Rubber O-Ring Tensile Strength Testing - ASTM D1414

ASTM D1414 (D 1414) covers multiple properties of O-Rings. Part of the specification includes tension testing for determining the breaking force, tensile strength, and ultimate elongation of an o-ring. The tension test is intended to be performed on a universal testing machine (tensile testing machine). If you are going to perform this test, you should read the entire specification from ASTM. This is a quick summary to decide if this test is right for you, and to point out what equipment you need to perform the test.

 Here is a short video of the test: 

 

Test Procedure:
1. Lubricate the grip spools with oil (not required if doing step # 4)
2. Load the o-ring on both the upper and lower spools
3. Begin the test by separating the grips at a speed of 20 inches per minute
4. Rotate one spool one revolution per six inches of travel (not required if doing step # 1)
5. End the test after sample break (rupture)

Analysis obtained:
1. Breaking Force
2. Tensile Strength
3. Ultimate Elongation

Equipment required:
1. Universal testing machine (tensile testing machine) with these minimum specifications: (similar to those in ASTM D412)
A. Servo-controlled to keep a constant rate of speed during the test (+/- 2 inches/min)
B. At least 30 inches of crosshead travel or more for high elongation materials
C. Most small and common 1kN (225 pound) load capacity machines will work for the loads of the materials tested to this specification
D. All of our eXpert 2600 series dual column machines meet these requirements, and it is also common to use our single column eXpert 7601 XL with 53 inches of crosshead travel.

2. ASTM D1414 requires special grips. These grips have interchangeable spools with various diameters for a wide variety of o-rings. The spools rotate freely on a pin extending from the grip. If using the motorized version, the bottom grip and spool is connected to a small variable speed electric motor to enable rotation during the test to minimize stresses. Other more primitive and costly systems have been employed that generate rotation from the upward movement of the crosshead. However, the optional motorized version is easier to use and is usually less expensive.

ADMET Motorized ASTM D1414 O-Ring Fixture

3. If you don't want to use the motorized fixture, the specification allows you to lubricate the spools instead.  In this case, you would just use two of the upper grips.