tensile specimen marking device

With these partial devices / marking devices, tensile specimens can be marked in the simplest way in order to be able to measure the elongation at break manually after the test. The marking is scratched into the surface and not struck. It therefore has no influence on the test result. Round specimens (pipes, Rods, reinforcing steel) and flat samples (square tubes, flat samples made of hot strip, flat samples made of thin sheet) can be marked quickly and easily.

Depending on the marking device selected, divisions of 10 or 5 mm are possible. A dividing device with quickly interchangeable rollers can be offered as an option. The sample is clamped using two clamps. All division marks are applied with just two turns of the crank. Thanks to the spring-loaded marking needles / scoring needles, very even markings are achieved with little wear on the tips. The dividing machine is placed on a table and achieves good stability due to its own weight.

To determine the elongation at break, the broken sample is positioned in a support prism (special accessory) so that the axes of the two fragments form a straight line. The extension (Lu) is then measured using a caliper. If the small number of samples means that the purchase of an expensive long-stroke extensometer is not advisable, other methods must be used to determine the elongation at break precisely. For critical applications, it is sometimes necessary to determine the elongation at break by measuring the sample in a conventional manner. Furthermore, manual measurement of the elongation at break is mandatory according to various standards (ASTM / NADCAP / BS / API).

And last but not least, it must be clearly stated: Some samples that do not show a reduction in the L0 / Lc range (pipes, parallel strips, reinforcing steel, square tubes, rod material) tend to crack eccentrically. If the extension of the sample occurs outside the measuring sensors (outside the cutting edge distance Le), no exact results in relation to the A values ​​are possible and the test using the long-distance extensometer must be rejected. 

The marking device (dividing device) manufactured in Germany is efficient in operation and applies the desired sample marking in seconds:

1. Insert sample rod
2. closing clamps
3. Turn the crank twice, done

This marking device is available in different versions and divisions:

• MA200- 5 – Marking length 200 mm in increments of 5 mm
• MA200-10 – Marking length 200 mm in increments of 10 mm
• MA300- 5 – Marking length 300 mm in increments of 5 mm
• MA300-10 – Marking length 300 mm in increments of 10 mm
• with split tension clamps for reinforcing steel crosses
• other marking lengths on request