Overview - ISO 4993:2024 (Radiographic testing of steel and iron castings)
ISO 4993:2024 specifies the general requirements for radiographic testing of steel and iron castings using X‑rays or gamma‑rays. This fourth edition updates radiographic practice for foundries and inspection bodies, covering pilot and production radiography, safety considerations for ionizing radiation, and documentation requirements such as film position plans and traceability of radiographs or digital images.
Key topics and technical requirements
- Scope and purpose: Radiographic testing to detect internal discontinuities in steel and iron castings (density variations detectable by radiography).
- Testing parameters: Radiography may be performed at any manufacturing stage (before or after final heat treatment). Surface conditioning and image quality requirements must be agreed between purchaser and manufacturer.
- Film position plan: Detailed instructions for pilot and production radiography, including source type (X‑ray or gamma), source size, geometry (object‑to‑film and film‑to‑source distances), beam angle, exposure data, film/screen type, IQIs/penetrameters and image quality value (per ISO 19232 series).
- Image quality and evaluation: Radiographs are evaluated by comparison with reference radiographs; sensitivity and image quality values follow the ISO 19232 series. Digital or film reference images are permitted.
- Personnel qualifications: Operators and evaluators must be qualified according to ISO 9712 (NDT personnel certification).
- Testing arrangements: Guidance for single‑wall, double‑wall and complex geometries is given (Annex A). Special limits (e.g., angle of incident radiation not to exceed 30° in some double‑wall cases) and techniques to extend thickness range (Annex B) are included. Source selection guidance appears in Annex C.
- Acceptance/rejection: Acceptance criteria are specified by contract and typically reference applicable ASTM standards for reference radiographs or digital reference images.
- Foundry responsibility: Manufacturer obligations are limited to meeting the agreed criteria and testing arrangements stated in the purchase order.
Practical applications - who uses ISO 4993:2024
- Foundries producing steel and iron castings that require internal integrity verification.
- NDT laboratories and service providers performing radiographic inspections with X‑rays or gamma‑rays.
- Quality managers, purchasing engineers and inspectors defining inspection requirements, acceptance criteria and film position plans.
- Design and maintenance engineers in industries (automotive, heavy machinery, energy, aerospace supply chains for cast components) needing reliable internal defect detection.
Related standards
- ISO 5579 - Radiographic testing of metallic materials: basic rules
- ISO 19232 (Parts 1–5) - Image quality of radiographs (IQI and image quality values)
- ISO 9712 - Qualification and certification of NDT personnel
- Relevant ASTM standards for reference radiographs/digital reference images (e.g., ASTM E186, E280, E446, E8268, E2660)
ISO 4993:2024 is essential when specifying contract radiography for castings, ensuring consistent testing geometry, documented film plans, qualified personnel and traceable image quality for reliable defect detection.
