SIST EN ISO 17635:2025 PDF

Overview

EN ISO 17635:2025 - Non-destructive testing of welds provides general rules and guidance for selecting and applying non-destructive testing (NDT) methods to welded joints in metallic materials. Published by CEN and identical to ISO 17635:2025, the standard helps link quality requirements, material type, weld thickness, welding process and testing extent to the appropriate NDT method and acceptance criteria for quality control.

Key topics and technical requirements

• Method selection criteria: Guidance for choosing NDT methods based on quality requirements, material, weld thickness, welding process and extent of testing (partial or full).
• Acceptance levels: Defines acceptance-level principles for NDT results. Acceptance levels are linked to overall batch quality and are not a direct one-to-one interpretation of ISO 5817 or ISO 10042 quality grades, although they align generally (moderate, intermediate, stringent).
• Rules and standards to apply: Annex A (normative) lists rules and standards to be applied to different testing types and techniques.
• Standards mapping: Annex B (informative) provides an overview of specific NDT and welding quality standards that relate to testing levels and acceptance criteria.
• Partial testing guidance: Annex C (informative) covers non-acceptable indications when only partial testing is performed and includes a flowchart.
• Personnel and organization: Requirements for personnel qualification, testing organization, and documentation (testing plan, written procedures, test reports).
• Technique updates: The 2025 edition adds modern ultrasonic techniques such as phased-array ultrasonic (UT-PA) for thin-walled steel components and total focusing method (UT-TFM), and updates relevant tables and references.
• Testing execution: Provisions on timing, conditions for testing, handling non-acceptable indications, and repaired welds.

Applications and users

EN ISO 17635:2025 is practical for:

• Welding engineers and designers specifying weld inspection strategy
• NDT inspectors and testing companies planning and performing weld examinations
• Quality assurance / quality control managers in fabrication, aerospace, oil & gas, power generation and construction
• Fabricators and welding contractors implementing inspection plans and acceptance criteria
• Certification bodies and auditors assessing NDT processes and personnel competency

Practical uses include preparing testing plans, selecting appropriate NDT techniques (UT, RT, MT, PT and advanced UT-PA/UT-TFM), defining documentation requirements and setting acceptance criteria consistent with production quality.

Related standards

• ISO 5817 - welding quality levels (moderate, intermediate, stringent)
• ISO 10042 - quality and acceptance criteria for welds using thermal cutting/welding (referenced for compatibility)
• Specific NDT technique standards (UT, RT, MT, PT) are cross-referenced in Annex B for detailed procedural requirements.

For implementers, EN ISO 17635:2025 is a central reference when developing weld inspection strategies that balance technical feasibility, cost and required product quality.