| Actual Weight | (english) The customer buys by the actual (scale) weight of the steel. The theoretical weight is used in estimating, however, it is not to be used for billing. |
| ACTUATOR | (english) A device for converting hydraulic energy into mechanical energy, i.e., a motor or cylinder. |
| Acute Angle | (english) An angle that is less than 90 degrees. |
| ADAPTER | (english) A mechanical device used to align the shaft of an electric motor (or other rotary device) with the shaft of a hydraulic pump to maintain radial and parallel shaft alignment. |
| Adapters | (english) Steel segments that are bolted to the reel mandrel to increase their diameter so that large (24" ID) coils can be run. |
| Adapti Investment Casting Process | (english) A lost wax process employing one of three methods; centrifugal, vacuum or gravity-pouring casting. |
| Addendum | (english) That portion of a gear tooth that extends from the pitch circle to the outside diameter. |
| Addition Agent | (english) 1) Any material added to a charge of molten metal in bath or ladle to bring alloy to specifications, 2) reagent added to plating bath. |
| Adeline Steelmaking Process | (english) Method of producing a precision casting of steel or steel alloys using aluminolthermic process and lost wax, followed by centrifugal action. |
| Aecm, Ae1, and Ae3 | (english) Equilibrium transformation temperatures in steel. |