Which is a good wire thermal extension device

KTR010Thermal extension device/thermal extension tester

Meets the requirements of national standards GB/T2951.21-2008 and GB/T 2951.5-1997 (Special Test Method for Elastomeric Mixtures - Thermal Extension Test), used to measure the elongation and deformation of insulation and sheath of wires and cables under thermal and load conditions, in order to determine material properties. The sample is suspended in the oven, and a weight is added to the lower clamp. After 15 minutes, the distance between the marks is measured and the elongation is calculated.

1thermal extension deviceTechnical Specifications:

1. Total length of ruler: 0-150mm, accuracy: 1mm

2. Balance weight: 1-500g three sets (each set has 12 weights:

1g one, 2g two, 5g one, 10g one, 20g two,

50g one, 100g two, 200g one, 500g one)

3. Three sets of test racks and trays each, capable of testing three samples simultaneously

4. Dimensions L * W * H approximately: 370 * 100 * 410mm

5. Material: The frame, clamp, and chuck are all made of stainless steel

IIthermal extension deviceTest Method

1. Sampling, sample preparation, and determination of cross-sectional area:

Cut two insulation and sheath sections from each test sample, prepare the test samples and measure the cross-sectional area according to the test method specified in Chapter 9 of GB/T2951.11-2008. Dumbbell specimens should be taken from the insulation and sheath after removing all ridges and/or semiconducting layers.

The thickness of the test piece should not be less than 0.8mm and not more than 2mm. If it is not possible to prepare a 0.8mm thick test piece, the minimum thickness is allowed to be 0.6mm. Mark a 20mm mark line in the middle of each large dumbbell specimen and a 10mm mark line in the middle of each small dumbbell specimen.

2. Experimental equipment

a) The experiment should be conducted in an oven as specified in section 8.1 of GB/T2951.12-2008

b) Each specimen in the oven should be suspended from the upper clamp, clamped with the lower clamp, and weighted on the lower rack head.

Note: When fixing a tubular specimen with a clamp, the two ends of the specimen should not be tightly closed. Appropriate methods can be used to achieve this, such as inserting a small section of metal needle tube at least at one end of the specimen, which is slightly smaller than the diameter of the specimen

3. Experimental steps

a) The specimen is suspended in the oven and a weight is added to the lower clamp. The generated force shall be in accordance with the relevant materials specified in the cable product standards. The suspension process should be as fast as possible to minimize the opening time of the oven.

b) When the temperature of the oven rises to the specified temperature, the specimen is kept in the oven for another 10 minutes, and the distance between the marked lines is measured and the elongation is calculated. If the oven does not have an observation window and the door must be opened for measurement, the measurement should be completed within 30 seconds of opening the door.

If there is any dispute, the test should be conducted in an oven with an observation window, and the measurement should be taken without opening the box door

c) Then release the tension from the specimen (cut off the specimen at the lower clamp), and leave the specimen in the oven for recovery. Leave the specimen in the oven for 5 minutes, or wait until the oven temperature returns to the specified temperature for a longer period of time. Then take out the specimen from the oven, slowly cool it to room temperature, and measure the distance between the marked lines again.

Note: Appropriate protective measures must always be taken during the testing process to avoid damage that may be caused by thermal clamps, loads, and specimens.

4. Determination of experimental results

a) After being loaded for 10 minutes at the specified temperature, the median elongation should not exceed the specifications of the relevant cable product standards

b) The percentage of the increase in the distance between the marked lines after the test piece is taken out of the oven and cooled shall not exceed the relevant cable product standards before the test piece is placed in the oven.

3、 Parameter setting and calculation

1. Temperature setting: 180 ℃ for rubber products and 200 ℃ for cross-linked polyethylene products.

2. When the temperature reaches the desired level, clamp the dumbbell test piece onto the hot extension fixture and add it below

Balance the weight.

3. Weight calculation: 20.4 x specimen thickness x 4 (including clamp, support rod, and weight).

4. 20mm in length at the effective distance in the middle of the dumbbell specimen (the length of the small dumbbell specimen is 10mm)

Three dumbbell pads should be taken from the marking line of the degree, and the entire set of thermal extension devices should be placed in the aging chamber that has been heated to the desired temperature. Close the door of the aging chamber and quickly read the elongation length of the sample after 15 minutes.

5. Thermal extension calculation

After being loaded for 10 minutes at the specified temperature, measure the percentage of deformation length relative to the distance of the marking line before placing the specimen in the oven

The thermal elongation of a 75mm dumbbell specimen is calculated as (aging length -20)/20

The thermal elongation of a 50mm dumbbell specimen is calculated as (aging length -10)/10

6. Deformation rate:

Remove the hot stretched test piece from the aging chamber, cool it to room temperature, and measure its effective length (i.e. deformation length)

Deformation rate of 75mm dumbbell specimen=(deformation length -20)/20

The deformation rate of a 50mm dumbbell specimen is (deformation length -10)/10

7. National standards

Thermal elongation rate ≤ 175%, qualified deformation rate ≤ 15%, qualified

4thermal extension deviceAging test measurement method

1. Temperature setting

Polyvinyl chloride material at 80 ℃; Cross linked polyethylene material at 100 ℃; Fluoroplastic material at 200 ℃.

2. Aging time 7 × 24 hours.

3. Place the dumbbell test piece vertically in the middle of the aging chamber.

4. After aging, remove the dumbbell test piece and cool it at room temperature for 16 hours before conducting a tensile test.