Semi hard casing bending teste

  Bending testing machine for semi-rigid casing and corrugated casing I
preface
  This testing machine is applicable to the bending test of semi-rigid casing, and the bending angle is 90 DEG;, After the test, observe the sample for cracks
It is produced in accordance with national specifications: jg/t3050 insulating electrical sleeve and accessories for building and zbg33008 PVC corrugated wire pipe

2、 technical parameter
  Jg3050-10a1 semi hard casing bending tester
Sample conduit diameter: , 16、20、25mm。
Bending inner radius: , 96、120、150mm。
Total bending angle of sample: , 90°
Overall dimension: , 650× 350× 470mm
, Quantity: , 54kg
3、 Structure description
  The testing machine is composed of base, support, forming die, bending roll device, etc

4、 Operation
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1 place the testing machine stably and wipe the surface clean

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2 before the test, first insert the bending auxiliary part into the sample
The bending auxiliary part can be a dense coil spring wound by a burr free steel wire with a diameter of 1-2mm (the outer diameter of the spring is 0
7-1mm smaller than the minimum inner diameter of the specified conduit)
Or use the bending auxiliary parts recommended by the manufacturer

The length of the specimen is 30 times the nominal diameter,
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3 insert the sample into the groove between the forming dies (wheels)

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4 press down the sample slowly so that the total bending angle of the sample is about
120°， So that when the profile roll is released, the sample is bent to 90 DEG; Angle, at 90 DEG; In this position, the angle shall be without damaging the specimen and bending auxiliary parts

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5 take 6 samples for semi-rigid casing and corrugated casing, and the length of each sample shall be at least:
1) Semi rigid casing: the length is 30 times of its outer diameter

2) Bellows: the length is 12 times of its outer diameter

Among them, 3 samples are tested at normal temperature, and 3 samples are put into the low-temperature box
The temperature control in the low-temperature box is as follows: 1) - 5 and 90 casing, and the temperature of the low-temperature box is - 5 ℃ & plusmn; 2℃

2) - 15, - 25 and 90 / - 25 casing, the temperature of low temperature chamber is - 15 ℃ ± 2℃

Take out the casing treated in the low-temperature box for test immediately, and place the casing vertically in the specified bending test device for bending test
The bending radius shall comply with the requirements specified in the specification
First bend to the left for about 90 degrees, then return to the vertical position, and then bend to the right for about 90 degrees after 1min, and then return to the vertical position for 1min
Repeat the above operation for 4 times
At the last time, do not bend the sample back to the vertical position, but keep it in the bending position at 45 degrees from the vertical line for 5min, and then turn one end of the casing upward and one end downward, and select the corresponding gauge according to the regulations, The gauge shall be able to slide freely from the pipe under its own weight
After the test, there shall be no visible cracks on the surface of 6 samples, and the gauge can slide out of the casing freely