The following table lists the related ASTM test standard and describes the most commonly referenced physical property characteristics of rubber and rubber products:
|
Feature |
ASTM
Test Std |
Description |
|
Hardness |
D2240 |
Resistance to compression or indentation measured according to the Shore A Durometer scale; a.k.a. "durometer". |
|
Tensile Strength |
D412 |
Pull-force per cross-section area (measured in PSI or MPa) required to rupture the material. |
|
Modulus |
D412 |
Pull-force per cross-section area (measured in PSI or MPa) required to elongate material to a defined percentage of original length. |
|
Elongation |
D412 |
Ultimate elongation, stated as a percentage of original length, required to rupture material; a.k.a. "ultimate elongation" |
|
Compression Set |
D395 |
Resistance to conformance to compression or deformation caused by compression. Measured as a percent material fails to return to original thickness after subjected to compression for a period of time. |
|
Abrasion Resistance |
|
Resistance to surface wear and tear resulting from friction and dynamic contact with other surfaces; an important feature in many products like tires, belts, and o-rings. |
|
Tear Resistance |
|
Pull-force required to tear a defined section of rubber a certain distance from a slightly knicked edge; sometimes measured both with and against the "grain" or "machine direction" of calendered or extruded materials. |
|
Flame Resistance |
|
Pass or fail test of material subjected to proscribed contact with flame. Pass indicates the material did not ignite or carry a flame itself, once removed from external source. |
|
Heat Resistance |
D573 |
Measures degree of loss in mechanical properties after subjection to defined time and temperature conditions. |
|
Low Temperature Resistance |
D2173 |
Tests for brittleness or crystallization of material after subjection to defined time and temperature conditions; usually stated as 'pass' or 'fail', indicating whether or not the material remained flexible at the stated temperature. |
|
Ozone Resistance |
D1171 |
Tests for appearance of surface cracks, crazing, or checks after subjection to proscribed levels of ozone (using a laboratory chamber) and other conditions (time, temperature, relaxed or elongated state). |
|
Fluid Resistance |
D471 |
Measures volume change due to swelling or shrinking caused by subjection to specified fluids, times, and temperatures. Commonly, ASTM #1, 2, and 3 Oils plus ASTM Fuels A, B, and C are used in these tests, covering a wide range of aniline points (oils) and aromatic content (fuels), which are good broad indicators of an elastomer's resistance to other oils and fuels. |
|
Specific Gravity |
N/A |
Measures density as ratio of mass (weight) to an equal volume of water (at 4°C / 34°F). Since one cubic foot of distilled water weighs 64.2 pounds, then the weight of any volume of material can be calculated as ð [Cubic Feet x 64.2 x Specific Gravity], [Cubic Inches x 0.03715 x Specific Gravity], or [Liters x Specific Gravity] for total weight in Kilograms (Kg), since water weighs 1 kg per liter. Example: 20 lineal feet x 36 inch wide x 1/4 inch thick material, with a specific gravity = 1.15 ð 0.25" x 36" x 240" (20 LF) x .03715 LB/Cu.In. (water) x 1.15 specific gravity = 92 lbs. |
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