What is Hot working in Manufacturing ?

Hot working is the initial step in mechanical working of most metals and alloys. Hot working combines the working and annealing processes by deforming metal above the recrystallisation temperature at which new grains are formed. Since most metals and alloys have relatively high recrystallisation temperatures, they must be worked at high temperatures. Each metal, of course, has a characteristic hot-working temperature range over which hot working may be performed. The upper limit of working temperature depends on metal composition, prior deformation, and impurities within the metal. Obviously, the upper limit for working must be somewhat below the melting or burning point. The finishing temperature , however, is usually just above the minimum recrystallisation temperature at which reheating is desired before further hot working.

In addition to mere change of shape, hot working has profound effects on metal characteristics or properties. The changes in structure from hot working improve mechanical properties such as ductility, toughness, elongation percentage, reduction of area percentage, and resistance to shock and vibration.

However, there are certain disadvantages to hot working.

The principal methods of hot working are as follows :

1. Rolling

2. Piercing

3. Drawing

4. Spinning

5. Extruding

6. Forging

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Mechinopedia For Mechanical Engineers

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