1. NAME : MANIKUMAR B

2. CASE HARDENIG PROCESS
NITRIDING
CARBURISING
CYNIDING
CARBONITRIDING

3. Nitriding process is introducing nitrogen
atom to obtain hard surface of steel
component
To use medium carbon steel & alloy steel (
Al, Cr, Mo)
 use of ammonia gas

4. To heat 450 to 550 c heat and spread
ammonia gas
20 to 80 hours
Ti me & tempreature to deside surface
hardness & depth

6. Extream hard surface
Increase wear resistance
Endurance limit
No dimension change
No distortion

7. Guide way
Air craft engine cylinder
Crank shaft & pin
Valve seat & gear
journals

8.  Solid state hardening process
 This is the process of increase carbon
content on the surface of workpice
 Materials used ( charcoal , barium carbonate ,
leather scraps)
 Carbon rich material evenly placed
 To heat the air tight furnace 850 to 950 c
 Work piece + carbon rich material heat and
react
 Outer surface of material with increace
carbon content

10. Increase corrosion resistance
Increase hardness
Improve machinability
Increase wear resistance

11. Automotive
Aerospace industries

12. In cyaniding carbon and nitrogen are
introduced into the surface of steel by
heating it to a suitable tempreature .
And holding it in contact with molten
cyanide to from a thin skin is subsequently
quenched
30% NACN , 40% NA2CO3 , 30% NACL

13. Case depth is about 0.25mm
Negligible change in dimension
Distorition may occur

14. Screws
Nuts and bolts
Small gears

15. Here carbon and nitrogen are added on
the work piece surface by passing a gas
containing carbon and nitrogen

16.  Work piece kept in a furnace and heated to a
tempreature 800 to 900 c
 Natural gas containing ammonia and hydro
carbon is passed inside the furnace
 Carbon and nitrogen released from this gas at
high temp . and it react with iron on the work
piece surface and from iron carbide case
 Kept inside the furnace for 20 min
 0.5 mm case hardness obtained

17. Small gear
Bearings
Valve seats air craft
Guide way

18. Wear and corrosion resistance increased
Good fatigue resistance
Complicated shape components also
hardened

19. More time consuming process
Costly process
Not suitable for plain carbon steels

20. THANK YOU