How To Determine The Tensile Properties Of Rubber O-rings?
May 31, 2020
Tensile performance is a test to determine a series of characteristics of rubber O-rings under tensile load, also known as tensile test. It is one of the basic methods for testing the mechanical properties of materials. It is mainly used to check whether the materials meet the specified standards and to study the properties of the materials.
Test Instruments
(1) This test is carried out on a tensile machine, which shall comply with the relevant provisions of GB / T 528-1998 "Determination of Tensile Stress and Strain Properties of Vulcanized Rubber or Thermoplastic Rubber". The tension machine needs a guide rack device and a device to measure the elongation of the sample
(2) The test fixture is composed of two shaft wheels with ball bearings with a diameter of at least 12mm at the top and bottom. When the two wheels are close to each other, the new distance is within 25mm. The lower fixture is equipped with a gear transmission device, which should be in line with the guide rack teeth on the tension machine during the test
(3) The linear test fixture uses the universal tensile test fixture, but it is necessary to ensure that the sample is constantly in the clamping place 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) Other sizes of o-rings with an inner diameter greater than 40mm, or fragments cut from o-rings (linear specimens with a length of not less than 120mm) can be used for measurement.
Sample steps
(1) Measure the cross-sectional diameter and inner diameter of the sample as specified. If it is a linear sample, it shall be carried out in accordance with the methods in 4.2.4 and 4.2.5 of GB / T 528. The marking distance of the working part is 25mm
(2) Place the rubber O-ring on the shaft wheel of the upper and lower clamps 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 between 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 elongation, the load and elongation when it is broken
Representation of test results ---- The measurement results are 5, the median of the test results is taken as the calculation result, the elongation at break is taken as the whole number, and the fixed tensile stress and tensile strength are taken as one decimal.
