D.2.1 Length of tube
The length of tube may be plugged at both ends. The free length between each plug and the nearest gauge marks shall exceed D/4. In cases of dispute, the value D shall be used, as long as there is sufficient material.
The length of the plug projecting relative to the grips of the machine in the direction of the gauge marks shall not exceed D, and its shape shall be such that it does not interfere with the gauge length deformation.
D.2.2 Longitudinal or transverse strip
The parallel length ( ) of the longitudinal strips shall not be flattened but the gripped ends may be flattened for gripping in the testing machine.
Transverse or longitudinal test piece dimensions other than those given in annexes A and C can be specified in the product standard.
Special precautions shall be taken when straightening the transverse test pieces.
D.2.3 Circular cross-section test piece machined in tube wall
The sampling of the test pieces is specified in the product standard.