extremely resistant to other oxidizing acids, such as nitric, and mixtures containing nitric acid. It possesses moderate resistance to reducing acids, as a result of its appreciable molybdenum content, and, unlike other nickel-chromium-molybdenum alloys, it is very resistant to “caustic dealloying” in hot sodium hydroxide.
Finally, G-35 alloy is much less susceptible to chloride-induced stress corrosion cracking than the high-chromium stainless steels and nickel-chromium-iron alloys traditionally used in “wet process” phosphoric acid.
Product Forms
G-35 alloy is available in the form of plate, sheet, strip, billet, bar, wire, covered electrodes, pipe, and tubing.
Potential Applications
· “Wet process” phosphoric acid evaporators.
· Pickling in nitric and hydrofluoric acids.
· Chemical process industry systems involving nitric and chlorides.
· Caustic neutralizing systems.
· Systems requiring resistance to high temperature corrosion at 800-1200°F.
Field Test Program
Samples of G-35 alloy are available for field trials. Furthermore, samples can be weighed prior to delivery, and then reweighed after test by the customer and reports provided on corrosion rates and other observations. For samples, please contact one of the Haynes International Service Centers listed on the back of this brochure.
Specifications
G-35 alloy is covered by ASME, ASTM, and DIN specifications. A listing of these is provided on page 14. |
