ISO 17635:2025

Overview

ISO 17635:2025 - Non-destructive testing of welds - General rules for metallic materials provides comprehensive guidance for selecting and applying non‑destructive testing (NDT) methods to welded metallic components. The standard helps organizations define testing scope and evaluate NDT results for quality control based on material, weld thickness, welding process, testing extent, and quality requirements. It specifies general rules, applicable standards, method selection, techniques and acceptance levels, and includes normative and informative annexes that correlate quality and testing levels.

Key technical topics and requirements

• Scope and limitations: Guidance on stages of manufacture, extent of testing and material limitations that affect NDT planning.
• Selection of testing methods: Criteria for choosing methods (visual, ultrasonic, radiographic, magnetic particle, liquid penetrant, etc.) tailored to butt/T‑joints, fillet welds and partial/full penetration joints.
• Updated ultrasonic techniques: Includes phased‑array ultrasonic (UT‑PA) for thin‑walled steel and total focusing method (UT‑TFM) - reflecting technological advances in ultrasonic NDT.
• Acceptance levels: Defines how acceptance levels for NDT relate to overall batch quality; they are not a direct one‑to‑one interpretation of ISO 5817 or ISO 10042 but are aligned on a general basis (moderate, intermediate, stringent).
• Documentation and testing plans: Requires written procedures, testing plans, individual test records and formal test reports to ensure traceability and reproducibility.
• Personnel and organization: Addresses personnel qualification, responsibilities of testing organizations and requirements for competent execution.
• Performance of testing: Specifies standards to apply, testing conditions, timing, treatment of non‑acceptable indications and repaired welds.
• Annexes:
  • Annex A (normative) - rules and standards to be applied.
  • Annex B (informative) - overview of welding quality standards and NDT standards.
  • Annex C (informative) - non‑acceptable indications for partial testing and a flowchart.

Practical applications and users

ISO 17635:2025 is used to:

• Develop NDT strategies and acceptance criteria in fabrication, construction and manufacturing.
• Integrate NDT into quality management for pressure vessels, pipelines, structural steel, shipbuilding, rail and heavy fabrication.
• Support procurement specifications, inspection plans and conformity assessment for welded metallic assemblies.

Primary users include NDT engineers, welding inspectors, quality managers, fabricators, third‑party inspection bodies, testing laboratories and consultants.

Related standards

• ISO 5817 - Welding - quality levels for imperfections (reference for quality categories).
• ISO 10042 - Welding - quality levels for fusion welded joints in steel (related quality guidance).
  ISO 17635:2025 provides the NDT selection and acceptance framework that complements these welding quality standards.

Keywords: ISO 17635:2025, non‑destructive testing, NDT for welds, metallic materials, acceptance levels, UT‑PA, UT‑TFM, welding inspection, NDT standards.