• Age hardening
• The changes that takes place in a steel after its final treatment at normal temperatures. The changes are slow and gradual and increase the hardness, elastic limit and tensile strength of the steel. It also results in a loss of ductility.

• Aging
• Spontaneous changes occurring in the physical as well as mechanical properties of low carbon steel. If steel is subjected to elevated temperatures the aging process will be accelerated.

• Air cooling
• The method of letting a metal cool down in open air after the process of annealing or other heat treatment. When air cooling is used, no stacking is involved.

• Air hardening steel
• Steel that contains enough carbon and other alloying elements that allow it to be hardened in temperatures above its transformation range. This creates a martensitic steel structure without the steel going through the process of quenching.

• AISI
• The American Iron and Steel Institute that is a North American trade association. It has 50 member companies as well as 100 associate members representing America, Canada and Mexico.

• AL
• Chemical symbol for aluminum. In the steelmaking process, aluminum is used as an alloying agent to efficiently deoxidize steel, restricting grain growth and it is an alloying element in nitriding steel.

• Alloying element
• Metallic elements added during the steel production process to enhance particular properties of the steel. The most common elements used in stainless steel are molybdenum, chromium and nickel.

• Alloy steel
• Refers to steel that has a substantial content of elements other than carbon and the generally accepted levels of manganese, sulfur, silicon and phosphor. These elements are added to raise the strength, hardness or chemical resistance of the steel.

• Alloy Surcharge
• A supplementary charge added to the selling price of steel in order to offset price increases in raw materials used in the manufacture process such as nickel, chromium and molybdenum. The surcharge is calculated using raw material prices on certain accepted exchanges like the London Metals Exchange.

• Annealing
• A process wherein the steel is heated to a temperature and after this temperature is maintained for a certain time, the steel is cooled at a suitable rate. This is done in order for the steel to reach the desired microstructure and properties as well as to reduce the hardness of the steel. The heating is usually done to over 1, 900 degrees Fahrenheit, followed by a rapid cooling process.

• Anodic protection
• A method of corrosion control that promotes passivity by polarizing the steel to a more oxidizing potential.

• Argon-oxygen decarburization (AOD)
• The process as well as the vessel used to further refine stainless steel by lowering the carbon content. A mixture of nitrogen, oxygen and argon as well as some other gasses are blown into the metal and this reacts with the carbon oxygen to create an ideal mixture of steel and slag and allows impurities to be removed. The AOD is very similar to the electric arc furnace but operates at lower temperatures and also has a shorter operating period.

• Austenite
• A non-magnetic, solid metallic solution of iron and carbon present in steel above 1, 333 degrees Fahrenheit.

• Austenitic steel
• This is an alloy steel with primarily an austenitic structure at room temperature. It is a non-magnetic stainless steel with a chromium content of between 16 to 30 percent and a nickel content of 4 to 28 percent. Austenitic steel has excellent ductility, formability, is very resistant to corrosion and has good weldability. It is the stainless steel grade that is most widely used.

• Automatic gauge control
• The hydraulic roll force system used by steelmakers to automatically calculate and adjust the thickness of the steel sheet while it is moving through the mill.