How to test the tensile strength of rubber and elastomer materials according to ISO standard?
ISO 37 is used across a wide range of industries to measure the tensile stress-strain properties of vulcanized and thermoplastic rubbers. It is similar but not equivalent to ASTM D412, and most companies will test to one standard or the other depending on where in the world they are located.
ISO 37 is commonly used by companies engaged in raw material manufacturing, development of elastomer technology, and manufacturing of rubber-based consumer products and medical supplies, such as rubber gloves. ISO 37 is also a very common standard used by the energy and automotive sectors, particularly tire manufacturers. This guide is designed to introduce you to the basic elements of an ISO 37 tensile test, including an overview of the equipment, software, and samples needed. However, anyone planning to conduct ISO 37 testing should not consider this guide an adequate substitute for reading the full standard.
Note to grip and specimens
ISO 37 includes two different specimen shapes, dumbbell and o-ring, with dumbbell being the most common. Elastomers are high elongation materials that often thin significantly when load is applied, so it is best to use pneumatic side-action grips or self-tightening roller grips for testing
The software used for the tensile test of elastomer and rubber materials is Bluehill Universal software. Inside the software has been pre-configured for applications and tests according to different standards including ISO 37. And of course there will be two separate methods for testing 2 types of pestle and O-shaped samples.
How to measure the elongation of the elastic material when conducting the test?
Both contacting and non-contacting extensometers meet the accuracy requirements of ISO 37. Instron’s AVE2 is a highly versatile non-contacting solution and can be purchased with a 6mm Extra Long FoV Lens which is ideal for measuring elastomers. The AVE2 is the best solution for measuring delicate specimens as it makes no contact with the specimen and can be used for testing high-elongation elastomers.
The tip to help you make this test asily and accurately:
- Dumbbell specimens for testing to ISO 37 should always be cut parallel to the grain of the material, unless results comparing machine direction and cross direction are required. In this case, an equal number of each specimen type should be tested.
Reference the related systems for the tensile test rubber, elastomer
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