Nace | Sp0170 Pdf
Continuous purging with air that has a dew point below -45°C (-50°F).
Maintaining the environment above the water dew point to prevent liquid water formation.
Corrosion waits for no one. A refinery shutdown is a vulnerable time for austenitic stainless steel equipment. Without the guidance found in , you risk irreversible Stress Corrosion Cracking that could lead to costly repairs or, worse, safety hazards.
The most reliable way to obtain the correct and most current version is through NACE/AMPP's authorized distribution network. Several online standards retailers, such as Accuris (formerly Techstreet), ANSI Webstore, and GlobalSpec, are official partners. nace sp0170 pdf
The committee wanted examples, not only procedures. The submission went through iterations — peer reviews, redlines, footnotes. Some resisted, arguing standards must be conservative and rigid. Others saw the same pattern Maya had: standards worked best when complemented by informed judgment.
When standard austenitic stainless steels (like 304 or 316) are exposed to temperatures between 425°C and 815°C (800°F to 1500°F), chromium carbides precipitate along the grain boundaries. This leaves the adjacent zones depleted of chromium—a process called sensitization .
). NACE SP0170 outlines the exact chemical and operational safeguards required to shield sensitized alloys from this acid network. Continuous purging with air that has a dew
When austenitic stainless steels (such as 304, 304H, 316, or 316H) are exposed to temperatures between 425°C and 815°C (800°F to 1500°F) during operation, chromium carbides precipitate along the grain boundaries. This process, known as sensitization , leaves the zones immediately adjacent to the grain boundaries depleted of chromium, dropping below the 12% threshold required for passivation.
What is Polythionic Acid Stress Corrosion Cracking (PTA-SCC)?
While NACE SP0170 focuses on operational shutdown procedures, it also references standard metallurgical practices that reduce the inherent risk of PTA-SCC from the design phase. A refinery shutdown is a vulnerable time for
Ensure that any water used for rinsing or chemical blending contains less than 50 ppm chlorides to prevent secondary cracking modes.
It was 11:47 PM. A single lamp illuminated her desk, casting long shadows over the 48-page document. She’d been staring at Paragraph 5.3.4 for two hours.
