Impact Tests
:
COMPOSITION AND PROPERTIES OF STEEL
:
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.