Overview
ISO 10893-6:2019 defines film-based radiographic X‑ray methods for non‑destructive testing (NDT) of the weld seam of welded steel tubes (longitudinal or helical) to detect imperfections. It applies to automated fusion arc‑welded tubes and can also be used for circular hollow sections. The standard specifies procedural requirements, image quality classes, film systems, film processing and reporting conventions. A digital alternative is ISO 10893-7.
Key topics and technical requirements
- Scope & timing: Radiographic inspection is performed after completion of primary production operations (rolling, heat treatment, sizing, straightening, etc.).
- Personnel: NDT operators must be trained and certified or qualified (e.g., ISO 9712, ISO 11484) and testing supervised by competent personnel.
- Image quality classes: Two classes - A (standard sensitivity) and B (enhanced sensitivity). Class B requires finer film systems and typically longer exposures.
- Film systems & screens: Minimum film system classes are specified (e.g., at least C5 for class A; higher requirements for class B). Salt intensifying screens are not permitted.
- Technique: Preferential use of the single‑wall penetration technique; double‑wall may be used by agreement. The radiation beam should be directed at the weld centre and normal to the tube surface.
- Geometry and exposure: Minimum source‑to‑weld distance and focal‑spot considerations are controlled (nomogram provided). Maximum X‑ray voltages are specified as a function of penetrated thickness (see Figure 2 in the standard).
- Image quality indicators (IQI): IQIs (wire or step/hole types per ISO 19232) are placed on the source side adjacent to the weld; film‑side placement is allowed only when the source side is inaccessible and must be recorded.
- Acceptance of coverage: Adjacent films must overlap by at least 10 mm to avoid unexamined weld length.
- Densities and fog: Minimum radiograph density of sound weld metal is specified (e.g., not less than about 2.0 for class A and 2.3 for class B); fog density limits are also given.
- Backscatter control & marking: Procedures to minimize backscatter (including a lead “B” test symbol) and marking/identification of radiographs are required.
- Safety: Strong warning to apply appropriate ionizing‑radiation safety measures and local regulations.
Applications and users
ISO 10893-6 is used by:
- Steel tube manufacturers for production QA of welded seams
- NDT technicians and Level 2/3 inspectors preparing and evaluating film radiographs
- Third‑party inspection bodies and purchasers specifying acceptance criteria in contracts
- Quality managers and engineering teams requiring documented radiographic weld inspection procedures
Practical applications include detection of porosity, lack of fusion, cracks and inclusions in weld seams of line pipe, structural tubes, mechanical tubing and circular hollow sections.
Related standards
Keywords: ISO 10893-6:2019, radiographic testing, welded steel tubes, NDT, weld seam inspection, film radiography, image quality, IQI, X‑ray radiography.
Open preview (PDF)Non-destructive testing of steel tubes — Part 6: Radiographic testing of the weld seam of welded steel tubes for the detection of imperfections