| Ac1 | (english) The temperature at which austenite begins to form on heating. |
| Ac3 | (english) In hypoeutectoid steel, the temperature at which transformation of ferrite into austenite is completed upon heating. |
| Accm | (english) In hypereutectoid steel, the temperature at which cementite goes into complete solution with austenite. |
| Accordion Reed Steel | (english) Hardened, tempered, polished and blued or yellow flat steel with dressed edges. Carbon content about 1.00. Material has to possess good flatness, uniform hardness and high elasticity. |
| Acid | (english) 1) A solution or liquid with a pH less than 7, 2) term applied to slags, refractors, and minerals containing a high percentage of silica. |
| 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 | (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. |
| 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. |
| Aecm, Ae1, and Ae3 | (english) Equilibrium transformation temperatures in steel. |
| 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. |