What is metal heat treatment?

Heat treatment is the process of heating metal without letting it reach its molten, or melting, stage, and then cooling the metal in a controlled way to select desired mechanical properties. Heat treatment is used to either make metal stronger or more malleable, more resistant to abrasion or more ductile.

What is heat treatment of metals PDF?

Heat treatment consists of heating the metal near or above its critical temperature, held for a particular time at that finally cooling the metal in some medium which may be air, water, brine, or molten salts.

Why is metal heat treated?

Heat treatment is a controlled process used to alter the microstructure of metals and alloys such as steel and aluminium to impart properties which benefit the working life of a component, for example increased surface hardness, temperature resistance, ductility and strength.

What are the different types of heat treatment?

There are five basic heat-treating processes: hardening, tempering, annealing, normalizing, and case hardening. Although each of these processes brings about different results in metal, all of them involve three basic steps: heating, soaking, and cooling (Fig. 1.45).

Why are metals heat treated?

The most common reasons that metals undergo heat treatment are to improve their strength, hardness, toughness, ductility, and corrosion resistance. In this process, the metal is heated above its upper critical temperature to change its microstructure. Afterward, the metal is slow-cooled.

What is the heat treatment process for steel?

The normal processes used for the heat treatment of steels are (i) annealing, (ii) normalizing, (iii) hardening, and (iv) tempering. Annealing is a heat treatment process which involves heating and cooling. The process is normally used for the softening of steel.

Which one is the heat treatment process?

Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve the desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching.

Why is metal heat treatment necessary?

Heat treating can improve wear resistance by hardening the material. Metals (including steel, titanium, inconel, and some copper alloys) can be hardened either on the surface (case hardening) or all the way through (through hardening), to make the material stronger, tougher, more durable and more resistant to wear.