CORROSION RESISTANCE OF HASTEllOY®AllOYS - Haynes ...

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SULFURIC ACID
HASTELLOY® alloy B-2 has outstanding resistance to pure sulfuric acid. Even
in the 70 to 80 percent acid concentration range, where other alloys have
significantly higher rates, alloy B-2 exhibits good resistance. It has a corrosion
rate of less than 5 mpy (0.13mm/yr) over a wide range of temperatures. Alloys
C-276 and C-22 have acceptable rates over a relatively extensive range of
concentrations and temperatures. HASTELLOY alloys G-3 and G-30 behave
similarly to alloys C-276 and C-22, but in dilute acid applications « 30
percent) the former alloys rates are slightly lower.
HAYNES alloy No. 25 is resistant to sulfuric acid in all concentrations at
room temperature. At 150 deg. F (66 deg. C) it can be used in concentrations up
to 60 percent. (See page No. 87.)
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Chloride contamination of sulfuric acid tends to increase the rate of attack
at all acid concentrations for HASTELLOY alloys B-2, and C-276, but has a
lesser effect on alloys G-30 and G-30.
ISOCORROSION DIAGRAM*
HASTELLOY® Alloy B-2
Resistance to Sulfuric Acid
400
Corrosion rates in parentheses are in mm/year.
I
I
Over 50 mpy
(Over 1.27)
200
LL
350
300