This test method covers the dynamic tear (DT) test using specimens that are 3⁄16 in. to 5⁄8 in. (5 mm to 16 mm) inclusive in thickness.

This test method is applicable to materials with a minimum thickness of 3⁄16 in. (5 mm).

The pressed-knife procedure described for sharpening the notch tip generally limits this test method to materials with a hardness level less than 36 HRC.

The DT energy value is a measure of resistance to rapid progressive fracturing. In a number of applications, the enhanced resistance that may develop during about one plate thickness of crack extension from a sharp notch is of major interest. In the test method, a sufficiently long fracture path is provided so that the results serve as a measure of this property. Fracture surfaces of nonaustenitic steels tested in their temperature transition region have areas that appear bright and

areas that appear dull. The bright, faceted appearing areas are termed “cleavage” fracture, and the dull appearing areas are termed “shear” fracture after their respective mode of fracture on a micro scale.