Overview - What ISO 11970:2025 covers
ISO 11970:2025, "Specification and qualification of welding procedures for production welding of steel and nickel‑base castings", defines how welding procedure specifications (WPS/pWPS) for production welding are qualified. The standard sets out the conditions for performing welding procedure qualification tests, the limits of validity for a qualified welding procedure within the range of essential variables, and the required records (WPQR). Although the title covers steel and nickel‑base castings, the scope explicitly applies to the arc welding of steel castings; the principles can be applied to other fusion processes by agreement between contracting parties.
Key technical topics and requirements
- Preliminary WPS (pWPS): preparation of a pWPS specifying relevant process parameters in accordance with ISO 15609 (Clause 4).
- Welding procedure qualification: making and testing of specimens to represent production welding types and positions (Clause 5).
- Test piece design and welding: guidance on shapes, dimensions and welding of test pieces (Clause 6), including allowance for additional/longer pieces for retesting.
- Examination and testing: mandatory combination of non‑destructive testing (NDT) and destructive tests (Clause 7). Specific examinations referenced include:
- NDT methods (magnetic particle, liquid penetrant, ultrasonic, radiographic) per related ISO standards,
- Destructive tests such as transverse tensile, macro‑ and micro‑examination, impact testing (Charpy), and hardness testing (Clauses 7.3–7.4).
- Range of qualification: rules covering manufacturer, parent material grouping and thickness, welding process, positions, joint type, filler metal, electrical parameters, heat input, preheat, interpass and post‑weld heat treatment (Clause 8).
- Qualification records: completion and retention of a Welding Procedure Qualification Record (WPQR), with a model record form in Annex A (Clause 9, Annex A).
- Welder qualification linkage: welders performing the qualification are approved in the relevant test area per ISO 9606‑1, with additional welder qualification guidance (Clause 7.6).
Practical applications and users
ISO 11970:2025 is used by:
- Foundries and steel/nickel‑base casting manufacturers to establish qualified production welding procedures.
- Welding engineers and QA/QC managers for procedure validation, test planning and acceptance criteria.
- Purchasers and contract parties to specify additional tests or accept qualified procedures.
- Inspection bodies and certification organizations for auditing and confirming compliance with welding procedure qualification requirements.
Use cases include joint welding of cast components, finishing welds to achieve casting quality, and developing WPQRs for serial production.
Related standards
Relevant referenced documents include:
- ISO 15607, ISO 15609 (WPS and general rules)
- ISO 9606‑1 (welder qualification)
- ISO 5817 (weld quality levels)
- ISO 148‑1, ISO 4136, ISO 9016, ISO 9015‑1 (impact, tensile, hardness tests)
- NDT standards: ISO 4986, ISO 4987, ISO 4992‑1/2, ISO 4993
- Metallography and hardness: ISO 4969, ISO 6507‑1
Consult these normative references when applying ISO 11970:2025.
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