Nace Sp0170 Pdf 2021 [LEGIT × 2025]
When this acid forms on a sensitized material—one where chromium carbides have precipitated at grain boundaries due to prior high-temperature exposure—it attacks the chromium-depleted zones along the grain boundaries. This leads to rapid intergranular cracking without significant metal loss. The consequences can be catastrophic, including the failure of critical components like reactor shells, catalyst transfer lines, furnace components, valves, and instrumentation.
The chemical hazard activates when three distinct conditions converge during a refinery shutdown: nace sp0170 pdf 2021
