ASTM A938 | Metals | Torsional Properties
ASTM A938 is a testing standard that describes the torsion (or twist) testing procedures of metallic wire. The results of torsion tests can be used to assess wire ductility under torsional loading.
The torsion testing machine should have chuck jaws that will remain coaxial during the test. One of the chucks should be easily displaceable in the direction of the wire axis. The wire should be twisted only along the test length, and not at the point of clamping. The torsion machine’s controller should be able to count the number of revolutions during the test. We recommend eXpert 9000 series with MTESTQuattro controller and software to run ASTM A938.
Prior to conducting ASTM A938, it is important to read the entire specification in the relevant ASTM publication.
ASTM A938 | Metals | Torsional Properties
- Straighten the test sample wire prior to the test. Measure the wire diameter.
- Mount the sample in the torsion grips. The recommended test length or the distance between the chuck heads is 8 in (203 mm). Make sure the specimen remains as straight as possible during testing. This can be accomplished by applying a small tensile force to the specimen prior to starting the torsion test.
- Start the test by rotating one clamp at a constant speed. Refer to the standard for recommended twisting speeds.
- Stop test when the sample breaks.
- Total Turns to Fracture
ASTM A938 | Metals | Torsional Properties
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