Heat Flashcards
Hardening
Hardening is a metallurgical metalworking process used to increase the hardness of a metal. The hardness of a metal is directly proportional to the uniaxial yield stress at the location of the imposed strain. A harder metal will have a higher resistance to plastic deformation than a less hard metal.
Tempering
Tempering, in metallurgy, process of improving the characteristics of a metal, especially steel, by heating it to a high temperature, though below the melting point, then cooling it, usually in air. The process has the effect of toughening by lessening brittleness and reducing internal stresses.
Annealing
In metallurgy and materials science, annealing is a heat treatment that alters the physical and sometimes chemical properties of a material to increase its ductility and reduce its hardness, making it more workable.
Normalising
Normalising involves heating a material to an elevated temperature and then allowing it to cool back to room temperature by exposing it to room temperature air after it is heated. This heating and slow cooling alters the microstructure of the metal which in turn reduces its hardness and increases its ductility.
Conduction
Conduction is the way in which energy is transferred (through heating by contact) from a hot body to a cooler one (or from the hot part of an object to a cooler part).
Convection
When a fluid, such as air or a liquid, is heated and then travels away from the source, it carries the thermal energy along. This type of heat transfer is called convection. The fluid above a hot surface expands, becomes less dense, and rises.
Radiation
Heat transfer by thermal radiation between two bodies. Unlike conduction and convection, heat transfer by thermal radiation does not necessarily need a material medium for the energy transfer. … In the case of a gas (e.g., air), energy can be slightly absorbed or reflected by air molecules and the balance is transmitted.
