ISO 22825:2017

Overview - ISO 22825:2017 (Ultrasonic testing of austenitic and nickel‑based welds)

ISO 22825:2017 provides a structured approach for developing and implementing ultrasonic testing (UT) procedures specific to welds in austenitic steels, stainless steels, nickel‑based alloys, duplex steels and dissimilar metal welds. It addresses the special challenges of testing coarse‑grained, anisotropic weld metals where beam distortion, mode conversion and limited penetration can occur. The standard applies to both manual and mechanized UT and covers testing for manufacturing quality assessment and detection of service‑induced discontinuities. Note: ISO 22825 does not define acceptance levels - these are applied separately according to the testing scope.

Key topics and technical requirements

• Scope and objectives: Guidance for procedure development for austenitic and nickel‑based welds (Clause 1, Introduction).
• Pre‑test information: Material, purpose, testing extent, reference blocks, acceptance criteria, surface condition and temperature (Clause 4).
• Personnel: Operators must be qualified in accordance with ISO 9712 and trained on representative austenitic/duplex samples and dual‑element probes (Clause 5).
• Test equipment: Requirements and verification per EN 12668‑1/2/3 for conventional UT; phased‑array permitted when compliant with ISO 18563‑1/2/3. Focal curves and appropriate reference blocks are required; dual‑element compression wave probes have specific verification allowances (Clause 6).
• Range and sensitivity setting: Use of calibration and reference blocks (Clauses 7–8); use of side‑drilled holes and other reflectors for calibration.
• Test procedure development: Detailed content and practical optimization steps, selection of ultrasonic techniques (dual‑element, refracted compression waves, creeping waves, phased array) and scanning strategies (Clause 9).
• Evaluation and reporting: Indication classification, sizing, scanning practice, parent metal testing, and comprehensive test reporting (Clauses 10–12).
• Informative annexes: Angle‑beam techniques, stainless steel calibration blocks and reference blocks are provided to aid implementation.

Practical applications - who uses this standard

• NDT engineers and technicians developing UT procedures for austenitic and nickel‑based welds
• Welding quality assurance teams in nuclear, petrochemical, power generation and pressure‑containing industries
• NDT training providers and certifying bodies referencing ISO 9712 for personnel qualification
• Manufacturers and inspection contractors performing manual or mechanized ultrasonic weld inspection

Related standards

• ISO 9712 (NDT personnel qualification)
• EN 12668‑1/2/3 (UT equipment and probes)
• ISO 18563‑1/2/3 (phased‑array UT)
• ISO 17635, ISO 5577, ISO 7963

Keywords: ISO 22825:2017, ultrasonic testing, austenitic steels, nickel‑based alloys, non‑destructive testing, weld inspection, dual‑element probe, phased array, calibration blocks, NDT procedures.