IMPORTANCE OF HOT WORKING PROCESS IN ENGINEERING

In this topic discuses about hot working and cold working process which is mostly important topic in manufacturing technology,  we are all known that metals flows as plasticity under action of applied forces . It may be described as hot working and cold working depending upon whether the metal is worked above re-crystallization temperature , the temperature at which new grains are formed in the metal is known as re crystallization temperature..

Hot working : The working of metal above re-crystallization temperature is called hot working.

Advantages  : 

1.  Porosity largely eliminated 
2. Grain structure of metal is refined 
3. Impurities of metal uniformly distributed 
4. Mechanical properties of metal are improved 

Disadvantages : 

1. Requires expensive tools 
2. Produce poor surface finish due to rapid oxidation and scale formation
3. Difficult maintain correct temperature range for working  .

Hot working processes : 

Hot rolling :  This is method of converting large sections into desired shapes. Ex : forming bars, sheets, angles,rails, I-beams,plates and other structural sections  

rails produced by hot rolling process

Sheets producing

Hot forging : It consist of  heating the metal to plastic state and then the pressure is applied to form in desired shape and size, The pressure is applied by hand tools, power hammer ,other forging machines.    

Bolt produced by hot forging

                                                                                            

Hot spinning : It consist of heating the metal to forging temperature and then forming into desired shape on spinning lathe, The circular section, which are symmetrical about the axis of rotation , are made by this process 

Hot spinning

Hot extrusion : It consist of pressing a metal inside a chamber to force it out by high pressure through an orifices which shaped provide desired form form of the finished part . The rods, tubes, circular shapes , flooring strips, and lead covered cables 

  

Hot drawing or cupping : It is mostly used for production of thick walled seam less tubes and cylinders with help of die and punch

Hot piercing : This process is used for the manufacturing of seam less tubs. In this operations the heated cylindrical billets of steel are passed between two conical shaped rolls operating in the same direction .A mandrel provided between the which assist in the piercing and controls the size of the holes as the billet is forced over it 

manufacturing seam less tubes

seam less tubes

piercing process