Overview
ISO 11463:2020 - Corrosion of metals and alloys - Guidelines for the evaluation of pitting corrosion provides practical guidance for selecting procedures to identify, examine and evaluate corrosion pits and pit growth rate. The standard covers visual and microscopic examination, in situ non‑destructive inspection (NDT) and ex‑situ surface analysis methods to quantify pit size, shape, depth and extent. It is intended to support assessment of remaining life, material selection and failure analysis where pitting corrosion is a concern.
Key topics
- Identification and examination of pits
- Preliminary low‑magnification visual inspection (photography recommended).
- Optical microscopy (approximately ×20) to assess pit size, distribution and shape.
- Use of grids (3–6 mm squares) or x–y stages for pit counting and spatial mapping.
- In situ non‑destructive inspection
- Radiographic methods (note: pits need to be ≈0.5% of metal thickness to be detectable).
- Electromagnetic techniques (eddy‑current, magnetic particle inspection).
- Ultrasonics (contact and immersion methods; test from the non‑pitted face).
- Liquid penetrants and replication techniques for field inspection.
- Ex‑situ examination and characterization
- Scanning electron microscopy (SEM), X‑ray computed tomography (X‑CT).
- Optical 3D techniques (confocal laser scanning, infinite focus microscopy).
- Image analysis and profilometry for quantitative surface profiling and pit depth.
- Extent and evaluation of pitting
- Mass loss, pit depth measurement methods (metallography, machining, micrometer/depth gauge, microscopy).
- Use of standard charts, metal penetration metrics and statistical approaches to quantify pitting severity.
- Reporting
- Requirements for test reports and preservation of corrosion products for further analysis.
- Additional guidance for cleaning (ISO 8407 referenced) and preparing metallographic specimens.
Applications and who should use it
ISO 11463:2020 is useful for:
- Corrosion engineers and materials scientists assessing service damage or residual life.
- Failure analysts conducting root‑cause investigations where pits may initiate cracking or fatigue.
- NDT technicians and inspectors in oil & gas, marine, chemical processing, power generation and infrastructure.
- Laboratories performing material screening, qualification tests or research on pitting resistance.
- Asset owners and coating specialists evaluating protective systems and maintenance strategies.
Practical outcomes include standardized pit measurement, improved comparability of test results, better decision‑making for repairs/replacements, and guidance on selecting appropriate NDT and surface analysis tools.
Related standards
- ISO 8407 - Cleaning of corrosion products from corrosion test specimens (referenced for chemical cleaning).
- Produced by ISO/TC 156 (Corrosion of metals and alloys).
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