ASTM D412-16 | Mecmesin

ASTM D412 is a test standard for testing the tensile stress-strain properties of thermoset rubbers and thermoplastic elastomers. The standard is divided into two test methods. Method A is used for evaluating the tension properties of dumbbell type samples and Method B covers procedures to evaluate the tension properties of flat ring type samples. Calculations derived from ASTM D412 include tensile set, tensile stress at a given elongation, tensile strength, yield point and ultimate elongation (at break).

Before conducting ASTM D412, it is important to read the entire specification. Standards can be obtained from appropriate standard authorities.

This test standard is similar to ISO 37.

Method

Principle

Standard test pieces, either 'dog-bone' dumbbells, rings, or straight test pieces, of uniform cross-sectional area, are stretched in a tensile testing machine at a constant rate. Readings of force and elongation are taken as required during the uninterrupted stretching of the test piece and when it breaks. Measurement of 'tensile set' is also included.

Apparatus

Tensile tester

The tensile testing machine, Calibrated IAW ASTM E4.
Speed control capable of speeds between 1 mm/min (+/- 0.2 mm/min) up to 500 mm/min (+/- 50 mm/min).

Any of the OmniTest and MultiTest-dV range are suitable, as they support extensometers.

Extensometer

An extensometer is preferentially used, enabling accurate elongation measurement of the test piece.

The Mecmesin MLTE extensometer range is suitable for extension measurements.

Test pieces

Five of test pieces are required, i.e. dumbbell-shaped types A, B, C, D, E, F; straight test pieces; or ring-shaped types 1 and 2.

Specimen cutters

The shape and dimensions of the die for preparing dumbbell specimens shall conform to the data in the test standard..
Sample presses are also available either manual or pneumatic, the testing machine may also be used to apply the force to cut the sample if it has sufficient capacity.