09429 The Corrosion Potential of Welded and Thermally Aged Alloy 22 in Aerated Aqueous Solutions

Available for download

Product Number: 51300-09429-SG

ISBN: 09429 2009 CP

Author: Ricardo M. Carranza, Raul B. Rebak and Martin A. Rodriguez

Publication Date: 2009

Member Price: $0.00

Non Member Price: $20.00

Price: $20.00

Qty:

Alloy 22 (N06022) is a nickel base alloy highly resistant to all forms of corrosion. In aggressive environmental conditions Alloy 22 could suffer localized attack such as crevice corrosion. For a given application, the occurrence of localized corrosion is governed by the values of the critical potential (Ecrit) for crevice corrosion and the corrosion potential (Ecorr). If by natural evolution Ecorr may reach potential values in the order of Ecrit, localized corrosion may be expected. The objective of this work was to study the metallurgical effect of Alloy 22 on the corrosion potential in a variety of electrolyte solutions. The Ecorr of Alloy 22 was monitored as a function of time for non-welded (or mill annealed – MA), as-welded (ASW), and as-welded plus high temperature aged (HTA) rods. The six different electrolyte solutions studied included acidic and alkaline, reducing and oxidizing, detrimental and nondetrimental for crevice corrosion. In general the HTA rod established the highest Ecorr followed by the ASW and the MA rods. The higher Ecorr of the HTA materials was attributed to the presence of second phase topologically close packed (TCP) particles. This hypothesis needs to be confirmed by further testing.

Keywords: N06022, corrosion potential, mill annealed, as-welded, high temperature aged