Mechanical Engineering

Normalizing :- Normalizing is a heat treatment process used to refine the structure of the steel to improve machinability, tensile strength, structure of weld and to remove cold working strains etc.  Normalizing is often used for ferrous alloys that have been austenitized and then cooled in open air. Normalizing not only produces pearlite, but also bainite and sometimes martensite, which gives harder and stronger steel, but with less ductility than full annealing. The hardness obtained after normalizing depends on the steel dimension analysis and the cooling speed used.  Objectives of Normalizing :-  It produces a uniform structure It improves tensile, impact & yield strength It refines the internal structure to fine grains It removes the internal stress formed during previous operations It improves structures in welds It produces a harder and stronger steel then full annealing  It eliminates the carbide network at the grai...

Annealing:- Annealing  Process :- Annealing is a heat treatment process by which the properties of steel are enhanced to meet machinability requirements. In this process Hypoeutectoid steels (less than 0.83% carbon) are heated above upper critical temp., soaked and cooled slowly and  Hypereutecoid (above 0.83%) are heated above lower critical temp., soaked and allowed to cool slowly. Annealing  Process Steps: 1.Heat material into the asutenite region (i.e. above 1600F) – rule of thumb: hold   steel for one hour for each one inch of thickness 2.Slowly furnace cool the steel – DO NOT QUENCH 3.Key slow cooling allows the C to precipitate out so resulting structure is coarse  pearlite with excess ferrite 4.After annealing steel is quite soft and ductile The purpose of Annealing is : 1)Reduce hardness and brittleness 2)Alter microstructure for desired mechanical properties 3)Soften...

HEAT TREATMENT •           It is a continuous process of HEATING, HOLDING AT A PARTICULAR TEMPERATURE FOR SPECIFIC TIME AND COOLING AT A PREDETERMINED RATE of metals to change their physical and mechanical properties, without letting it change its  shape. . The most common application is metallurgical. Heat treatment  could be said to be a method for strengthening materials but could also be used to alter some mechanical properties such as improving formability, machining, etc. It is very important manufacturing processes that can not only help manufacturing process but can also improve product, its performance, and its characteristics in many ways. •           Engineering properties are modified by  heat treatment  processes so that structural components are able withstand specified operating conditions and have desired useful life. The properties of steel can...