Tensile test on steel pipes

Tensile testing on pipes or pipe strip specimens with universal testing machines of the inspekt series in a load range from 400 kN to 2500 kN

Most of the testing systems are equipped with parallel closing hydraulic grips, which guarantee a high clamping force that can be adjusted constantly or proportionally over the duration of the test.

The test systems are designed for tensile tests on pipe and pipe strip specimens (according to DIN EN ISO 6892-1:2020). The tests can be carried out both strain-controlled according to procedure A and stress-controlled according to procedure B. Tests with constant pull-off speed are also possible.

Pipes with smaller outside diameters can be tested as a complete workpiece. In this case, the pipe ends are clamped in the hydraulic grip and either pressed together or reinforced from the inside with a plug, thus avoiding preliminary damage during clamping.

For larger pipe diameters, tensile specimens are often taken from the pipe wall. The tensile tests are used to determine strength and deformation parameters such as yield strength, tensile strength and elongation at break. Of course, the increase in the elastic section of the stress-strain curve can also be determined.

For strain measurement on longitudinally welded pipe specimens, which are clamped in a compressed manner and where concave warping occurs during the tensile test, special measuring arms of the extensometer are used to ensure that the contact between the cutting edge and the specimen remains until breakage. The double cutting edge consists of round cutting edges made of hardened HSS working steel with high adhesive and abrasive wear resistance combined with high toughness and compressive strength. Due to the folding mechanism, the energy is diverted away during breakage and not transferred to the incremental displacement measuring system, which is particularly advantageous for brittle breaking materials and for the protection of the test system.

Optionally, the test systems can be equipped with a measuring station for length measurement and weighing of the pipe specimens.

Video about tensile test on steel pipes