Ensure the water used for flushing and solution preparation is ultra-low in chlorides to avoid exchanging one cracking mechanism for another.
AMPP — Ассоциация по защите и эксплуатационным характеристикам материалов .
The National Association of Corrosion Engineers (NACE) developed the SP0170 standard to provide a comprehensive framework for corrosion prevention in carbon steel pipelines. The standard outlines the requirements for coatings and cathodic protection (CP) systems, which are essential for mitigating corrosion and ensuring the safe and reliable operation of pipelines. nace sp0170 pdf 2021
Austenitic stainless steels (such as 304, 304L, 316, 321) become sensitized when exposed to elevated temperatures ( 425∘C425 raised to the composed with power C 815∘C815 raised to the composed with power C
The standard provides a clear roadmap to break the chemical loop required for PTA SCC. Refineries typically deploy one or more of the following three core mitigation procedures during a turnaround: 1. Dry Nitrogen Purging (Excluding Oxygen) Ensure the water used for flushing and solution
. This cracking typically occurs during refinery equipment shutdowns when sulfide corrosion products react with oxygen and water to form polythionic acids.
This polythionic acid is highly corrosive, specifically to the grain boundaries of susceptible alloys. The standard outlines the requirements for coatings and
To appreciate the 2021 update, we must revisit history. In the 1970s, catastrophic failures in sour oil fields led to the creation of NACE MR0175 ("Sulfide Stress Cracking Resistant Metallic Materials for Oilfield Equipment"). For decades, this standard was the "golden rule" for any metal touching wet H₂S.
The is a critical framework used in petroleum refineries to protect austenitic stainless steels from polythionic acid stress corrosion cracking (PTA SCC) during equipment shutdowns.
Beyond the primary methods, NACE SP0170 addresses other critical aspects of a shutdown strategy:
: The moment the equipment is opened for maintenance, oxygen and moisture rush in. They react with the iron sulfide scale to form Polythionic Acids ( H2SxO6cap H sub 2 cap S sub x cap O sub 6