Heating Metal Affects Properties (One)

Heat can change metal's electrical, magnetic and structural properties, because the applications of metal are different from each other, different environments result in different qualities. For instance, in engineering applications, toughness is desired; in electrical applications, low electrical resistivity is important.

As we know, there are plenty of ways to heat metal which is often used to transform these properties. The temperature to which the metal is heated and the rate of cooling needs to be carefully controlled for achieving the desired outcome.

The Effect of Mental by Heat

The four most important ways that metals are transformed through heat as follows:

1、Electrical resistance

Electrical resistance is the measure of how strongly the metal impedes the passage of electrical current. When electrons pass through the metal, they scatter as they collide with the metallic structure. As the metal is heated, the electrons will absorb more energy and it will move faster than before. This leads to more scattering, thus increasing the amount of resistance. Thermometers actually use the change in electrical resistance in a piece of wire to measure temperature.

2、Thermal Expansion

The metal expands when heated. Length, surface area, and volume will increase with temperature. The scientific term for this is thermal expansion. The degree of thermal expansion varies with different types of metal. Thermal expansion occurs because heat increases the vibrations of the atoms in the metal. Accounting for thermal expansion is essential when designing metallic structures. An everyday example would be the design of household pipes, which must accommodate expansion and contraction as the season's change.

3、Structure

Metals are comprised of a symmetrical structure of atoms called as an allotrope. Heating the metal will displace atoms from their position and the displaced atoms form a new structure. This process is known as allotropic phase transformation. Allotropic phase transformation alters the hardness, strength, and ductility of the metal. The most important allotropic phase transformation is undergone by iron. When iron is heated past 1,674 degrees Fahrenheit it is able to absorb more carbon, which is an ingredient that will increase the hardness of any steel product

4、Magnetism

There are three metals with magnetic properties: iron, nickel, and cobalt. They are ferromagnetic metals. Heating these metals will reduce their magnetization to the point where magnetism is completely eradicated. The temperature at which this occurs is known as the Curie temperature. For a nickel, this temperature is 626 degrees Fahrenheit; for cobalt, it is 2,012 degrees Fahrenheit; and for Iron, it is 1,418 degrees Fahrenheit.

hot rolling process line