Overview
ISO 10893-9:2011 defines requirements for automated ultrasonic testing (AUT) of steel strip and plate used to manufacture welded steel tubes. The standard covers detection of laminar imperfections (imperfections parallel to the surface) when testing is performed in the flat strip/plate form before or during pipe production. It is also applicable, by agreement, to testing strip/plate for circular hollow sections or to SAW tube strip segments after seam welding. Keywords: ISO 10893-9, automated ultrasonic testing, laminar imperfections, welded steel tubes, NDT.
Key topics and requirements
- Test techniques: Pulse-echo with normal incidence or ultrasonic through-transmission for laminar flaw detection.
- Scanning geometry: Strip/plate and probe assembly must move so surfaces are scanned along equidistant scan lines parallel or transverse to the rolling direction. Coverage and maximum gaps are defined by acceptance level (U1, U2, U3):
- U1: minimum coverage 20%, max gap 100 mm
- U2: minimum coverage 10%, max gap 150 mm
- U3: minimum coverage 5%, max gap 200 mm
- Edge testing: Longitudinal edges must be 100% ultrasonically tested over at least 15 mm plus any edge material to be removed before seam welding. Minimum detectable imperfection lengths and maximum acceptable sizes are specified per acceptance level (e.g., U1/U2/U3 thresholds; only laminations wider than 6 mm are considered).
- Reference standards and calibration: Calibration using a flat reference sample or a machined flat-bottomed recess (primary: circular flat-bottomed recess). Reference recess dimensions are specified (width ≈ 6 mm; depth between T/4 and T/2, max 25 mm; length ≥ 6 mm, max 25 mm).
- Equipment checks: Initial calibration and routine checks are required - at least every 4 hours, at start/end of runs and on operator changeover. Recalibration is required if parameters change or if drift exceeds allowances.
- Probes: Suggested maximum probe (or active aperture) width is 25 mm; phased-array aperture rules apply.
- Personnel: Operators must be qualified per ISO 9712, ISO 11484, or equivalent; NDT authorization and Level 3 oversight are required.
- Automation & sorting: AUT systems must classify material as acceptable or suspect and provide automated trigger/alarm plus marking/sorting.
Applications and users
- Primary users: Tube mills, strip/plate manufacturers, quality and NDT engineers, and third-party inspection services involved in welded steel tube production.
- Practical uses: Inline quality control of incoming strip/plate, process control during tube manufacturing, pre-weld inspection to prevent laminar defects from entering welded seams, and acceptance testing for circular hollow section feedstock.
- Benefits: Early detection of laminar imperfections reduces scrap, prevents weld defects, and supports traceable NDT calibration and reporting.
Related standards
- ISO 10893 series (Parts 1–12) - other NDT methods for steel tubes (e.g., Part 8: AUT of tubes after seam welding; Part 10/11: other ultrasonic inspection methods).
- ISO 9712 and ISO 11484 - personnel qualification and employer qualification systems for NDT.
This summary helps engineers and quality managers understand the scope and practical implementation of ISO 10893-9 for reliable automated ultrasonic inspection of strip/plate used in welded steel tube manufacture.