Tensile Testing of Pipe and Tube to ASTM A370, ISO 6892-1, API 5L, and ISO 3183
The quality and integrity of steel pipe used in oil casing and pipeline transportation systems is subject to stringent mechanical testing requirements. ASTM A370, ISO 6892-1, API 5L, and ISO 3183 all contain tensile testing procedures for tubular products, and meeting these requirements presents a range of practical challenges depending on the shape of the pipe, its wall thickness, and the radius of curvature. Instron offers a comprehensive range of testing systems, gripping solutions, and extensometers to address these challenges and ensure accurate, standards-compliant results.
The Challenges of Tensile Testing Pipe and Tube
- Gripping full section pipe and tube without crushing or deforming the specimen ends
- Obtaining accurate and repeatable strain measurements on curved or irregular specimen surfaces
Our Solutions
Specimen Gripping
Where possible, testing full section pipe is preferred by both pipe manufacturers and test laboratories, as it eliminates the time and cost associated with specimen preparation. However, full section pipe must be plugged at each end to prevent the ends from crushing under the gripping force during the tensile test.
When the full section pipe is too large to be accommodated by the test frame or gripping system, longitudinal strip specimens are cut from the tubular product as described in the relevant standards. These specimens have an irregular curved cross-section that requires careful fixture design to ensure accurate, centered loading.
Instron offers a range of end plug sizes designed with a recessed lip for easy removal after testing. For full section testing, we recommend a fully open hydraulic gripping configuration for ease of use, enhanced operator safety, and secure, slip-free gripping of the material.
Strain Measurement
ASTM A370, ISO 6892-1, API 5L, and ISO 3183 all require a gauge length of 2 inches (50 mm) for strain measurement. Instron offers several extensometer options to meet this requirement across different specimen types and sizes:
- Full section pipe — An industrial-style clip-on extensometer is available for full section pipe specimens up to 89 mm in diameter, providing reliable strain measurement on large curved surfaces.
- Longitudinal strip specimens — A smaller frame clip-on extensometer is available that fits snugly against both the inner and outer diameter of the strip specimen, preventing slippage on the irregular curved surface and ensuring measurement accuracy.
- Automatic extensometry — Automatic extensometers are also available for applications requiring faster specimen throughput or reduced operator intervention during testing.
Recommended System
For tensile testing of pipe and tube products, Instron's most widely used system is the Industrial Series 1000HDX — a high-force hydraulic universal testing system suited to the demands of large section pipe testing. The fully open hydraulic gripping configuration provides easy specimen loading, enhanced safety, and secure gripping without slippage.
Bluehill® Universal software provides pre-built test methods for ISO 6892-1, ASTM A370, API 5L, and ISO 3183, reducing setup time and ensuring your testing process is fully compliant with the relevant standard requirements.
Talk to an Instron Expert
Whether you are testing full section pipe or longitudinal strip specimens, Instron has the systems, gripping solutions, and extensometers to meet the requirements of ASTM A370, ISO 6892-1, API 5L, and ISO 3183.
Contact Sales to discuss your pipe and tube testing requirements with our team.
