This document discusses various surface hardening processes including nitriding, carburizing, cyaniding, and carbonitriding. It provides details on the nitriding process such as using medium carbon steel and alloy steel, heating to 450-550°C in the presence of ammonia gas for 20-80 hours to introduce nitrogen into the surface. Nitriding increases properties like wear resistance, endurance limit, and corrosion resistance without dimensional changes. Applications include gear and engine parts. The document also summarizes the carburizing and cyaniding processes which involve adding carbon or carbon and nitrogen to the surface through use of carbon-rich materials or molten cyanide compounds.

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