EN ISO 17635:2025
(Main)Non-destructive testing of welds - General rules for metallic materials (ISO 17635:2025)
General Information
- Abstract
This document gives guidelines for the choice of non-destructive testing (NDT) methods for welds in metals and for the evaluation of the results for quality control purposes, based on quality requirements, material, weld thickness, welding process and extent of testing.
This document also specifies general rules and standards to be applied to the different types of testing, for the selection of the method, the techniques and the acceptance levels.
Acceptance levels cannot be a direct interpretation of the quality levels defined in ISO 5817 or ISO 10042. They are linked to the overall quality of the produced batch of welds.
The requirements specified in this document for acceptance levels for NDT conform with quality levels stated in ISO 5817 or ISO 10042 (moderate, intermediate, stringent) only on a general basis and not in detail for each indication.
Annex A gives correlations between quality levels, testing levels and acceptance levels for specific testing techniques.
Annex B gives an overview on specific testing techniques of standards linked to quality levels, acceptance levels and testing methods.
- Status
- Published
- Publication Date
- 15-Apr-2025
- Technical Committee
- CEN/TC 121 - Welding
- Drafting Committee
- CEN/TC 121/WG 21 - Testing of welds
- Current Stage
- 6060 - Definitive text made available (DAV) - Publishing
- Start Date
- 16-Apr-2025
- Completion Date
- 16-Apr-2025
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.
Relations
- Effective Date
- 05-Oct-2022
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Refers
ISO 23278:2015 - Non-destructive testing of welds — Magnetic particle testing — Acceptance levels - Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 09-Feb-2026
- Effective Date
- 09-Feb-2026
- Effective Date
- 09-Feb-2026
- Effective Date
- 09-Feb-2026
Get Certified
Connect with accredited certification bodies for this standard
National Aerospace and Defense Contractors Accreditation Program (NADCAP)
Global cooperative program for special process quality in aerospace.
CARES (UK Certification Authority for Reinforcing Steels)
UK certification for reinforcing steels and construction.
DVS-ZERT GmbH
German welding certification society.
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Frequently Asked Questions
EN ISO 17635:2025 is a standard published by the European Committee for Standardization (CEN). Its full title is "Non-destructive testing of welds - General rules for metallic materials (ISO 17635:2025)". This standard covers: This document gives guidelines for the choice of non-destructive testing (NDT) methods for welds in metals and for the evaluation of the results for quality control purposes, based on quality requirements, material, weld thickness, welding process and extent of testing. This document also specifies general rules and standards to be applied to the different types of testing, for the selection of the method, the techniques and the acceptance levels. Acceptance levels cannot be a direct interpretation of the quality levels defined in ISO 5817 or ISO 10042. They are linked to the overall quality of the produced batch of welds. The requirements specified in this document for acceptance levels for NDT conform with quality levels stated in ISO 5817 or ISO 10042 (moderate, intermediate, stringent) only on a general basis and not in detail for each indication. Annex A gives correlations between quality levels, testing levels and acceptance levels for specific testing techniques. Annex B gives an overview on specific testing techniques of standards linked to quality levels, acceptance levels and testing methods.
This document gives guidelines for the choice of non-destructive testing (NDT) methods for welds in metals and for the evaluation of the results for quality control purposes, based on quality requirements, material, weld thickness, welding process and extent of testing. This document also specifies general rules and standards to be applied to the different types of testing, for the selection of the method, the techniques and the acceptance levels. Acceptance levels cannot be a direct interpretation of the quality levels defined in ISO 5817 or ISO 10042. They are linked to the overall quality of the produced batch of welds. The requirements specified in this document for acceptance levels for NDT conform with quality levels stated in ISO 5817 or ISO 10042 (moderate, intermediate, stringent) only on a general basis and not in detail for each indication. Annex A gives correlations between quality levels, testing levels and acceptance levels for specific testing techniques. Annex B gives an overview on specific testing techniques of standards linked to quality levels, acceptance levels and testing methods.
EN ISO 17635:2025 is classified under the following ICS (International Classification for Standards) categories: 25.160.40 - Welded joints and welds. The ICS classification helps identify the subject area and facilitates finding related standards.
EN ISO 17635:2025 has the following relationships with other standards: It is inter standard links to EN ISO 17635:2016, ISO 11666:2018, ISO 13588:2019, ISO 10863:2020, ISO 9712:2021, ISO 10675-2:2021, ISO 23278:2015, ISO 23277:2015, ISO 5817:2023, ISO 17640:2018, ISO 15626:2018, ISO 10675-1:2021, ISO 19285:2017, ISO 17637:2016, ISO 4761:2022. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN ISO 17635:2025 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.