Given the specialized nature of SP0170, it is often confused with other NACE standards. The table below helps clarify the distinctions:
Identify all equipment constructed from 300-series stainless steels or austenitic nickel alloys operating within the sensitization temperature range in sulfur-rich environments.
Engineers looking up historical or current iterations should note the systemic changes in how corrosion standards are cataloged. Historically published by NACE International, these guidelines underwent a major organizational shift when NACE merged with the to form AMPP . nace sp0170 pdf 2021
The Accuris Standards Store provides official copies of NACE SP0170-2018, which outlines specific mitigation procedures to prevent the chemical reactions that trigger PTA-SCC:
This is a common field procedure where internal surfaces are washed with an alkaline solution to neutralize any acids that might form. The standard notes that field experience has demonstrated austenitic stainless steels are effectively protected when alkaline wash solutions are properly applied to all wetted surfaces. Given the specialized nature of SP0170, it is
When these alloys are exposed to temperatures between 425°C and 815°C (797°F to 1500°F)—either during high-temperature refinery operations or welding—chromium carbides precipitate along the grain boundaries. This depletes the adjacent areas of chromium, leaving the grain boundaries highly susceptible to localized corrosive attack by polythionic acids.
Dehumidified air is continuously pumped through the equipment. When these alloys are exposed to temperatures between
NACE SP0170 is a copyrighted document published by AMPP (The Association for Materials Protection and Performance, formed by the merger of NACE International and SSPC). While this article provides an expert overview, you must purchase the official NACE SP0170 PDF 2021 from the AMPP website or authorized distributors for legal engineering use.
As of 2021, NACE International merged with SSPC to form AMPP. The standard is available for purchase and download through: (formerly NACE Store) ANSI Webstore GlobalSpec/Accuris