PPT: Heat Treatment | Engineering Materials - Mechanical Engineering PDF Download

 Page 1


Introduction 
. Heat Treatment 
•
Heat Treatment process is a series of operations 
involving the Heating and Cooling of  metals in the 
solid state.  
•
Its purpose is to change a mechanical property or 
combination of mechanical properties so that the metal 
will be more useful, serviceable, and safe for definite 
purpose. 
•
By heat treating, a metal can be made harder, stronger, 
and more resistant to impact, heat treatment can also 
make a metal softer and more ductile. 
Page 2


Introduction 
. Heat Treatment 
•
Heat Treatment process is a series of operations 
involving the Heating and Cooling of  metals in the 
solid state.  
•
Its purpose is to change a mechanical property or 
combination of mechanical properties so that the metal 
will be more useful, serviceable, and safe for definite 
purpose. 
•
By heat treating, a metal can be made harder, stronger, 
and more resistant to impact, heat treatment can also 
make a metal softer and more ductile. 
•
No one heat-treating operation can produce all of these 
characteristics. In fact, some properties are often 
improved at the expense of others. In being hardened, 
for example, a metal may become brittle.
Page 3


Introduction 
. Heat Treatment 
•
Heat Treatment process is a series of operations 
involving the Heating and Cooling of  metals in the 
solid state.  
•
Its purpose is to change a mechanical property or 
combination of mechanical properties so that the metal 
will be more useful, serviceable, and safe for definite 
purpose. 
•
By heat treating, a metal can be made harder, stronger, 
and more resistant to impact, heat treatment can also 
make a metal softer and more ductile. 
•
No one heat-treating operation can produce all of these 
characteristics. In fact, some properties are often 
improved at the expense of others. In being hardened, 
for example, a metal may become brittle.
The types of Heat Treatment:
1. Softening.    
2. Hardening.    
Page 4


Introduction 
. Heat Treatment 
•
Heat Treatment process is a series of operations 
involving the Heating and Cooling of  metals in the 
solid state.  
•
Its purpose is to change a mechanical property or 
combination of mechanical properties so that the metal 
will be more useful, serviceable, and safe for definite 
purpose. 
•
By heat treating, a metal can be made harder, stronger, 
and more resistant to impact, heat treatment can also 
make a metal softer and more ductile. 
•
No one heat-treating operation can produce all of these 
characteristics. In fact, some properties are often 
improved at the expense of others. In being hardened, 
for example, a metal may become brittle.
The types of Heat Treatment:
1. Softening.    
2. Hardening.    
1. Annealing
•
Annealing is the process for softening materials or to 
bring about required changes in properties, such as 
machinability, mechanical or electrical properties, or 
dimensional stability.
•
The annealing process consists of heating the steel to or 
near the critical temperature (temperature at which 
crystalline phase change occurs) to make it suitable for 
fabrication. 
•
A material can be annealed by heating it to a specific 
temperature and then letting the material slowly cool to 
room temperature in an oven.
Page 5


Introduction 
. Heat Treatment 
•
Heat Treatment process is a series of operations 
involving the Heating and Cooling of  metals in the 
solid state.  
•
Its purpose is to change a mechanical property or 
combination of mechanical properties so that the metal 
will be more useful, serviceable, and safe for definite 
purpose. 
•
By heat treating, a metal can be made harder, stronger, 
and more resistant to impact, heat treatment can also 
make a metal softer and more ductile. 
•
No one heat-treating operation can produce all of these 
characteristics. In fact, some properties are often 
improved at the expense of others. In being hardened, 
for example, a metal may become brittle.
The types of Heat Treatment:
1. Softening.    
2. Hardening.    
1. Annealing
•
Annealing is the process for softening materials or to 
bring about required changes in properties, such as 
machinability, mechanical or electrical properties, or 
dimensional stability.
•
The annealing process consists of heating the steel to or 
near the critical temperature (temperature at which 
crystalline phase change occurs) to make it suitable for 
fabrication. 
•
A material can be annealed by heating it to a specific 
temperature and then letting the material slowly cool to 
room temperature in an oven.
•
When an annealed part is allowed to cool in the 
furnace, it is called a "full anneal" heat treatment.