ISO 23865:2021

Overview

ISO 23865:2021 - Non-destructive testing - Ultrasonic testing - General use of full matrix capture/total focusing technique (FMC/TFM) and related technologies - provides general provisions and good-practice guidance for applying array-based ultrasonic inspection using FMC/TFM. The standard promotes consistent, repeatable ultrasonic testing (UT) workflows for manufacturing, in-service inspection and repairs. It focuses on imaging, characterization and sizing of discontinuities in homogeneous, isotropic materials (e.g., low-alloy carbon steels and common aerospace aluminium and titanium alloys) and gives recommendations for other materials (for example, austenitic steels). ISO 23865:2021 does not define acceptance levels for discontinuities; weld-specific guidance is covered in ISO 23864.

Key Technical Topics and Requirements

ISO 23865:2021 addresses the full lifecycle of FMC/TFM inspection and related technologies, including:

• Principle and comparison: explanation of FMC/TFM vs conventional phased array (PAUT), and when to use total focusing technique for superior image resolution.
• Surface condition and couplant: requirements to ensure reliable acoustic coupling and repeatable results.
• Information before testing: data needed to plan procedures (material, geometry, expected defects).
• Personnel: competency and qualification expectations aligned with ISO 9712 for NDT personnel.
• Equipment and probes: instrument, probe and scanning mechanism requirements; sampling frequency and probe characteristics.
• Data acquisition & processing: FMC capture, TFM imaging, post-processing, sensitivity correction and grid verification.
• Preparation & verification: system checks, sensitivity setting, ROI/grid verification, and recommended test parameters.
• Evaluation & reporting: interpretation of TFM images, assessment of image quality, identification/characterization of indications, data storage and test report content.

Practical Applications and Users

ISO 23865:2021 is intended for professionals implementing advanced ultrasonic imaging and inspection programs:

• NDT engineers and inspection technicians applying FMC/TFM for high-resolution imaging.
• Manufacturers and quality teams using ultrasonic array inspection during production.
• Asset owners and service providers performing in-service inspection, damage assessment, characterization and sizing.
• NDT training and certification bodies referencing best practices for array-based UT.

Benefits include improved defect detectability and sizing accuracy through full matrix capture and total focusing processing, making FMC/TFM well suited for complex geometries and critical aerospace, petroleum, power and transport components.

Related Standards

Key normative and related references mentioned in ISO 23865:2021:

• ISO 5577 (UT vocabulary)
• ISO 9712 (NDT personnel qualification)
• ISO 16810 (UT general principles)
• ISO 18563‑1 / ‑2 (characterization and verification of phased array equipment)
• ISO 23243 (UT with arrays - vocabulary)
• ISO 23864 (FMC/TFM application to weld testing)

Keywords: ISO 23865:2021, FMC/TFM, full matrix capture, total focusing technique, ultrasonic testing, NDT, phased array, inspection, characterization, sizing.