| Acid Brittleness (Pickling Brittleness) | (english) Brittleness resulting from pickling steel in acid; hydrogen, formed by the interaction between iron and acid, is partially absorbed by the metal, causing acid brittleness. |
| Acid Process 1 | (english) A process of making steel, either Bessemer, open-hearth or electric, in which the furnace is lined with a siliceous refractory and for which low phosphorus pig iron is required as this element is not removed. |
| Acid Process 2 | (english) A steel making method using an acid refractory-lined (usually silica) furnace. Neither sulfur or phosphorus is removed. |
| Acid Steel | (english) Steel melted in a furnace with an acid bottom and lining and under a slag containing an excess of an acid substance such as silica. |
| Acid-Brittleness | (english) Brittleness resulting from pickling steel in acid; hydrogen, formed by the interaction between iron and acid, is partially absorbed by the metal, causing acid brittleness. |
| Acid-Process | (english) A process of making steel, either Bessemer, open-hearth or electric, in which the furnace is lined with a siliceous refractory and for which low phosphorus pig iron is required as this element is not removed. |
| Activation | (english) The changing of the passive surface of a metal to a chemically active state. Contrast with passivation. |
| Addendum | (english) That portion of a gear tooth that extends from the pitch circle to the outside diameter. |
| 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. |
| Age Hardening | (english) Hardening by aging, usually after rapid cooling or cold working. The term as applied to soft, or low carbon steels, relates to a wide variety of commercially important, slow, gradual changes that take place in properties of steels after the final treatment. These changes, which bring about a condition of increased hardness, elastic limit, and tensile strength with a consequent loss in ductility, occur during the period in which the steel is at normal temperatures. |