ASTM D412

The ASTM D412 tension test is one of the most common procedures used to test the tensile properties of rubber and thermoplastic materials.  ASTM D412 Test Method A refers to procedures used to test Dumbbell and Straight Section Specimens while ATM D412 Test Method B refers to procedures used to test Cut Ring Specimens. The compatible ISO standard to ASTM D412 is ISO 48. United has a long history of helping our customers perform this test standard successfully, accurately and affordably.

Test Frame

When performing ASTM D412 special consideration should be given to how much travel your test frame will allow. Specifically, the standard calls for a minimum of 750 mm of travel and this distance would need to factor in the amount of space taken up by grips and fixtures, so in effect the overall height of the test frame would need to be taller than 750 mm, or 29.52 inches.

United’s 2.5kN DSTM single-column test frame is ideally suited to perform ASTM D412 since it provides more than enough travel. However, if you are incorporating an Environmental Chamber, or your expected capacity is more than 2.5kN (550 lbf.) one of United’s dual-column test frames, such as our DSTM 10kN would be our recommendation.

Environmental Chambers

While not required, there are customers that need to test samples at either very high or very low temperatures, in which case an Environmental Chamber would be required. If you are performing ASTM D412 and will be incorporating an Environmental Chamber into the test procedure, United offers a wide range of products which will help you meet the test specifications. United’s Environmental Chambers meet or exceed all the requirements set forth in the ASTM D412 standard and we offer a wide selection of specialized grips and fixtures to properly secure samples for testing. Environmental Chambers are mounted to a cart so they can be easily positioned in-between our dual-column test frames.

Grips & Fixtures

United offers a wide selection of grips when performing ASTM D412. Our Parallel Dogbone Grips for Type A specimens are rated to test up to 1000kN (220 lbf). For Type B Specimens United offers the “O” Ring Fixture which meets all specifications listed in the standard. When using an Environmental Chamber our recommendation would be to use our pneumatically controlled Hi/Low Temperature Positive Action Grips. Each grip meets or exceeds all the specifications set forth in the ASTM D412 standard.

Specimen Preparation

Improper sample preparation is one of the biggest causes of inconsistent test results when performing ASTM D412. United carries a large selection of sample die cutters which will ensure that your samples are cut the same each time. We offer sample cutters for both the Dumbbell, Straight Section Specimens and Cut Ring Specimens as specified in the ASTM D412 standard.

Extensometers

While not required in ASTM D412 the use of an extensometer is preferred. If you choose to use an extensometer it should conform to ASTM E83. All extensometers sold by United meet this specification and our highly trained sales staff can help you choose which extensomer will work best for your specific application.

Test Procedure & Calculations

United’s DragonFly UTS software along with one of our Universal Test Machines is fully capable of performing the ASTM D412 test procedure. Each UTM we sell includes the test frame, loadcell, Windows PC, software, and the pre-written test procedure. Test speed, calculations (Stress at User-Specified Extension or Elongation, Tensile Yield Stress, Tensile Yield Strain, Tensile Strength at Rupture, Elongation at Rupture) custom reports, and many other features are available immediately.

Conclusion

United has done virtually all the work for our customers when it comes to performing the ASTM D412 test procedure. All customers need to do is determine which sample type they will be testing so we can choose the proper test frame and grips.

http://www.astm.org/cgi-bin/resolver.cgi?

D412-16

Citation – ASTM D412-16, Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers—Tension, ASTM International, West Conshohocken, PA, 2016, www.astm.org