Test Background
Creep relaxation refers to the phenomenon that strain increases inversely as stress decays. For polymer materials, because of their anvil elasticity, this creep relaxation phenomenon is even more obvious. Like stress relaxation, it is due to slippage between molecules within the material and other reasons. Part of the elastic strain of the material is gradually converted into irreversible plastic strain. The purpose of the non-metallic gasket material creep relaxation rate test is to determine the creep relaxation rate of type 1, type 5 and type 7 materials.
Zhongke Testing Reliability Experiment Center has the capability to test the reliability performance of various non-metallic gasket materials, and provides professional reliability testing services such as creep relaxation rate test, tensile strength test, softness test, compression rate rebound rate test and other non-metallic gasket materials.
Test method
Test method A
It is usually carried out at room temperature. The stress is measured by calibrated strain gauges on the bolts. The sample is placed between two flat circular plates and subjected to pressure. The pressure is provided by the bolts and nuts that tightly fasten the circular plates. During the test, the readings on the strain indicator are taken at regular intervals from the beginning of loading to the end of the test.
The readings on the strain gauge are converted to a percentage of the initial stress and then plotted versus the logarithm of time in hours. The percentage of initial stress loss or relaxation at any given time over the entire test time range can be detected from the curve.
Test methodB
Performed at room temperature or high temperature, the stress is determined by measuring the length change of a calibrated bolt with a dial gauge. The sample is placed between two flat circular plates and subjected to pressure. The pressure is provided by the bolts and nuts that tightly fasten the circular plates.
At the beginning and end of the test, the length of the bolt was measured and the creep relaxation rate was calculated.
Test standard:
GB/T 20671.5-2020 Non-metallic gasket material classification system and test methods Part 5: Gasket material creep relaxation rate test method
GB/T 20671.1 Non-metallic gasket material classification system and test methods Part 1: Non-metallic gasket material classification system
