How To Measure The Tensile Properties Of Rubber O-rings?

Tensile performance is a test to determine a series of characteristics of rubber O-rings under tensile load, also called tensile test. It is one of the basic methods of material mechanical performance test, mainly used to check whether the material meets the specified standards and study the performance of the material.

Test Instruments

(1) This test is carried out on a tensile machine, which should comply with the relevant provisions of GB/T 528-1998 "Determination of Tensile Stress and Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The tensile machine needs to have a guiding rack device and a device for measuring the elongation of the sample

(2) The test fixture is composed of upper and lower two axle wheels with ball bearings with a diameter of at least 12mm. When the two wheels are close to each other, the new distance is within 25mm. The lower clamp is equipped with a gear transmission device, which should be toothed with the guide rack on the tensile machine during the test

(3) The linear test fixture adopts the universal tensile test fixture, but it is necessary to ensure that the sample is kept in the clamp during the test.

Sample

(1) The inner diameter of the standard sample is 40mm±0.3mm, and the cross-sectional diameter is 3.55mm±0.1mm. The number of samples is 5

(2) O-rings of other sizes with an inner diameter greater than 40mm, or fragments cut from the o-rings (linear specimens with a length not less than 120mm) can be used for measurement, and the results cannot be compared with the results of standard samples

Sample step

(1) Measure the cross-sectional diameter and inner diameter of the sample as required. If it is a linear sample, it shall be carried out in accordance with the methods in Article 4.2.4 and 4.2.5 of GB/T 528. The distance between the marking lines of the working part is 25mm

(2) Put the rubber O-ring on the axle wheels of the upper and lower fixtures as close as possible to prevent the sample from tensile stress, connect the elongation measurement system, and adjust the zero point (that is, determine the inner circumference of the O-ring When the elongation is equal to zero, the center distance of the two axle wheels)

(3) Start the machine to stretch the sample at a speed of (500±50) mm/min, and record the load when the sample is stretched to the specified extension, the load and the amount of extension when it breaks

Expression of test results ---- The measurement results are 5, the test results take the median of the calculated results, the elongation at break is rounded to one digit, and the tensile stress and tensile strength are taken to one decimal place.