Key Metallurgy Definitions
Some significant transformations are induced in steels, such as annealing, generally performed to achieve a smaller grain size and, consequently, improve metal properties.
Anisotropy
Anisotropy is the property of a material according to which certain physical properties, such as elasticity, thermal conductivity, velocity of propagation, and light, vary depending on the direction in which they are examined.
Alloy
An alloy is a system consisting of several elements, of which at least one is a metal, retaining metallic properties at room temperature.
Overheated Steel
Overheated steel results when the heat treatment temperature or heating time is excessive, producing a large grain size.
Effervescent Steels
In effervescent steels, only a small fraction of oxygen has been removed during the solidification process, leaving an outer layer or rim relatively free of carbon. This means the center of the ingot has a higher carbon content than the outside. This surface with an extremely low carbon portion is very ductile, possesses excellent surface characteristics, and is very good for cold forming.
Calmed Steels
Calmed steels are the opposite of effervescent steels. A large amount of oxygen has been extracted, resulting in a steel that is relatively free of carbon. Calmed steels are useful when serious shaping techniques are needed, but they always require heat treatment to complete the manufacturing technique of forming.
Steel
Steel is an alloy of iron and carbon, where carbon does not exceed 2.1% by weight. The composition of the alloy normally reaches rates between 0.2% and 0.3% carbon in common steels.
Pig Iron
Pig iron is an intermediate product of the iron industry, obtained in the blast furnace from iron ores.
Electron Affinity
Electron affinity, A, is the energy exchanged in the process by which a neutral atom X, in a gaseous state and in its ground electronic state, receives an electron and becomes a mononegative ion X–, also in the gaseous state and in its electronic ground state.
Bainite
Bainite is a mixture of ferrite and cementite obtained from the isothermal transformation of austenite, starting with the formation of ferrite.
Bronze
Bronze is the name given to a number of metal alloys which are based on copper combined with 3 to 20% of tin.
Composites
Composites, also called hybrid materials, are a set of materials primarily resulting from integrating two or more different materials with distinct properties to create a new material with enhanced characteristics compared to the individual components.
Grain Growth
Grain growth occurs at the end of recrystallization. If heating is continued above the recrystallization temperature, the grain structure continues to grow with increasing temperature.
Steel Product Categories (UNE)
- Iron
- Steel
- Thermoalloys
- Special Alloys
Carburization
Carburization is a process involving the combination of carbon and iron to form steel or increase the carbon content of steel.
Note on Heat Treatment Stages
When the crystallization process ends, the grain size is large. However, if the temperature is kept increasing above the recrystallization temperature, grain growth continues. Cooling follows this stage.
Frenkel Defect
A Frenkel defect is the combination of an interstitial atom and the vacancy (hole) left after the atom’s jump.
Schottky Effect
The Schottky effect is the strengthening of the thermionic emission of a conductor as a result of an electric field at the conductor surface.
Dislocation
A dislocation is a line defect consisting of a local disturbance of the lattice. Types include:
- Edge
- Screw
- Mixed