Impact Tests

: The Working Of Steel

Impact tests are of considerable importance as an indication of

how a metal will perform under shock. Some engineers think that

the tensile test, which is one made under slow loading, should

therefore be supplemented by another showing what will happen if

the load is applied almost instantaneously. This test, however, has

not been standardized, and depends to a considerable extent upon

the type of machine, but more especially the size of the specimen

and the way it is nicked. The machine is generally a swinging

heavy pendulum. It falls a certain height, strikes the sample at

the lowest point, and swings on past. The difference between the

downward and upward swing is a measure of the energy it took to

break the test piece.