Vertical Drop-Weight Machine for Conducting Drop-Weight Ndt, Drop-Weight Tear, and Dynamic Tear Tests

摘要

Methods for determining the fracture resistance of steels using the Drop-Weight Nil-Ductility Transition (DWT-NDT) Test, the Drop-Weight Tear Test (DWTT), and the 5/8-in. Dynamic Tear (DT) test, all by the use of a single vertical impact machine, are described. A vertical impact machine is useful when a limited number of tests are to be conducted, and when cost is an important aspect for determining equipment type. The machine described is of 2000 ft-lb capacity, and two methods for the determination of dynamic tear energy are described. One method employs an oscilloscope trace of the hammer load during the fracture process, and the other method uses the residual kinetic energy of the hammer to compress lead bars. A vertical impact machine is the standard tool (ASTM Standard E208) for conducting the DWT-NDT, and it can be readily modified to conduct the DWTT and the 5/8-in. DT tests. (Author)