Aqueous Solutions Corrosion Resistance Ladder – Stainless Steels and Nickel Alloys

Published: July 25, 2018 By: Paul Cripps

A ranking of the relative corrosion resistances of stainless steels, specialty stainless steels and nickel alloys is provided. The ranking of each stainless steel or alloy is made by calculating their individual PREN values. The PREN formula is from NACE MR0175/ISO 15156 sour service standard. The PREN is a relative ranking of the stainless steel or alloy to its resistance to pitting corrosion in aqueous solutions with chlorides and oxygen. For example, for those steels and alloys with PREN of 40 or higher, they are corrosion resistant to seawater.

Note although this ladder is a convenient means of comparing corrosion resistance of various stainless steel and nickel alloys, the ranking is GENERAL, please review specific corrosion data for each steel or alloy to determine their exact corrosion rates in the fluid(s) considered. For example, most of the “superalloys” in the ladder have specific “Achilles Heels”: solutions that will aggressively corrode them.

The content provided in this white paper is intended solely for general information purposes, and is provided with the understanding that the authors and publishers are not herein engaged in rendering engineering or other professional advice or services.  Any use of this information should be done only in consultation with a qualified and licensed professional. The information in this white paper was posted with reasonable care and attention.  However, it is possible that some information in this white paper is incomplete, incorrect, or inapplicable to particular circumstances or conditions. Ammonite does not accept liability for direct or indirect losses resulting from using, relying or acting upon information in this white paper.