rubber Thermal extension device , rubber testing instrument

the test standard
It complies with the GB/T2951-2008 standard and other provisions of the device GB5013-2008, which must be used in conjunction with the 401A aging test chamber.
1, weight: 1, 2, 5, 10, 20, 50g
2, 150mm stainless steel ruler
3. Material: stainless steel
4, weight: about 2kg

sampling
Preparation of sample and determination of cross-sectional area. Two insulating samples and sheath samples were cut from each sample to be tested. The samples were prepared according to the test method specified in Chapter 9 of GB/T2951.1 and the cross-sectional area was measured. experimenting.
The dumbbell test piece should be taken from the inner layer of the insulation and sheath after removing all ridges or semi-conductive layers.
The thickness of the test piece shall be not less than 0.8 mm and not more than 2.0 mm. If a 0.8 mm thick test piece cannot be prepared, the minimum thickness is allowed to be 0.6 mm.

the test equipment
a test shall be carried out in an oven as specified in Article 8.1 of GB/T2951.2-1997. The test temperature is in accordance with the relevant materials in the relevant cable product standards.
b Each test piece in the oven should be suspended from the upper collet, clamped with the lower collet, and weighted on the lower collet.
Note: When fixing the tubular test piece with the collet, the test piece should not be tightly closed at both ends. This can be achieved by any suitable method, such as inserting a small piece of metal needle at one end of the test piece, which is slightly smaller than the inner diameter of the test piece.

the test steps
a test piece should be hung in the oven and the lower chuck will be weighted. The resulting forces are specified in the relevant materials in accordance with the relevant cable product standards.
b After 15 minutes in the oven, the distance between the marking lines was measured and the elongation was calculated. If the oven does not have an observation window and the door must be opened for measurement, it should be measured within 30 s after opening the door. The oven temperature is specified in the relevant materials according to the relevant cable product standards. In case of dispute, the test shall be carried out in an oven with an observation window and the door shall not be opened for measurement.
c Then remove the tension from the test piece (cut the sample at the lower chuck) and allow the test piece to recover at the specified temperature for 5 min. The test piece was then removed from the oven, slowly cooled to room temperature, and the distance between the marking lines was measured again.

Evaluation of test results
After a load of 15 min at the specified temperature, the intermediate value of elongation shall not be greater than the relevant provisions of the cable product standard.
The median value of the increase in the distance between the marking lines after the test piece is taken out of the oven is not greater than the relevant cable product standard before the test piece is placed in the oven.