Volume 2, Issue 5 (September 1974)
Axial Alignment Fixtures for Tension Tests of Threaded Specimens
A fixture of simple design is described that is capable of providing very low eccentricity of loading in tension tests of threaded specimens. This fixture is suitable for use with the Method for Screening Tests Using Sharply Notched Cylindrical Specimens proposed by ASTM Committee E-24 on Fracture Testing of Metals. A special ½-in.-diameter (12.7-mm-diameter) evaluation specimen and associated procedure is described which is useful for determining the maximum bending that might be encountered in routine use of the fixture. The results obtained using this technique show that the maximum bending stress can be reliably limited to less than five percent of the average axial stress for an axial stress equal to or greater than 30 ksi (207 MPa) on the evaluation specimen. This evaluation technique is also suitable for verification of the satisfactory performance of other types of fixtures intended for use in the tension testing of sharply notched cylindrical specimens.