Overview
ISO 19280:2017 - "Corrosion of metals and alloys - Measurement of critical crevice temperature for cylindrical crevice geometries in ferric chloride solution" - defines a laboratory test method to measure critical crevice temperature (CCT) for stainless steels and related alloys in oxidizing chloride environments. The standard addresses cylindrical crevice geometries (tube/rod) commonly found in heat exchangers, pipes, flanges and fasteners, and also applies to plate specimens. ISO 19280 uses chemical initiation in ferric chloride solution (not the electrochemical method of ISO 18070) to rank crevice corrosion resistance.
Key technical topics and requirements
- Test objective: Determine the minimum temperature at which crevice corrosion initiates (CCT), defined as a corroded depth ≥ 0.025 mm beneath the crevice former, ignoring edge attack.
- Test solutions: Uses oxidizing chloride media - typically 6 mass % ferric chloride or 6 mass % ferric chloride + 1 vol% HCl.
- Immersion procedure: Single-cell or multiple-cell immersion options; specimens are tested at increasing temperatures (typically in 5 °C increments) until CCT is observed after 24 h exposures.
- Apparatus and crevice former: A titanium frame (high corrosion resistance) with PTFE crevice formers and supporting decks is specified. A titanium bolt (thread M8 per ISO 4017) and washer apply controlled torque to induce the artificial crevice. Appropriate torque is important - when properly applied, CCTs for cylindrical specimens can match plate specimen results.
- Specimen considerations: Cylindrical (tube/rod or circular-arc) and flat plate geometries are covered; specimen size, surface finish and assembly details are defined in the standard.
- Acceptance criteria and reporting: Clear CCT criterion, inspection and evaluation steps, and required test-report content are specified.
Practical applications
ISO 19280 is used to:
- Rank and compare crevice corrosion resistance of stainless steels and high-alloy materials.
- Guide materials selection for components exposed to chloride/oxidizing environments - e.g., heat exchanger tubes, pipe supports, flanges, bolts and nuts.
- Support corrosion testing labs, quality control, failure analysis and materials qualification in industries such as nuclear, thermal power, desalination, oil & gas, and chemical processing.
Who should use this standard
- Corrosion engineers and materials scientists
- Test laboratories and certification bodies
- Manufacturers of tubular components and fasteners
- Design and maintenance engineers responsible for material selection in chloride-containing, oxidizing environments
Related standards
- ISO 18070 (electrochemical crevice initiation methods) - ISO 19280 uses chemical initiation instead
- ISO 8044 (corrosion terminology)
- ISO 4017 (bolt dimensions/threads referenced for torque application)
Keywords: ISO 19280, critical crevice temperature, CCT, crevice corrosion, ferric chloride, cylindrical crevice geometries, stainless steels, test method, crevice former.