The
toughness of a
steel is often measured by a Charpy impact test as the energy
absorbed at a given temperature. Depending on the application a
different specification of energy level required at a given
temperature will be made by the customer, for example for some
plate
steels to be used in bridges 27 J (equivalent to 20 ft.lb.) at
-40 °C is required. A ductile-brittle transition curve can
also be determined.
For high performance steels, e.g. aircraft undercarriages, a
KIc
value may be used to quantify the toughness.
The main contributions to the toughness of a steel come from:
All of these aspects need to be taken into account when selecting
or designing a steel for a given application.
