Induction hardening is a process of hardening which is used to harden the particular or part to be required to be hardened. In this they used the faraday lows of induction.

1. BY
JEEVAN B M
1ST SEM, AUTOMOTIVE ELECTRONICS
P151905
SJCE,MYSORE
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2. Contents
• Introduction
• history
• Tempering
• Methods of hardening
• Applications of hardening
• References
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3. INTRODUCTION
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• Hardening is process in which steel is heated to a temperature
above the critical point, held at this temperature and quenched in
water, oil or molten salt bath
• Types of hardening are quench hardening, work hardening,
precipitation hardening, surface hardening
• Types of surface hardening are flame hardening, induction
hardening, carburizing, cyaniding, nitriding, carbonitriding.

4. Con..
• Induction hardening is a form of heat treatment in which a metal
part is heated by induction heating and then quenched
• Material is heated by passing the current that generates alternating
magnetic field resistance leads to heating of the metal
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5. 5 History
• The basis of all induction heating systems was discovered in 1831
by Michael Faraday.
• Faraday proved that by winding two coils possible to create a
momentary electromotive force in the second winding by switching
the electric current in the first winding on and off.
• Using this principle invented electrical generators and electric motors,
which are variants of the same thing)

6. • But the disadvantages of these system is they generate a heat
• To avoid this heat generate used laminated cores and other methods
to minimize the effects
• Engineers at Midvale Steel and The Ohio Crankshaft Company
drew on this knowledge to develop the first surface hardening
induction heating systems using motor generators.
• Modern day induction heating units utilize the latest in
semiconductor technology and digital control systems to develop a
range of powers from 1 kW to many megawatts
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7. Basic principle
• All metals conduct electricity, while offering resistance to the flow
of this electricity
• The resistance to this flow of current causes losses in power that
show up in the form of heat
• This is because, according to the law of conservation of energy
• The losses produced by resistance are based upon the basic electrical
formula:
P=I^2R
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8. Practical way of heating
 AC current through a copper coil, and the part to be heated (the
work piece) is placed inside the inductor
 As soon as AC is supplied work piece enters the magnetic field,
circulating eddy currents are induced within the part
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9.  these eddy currents flow against the electrical resistivity of the metal,
generating precise and localized heat
 This heating occurs with both magnetic and non-magnetic parts, and is
often referred to as the "Joule effect“
 Secondarily, additional heat is produced within magnetic parts through
hysteresis – internal friction that is created when magnetic parts pass
through the inductor
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continue

10. Factors to consider
• Characteristics of work piece
o METAL OR PLASTIC
o MAGNETIC OR NON-MAGNETIC
o RESISTIVITY
• Inductor(coil) design
• Power supply
• Degree of temperature range is required
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11. Methods of induction hardening
Single shot hardening
• Single-shot hardening means the complete hardening zone is first heated
and then quenched
• hardening can be achieved with a multi-turn coil that encircles the entire
hardening zone
• Single shot is often used in cases where no other method will achieve the
desired result
• Drawback--The coil design can be an extremely complex and involved
process
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12. Traverse hardening
• In traverse hardening systems the work piece is passed through the
induction coil progressively and a following quench spray or ring is
utilised
• The component is fed through a ring type inductor which normally
features a single turn
• Traverse hardening is used extensively in the production of shaft
type components such as axle shafts, excavator bucket pins, steering
components, power tool shafts and drive shafts
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13. Advantages
 Specific limited local hardening is possible
 The distortion can be kept very small
 The hardening times will be shorten
 Heating Process Controllable and Repeatable
 Improved Product Quality
 more production rate
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14. Application
 Industrial application
 Medical application
 Work piece with more length like axels shafts can be operated
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15. Disadvantages
 High capital investment is need
 Each shape of a components requires inductor to be designed for it,
this comes in difficult in induction hardening
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16. References
 Induction hardening a quick guide to methods and coil
 Effect of induction hardening on high carbon steel forgings-subir danda
 Induction heating-Qadri Mayaleh & AbdelRahman Abbass
 http://www.gh-ia.com/induction_heating.html
 http://www.uihm.com/en/Induction-Technology/What-is-Induction-Heating-
and-induction-Principle-15.html#.VlFazPmqpBc
 http://www.efd-
induction.com/~/media/Articles/InductionHardening_MethodsCoils.ashx
 http://ezinearticles.com/?Induction-Hardening&id=4803616
 http://www.uihm.com/english/What-is-Induction-Hardening-12-77-
340.html#.VlGkgvmqpBc
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