Overview - ISO 17245:2015 (High temperature corrosion testing by immersion)
ISO 17245:2015 specifies a standardized test method for high temperature corrosion testing of metallic materials by immersing specimens in molten salt or other corrosive liquids under static conditions. The method evaluates corrosion resistance while exposing test pieces to controlled high temperature in a defined gas environment. Two gas-environment options are covered: (a) a stagnant inert gas and (b) a flowing reactive gas. ISO 17245:2015 excludes tests where specimens are embedded in corrosive powders or have applied surface deposits (see related standards).
Key topics and technical requirements
- Test principle: Immersion of metallic test pieces in a homogeneous corrosive liquid at elevated temperature with controlled atmosphere; at least three specimens per condition for reproducibility.
- Specimen preparation: Rectangular plate, disc or cylinder; specified minimum dimensions (document: minimum surface area 300 mm and minimum thickness 1.5 mm). Final surface finish using abrasives (≈15 µm mean particle diameter) and removal of affected machining layers.
- Environment control:
- Stagnant inert gas: Chamber purged and closed; overpressure valve recommended.
- Flowing reactive gas: Constant flow rate, optional humidification with deionized water, gas flow monitoring and dew‑point control to avoid condensation.
- Apparatus: Closed furnace/test chamber with crucible, thermocouple temperature monitoring, gas inlet/outlet and temperature-regulating heating unit.
- Measurements and post-test analysis:
- Mass change determination (descaling procedures before final mass measurement).
- Dimensional changes and microstructure/surface examination.
- Pre-test weighing precision and dimensional measurement tolerances specified (e.g., dimensional measurement precision ±0.02 mm; repeat mass-measurement consistency better than 0.05 mg).
- Safety and materials: Guidance to prepare corrosive substances from reagent-grade chemicals or field deposits and to follow safety precautions for hazardous molten salts/ashes.
Applications and users
ISO 17245:2015 is practical for:
- Corrosion engineers and materials scientists performing molten salt corrosion testing and high-temperature liquid immersion tests.
- Test laboratories doing material screening, quality control, and R&D for alloys used in high‑temperature corrosive environments.
- Industries such as power generation (boilers, waste‑to‑energy), chemical processing, metallurgy and thermal power components where components contact molten salts or corrosive liquids.
The standard helps select alloys, compare corrosion resistance, and produce reproducible data for material specification and failure analysis.
Related standards
- ISO 17248 - exposure in compacted corrosive powders
- ISO 17224 - tests with applied surface deposits (salt/ash)
- ISO 21608 - high‑temperature oxidation testing in gaseous environments
- ISO 8044, ISO 8407, ISO 26146 - terminology, descaling and metallography references
Keywords: ISO 17245:2015, high temperature corrosion testing, molten salt, immersion testing, corrosive liquid, static conditions, corrosion resistance, test method.