Heat Treatment
2
Heat treatment Heat treatment is the process in which a metal is simultaneously heated and cooled in control manner to achieve the desired properties. There are two major categories in which heat treatment categorizes: 1. Heat treatment of ferrous metals 2. Heat treatment of non- ferrous metals Heat treatment of ferrous metals: It consist of three steps: 1. Heat 2. Cool 3. Temper Heat treatment of non-ferrous metals: 1. Heat 2. Cool 3. Age In the older times, the blacksmith, heat the metal in coal to form carbon steel, then hammer it then heat in coal again and then cool it in the water. In this way we can get an idea that by changing and controlling the heat treatment process we can change the metal properties. Soft, hard, ductile, brittle, are the properties which can be controlled by heat treatments. Spring making: Lets take an example of heat treatment controlled processes to make a spring used in shock absorbers, etc. first the metal sheet from which the spring is to be made, is heat treated before shaping it into spring. The following processes carried out on spring metal sheet, in order to induce high elasticity in the metal: 1. Heating at 1600 degrees Fahrenheit. 2. Quenching in oil 3. Tempering in furnace. Preparation steps done after casting for heat treating the metals: The following are the steps carried out when the castings are going to be heat treated: Washing: the castings are first washed in detergents, and grease breaking solutions to remove lubrications and dirt.
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Transcript of Heat Treatment
Heat treatment
Heat treatment is the process in which a metal is simultaneously heated and cooled in control manner to achieve the desired properties. There are two major categories in which heat treatment categorizes:
1. Heat treatment of ferrous metals2. Heat treatment of non- ferrous metals
Heat treatment of ferrous metals:
It consist of three steps:
1. Heat 2. Cool3. Temper
Heat treatment of non-ferrous metals:
1. Heat 2. Cool3. Age
In the older times, the blacksmith, heat the metal in coal to form carbon steel, then hammer it then heat in coal again and then cool it in the water. In this way we can get an idea that by changing and controlling the heat treatment process we can change the metal properties. Soft, hard, ductile, brittle, are the properties which can be controlled by heat treatments.
Spring making:
Lets take an example of heat treatment controlled processes to make a spring used in shock absorbers, etc. first the metal sheet from which the spring is to be made, is heat treated before shaping it into spring. The following processes carried out on spring metal sheet, in order to induce high elasticity in the metal:
1. Heating at 1600 degrees Fahrenheit.2. Quenching in oil3. Tempering in furnace.
Preparation steps done after casting for heat treating the metals:
The following are the steps carried out when the castings are going to be heat treated:
Washing: the castings are first washed in detergents, and grease breaking solutions to remove lubrications and dirt.
Racking: it is actually a hanging process in which the castings are clipped in metal frame in order to ease the handling.
Fixturing: it is a clamping process which is used for those castings which cannot be racked.
Heating: the fixture castings are then heated at elevated temperatures in furnaces like box, vacuum, and pit- type.
Cooling: after heating in the furnace the castings are then quenched in oil, salt or water
Washing: the castings are then again washed to remove any residues, dirt or oil remains.
Tempering: the castings are then tempered in heating furnaces
Testing or inspection: the castings are finally tested for hardness, tensile strength and fatigue strength, etc .
