ASTM D412 – 06a Standard Test Methods
The ASTM D412 – 06a test methods include the procedures to measure the tensile properties of the vulcanized thermostat rubbers and thermoplastic elastomers. The standard cannot be used for low elongation materials and includes Test Method A for dumbbell and straight section specimens and Test Method B for cut ring specimens. The test result of both methods is not identical.
The test method determines the tensile properties by examining the pieces taken from a sample material. The sample preparation and testing are part of the testing process. The samples could be dumbbells, straight or ring-shaped pieces of cross-sectional area. The tensile stress is measured at a given elongations, yield point, tensile strength which are based on the cross-sectional area of the test sample. The tensile measurement is performed when the unstressed sample is extended and retracted.
The test method covers the materials and products that can withstand the tensile forces for proper performance in certain applications. The tensile properties are evaluated however these properties does not completely relates to the end performance requirement in real use. The temperature and rate of extension need to be controlled for a better result. The tensile set indicates the partially permanent or partially recoverable deformation, thus, the period of extension and recovery requires to be controlled to get the results that can be compared.
ASTM D412 – 15a – Updated Standard Method
The Tensile Tester evaluates the tensile strength of the materials and is based on the constant rate of transverse principle. The instrument is used to test the tensile strength of the rubber, plastic, metal, steel, ferrous alloys, and aluminum.
The ASTM D412 – 06a identifies that D is the miscellaneous materials, 412 indicates sequential number, 06 is the year of adoption, and a indicates subsequent revision. The ASTM D412 – 06a is superseded and ASTM D412 – 15a standard is updated test method applied for measuring the tensile forces.
The ASTM D624 – Standard Test Method is used to measure the resistance to tearing action, which is a special type of rupture propagate in vulcanized rubber and thermoplastic elastomer. The stress induced anisotropy or mechanical fiber, strain rate, stress distribution and size of test piece affects the tear strength.
The tear testing significance is different for individual application. ASTM D624 specification is applied to measure the tear strength of thermostat rubbers, silicones, and thermoplastic elastomers. The force required to develop a tear in the material is determined using the test method. Multiple shapes of samples are tested using the tensile testing machine.