Tensile specimens Marking device Flat specimens / sheets

Marking device for marking flat samples in seconds

Inserting, lowering, pressing, removing <5 seconds
 

This marking device makes it easy to mark tensile specimens/flat specimens so that the elongation at break can then be measured manually. The markings are scratched in. For most materials, these have no influence on the test result. The marking device is suitable for all flat specimens with a length Lt of up to 300 mm and a specimen thickness of up to 15 mm.

marking process:

1. lifting the moving part
2. Insert sample centrically
3. Lower the marking bar and place scribers on the flat sample
4. Press the marking bar with more or less force and press down the long lever:
5. The rotary motion moves the scriber needles over the flat sample and creates scratch marks with a spacing of 5 mm over a length of 120 mm (25 marks)
6. Lift the marking bar, remove the sample and immediately insert a new sample
    

Fracture strain measurement / determination Lu using calipers

• If the purchase of a costly long-stroke extensometer is not advisable due to a low sample volume, other methods must be used to accurately determine the elongation at break (in accordance with standards!).
• For critical applications, it is sometimes also necessary to determine the elongation at break by measuring the sample in a conventional manner (e.g. when the sample breakage occurs near or outside the cutting edges).
• Furthermore, manual measurement of the elongation at break according to various standards is mandatory (ASTM / NADCAP / BS / API).

Procedure: To determine the elongation at break, the broken sample is placed on a (magnetic) plate and joined together. To make counting easier, the counted segment distances are marked with a permanent marker (EDDING) and the Lu to be measured (L0 after sample extension) is found in this way. Ideally, this measurement value is determined with an electronic caliper and transferred to the open field of the test software at the touch of a button.

The device is suitable for all sample shapes at the same time: For a flat sample with a parallel length of 120 mm, the measuring marks are applied at a distance of 5 mm for a distance of 120 mm (e.g. Lc of a non-proportional flat sample / tensile sample DIN 50125 – H 20 × 80.