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HAYNES® Alloys

Resistance to Pitting and Crevice Corrosion

ULTIMET® alloy exhibits very high resistance to chloride-induced pitting and crevice attack, forms of corrosion to which the austenitic stainless steels are particularly prone.

To assess the pitting resistance of ULTIMET® alloy relative to other corrosion-resistant materials, it has been subjected to tests in Green Death (11.5% H2SO4 + 1.2% HCl + 1% FeCl3 + 1% CuCl2). Experiments wereperformed at various temperatures (in increments of 5°C) to determine the lowest temperature at which pitting occurs in a 24 h test period (the so-called Critical Pitting Temperature for Green Death). The results were as follows:

Alloy Critical Pitting Temperature
- °F °C
ULTIMET® 248 120
C-22® 248 120
C-276 230 110
625 167 75
6B 113 45
316L 77 25
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