Determining the nil ductility temperature of steel using ASTM E208 involves impacting a series of “cracked” samples, to deflection levels that ensure yield conditions at the crack location, at different temperatures so as to determine the highest temperature (usually sub-zero) at which the sample fractures. Below this temperature the sample steel consistently fractures but does not fracture above this temperature.

Drop Weight Tear Tests (DWTT) by ASTM E436 have a very similar objective to nil ductility tests, however, the larger 12 by 3 x t inch specimen provides information about the relative amounts of ductile and cleavage/brittle features present on the fracture surface.

Dynamic Tear (DT) Testing to ASTM E604 measures the energy absorbed during the fracture process of a “pre-cracked” specimen. The test objective is very similar to the tests outlined above, however, the measurement of energy eliminates some of the subjectivity of some of the other tests and allows acceptance levels to be specified by the end users for steels used in critical applications such as pressure vessels.