MACHINING WITH CRYOGENCALLY TREATED TOOL INSERTS

1. A Seminar on
“MACHINING WITH CRYOGENCALLY TREATED TOOL
INSERTS”
By
V. JAGADEESHWARA ACHARI
16125A0341
Under the Guidance of:
VIDYASAGAR REDDY Mtech
Associate Professor
DEPARTMENT OF MECHANIACAL ENGINEERING
SREE VIDYANIKETHAN ENGINEERING COLLEGE
(AUTONOMOUS)
A.RANGAMPETA, TIRUPATI - 517 102
INDIA
2018 - 2019

2. CRYOGENIC TREATMENT
Processing of materials at -196oC

3. INTRODUCTION
 Cryogenic word originates from the Greek words
'kryos' meaning "frost" and 'genic' meaning "to
produce.“
 Cryogenic in branches of engineering that involve the
study of very low temperatures, how to produce
them, and how materials behave at those
temperatures.
 Cryogenic deals with low temperatures, from 100°K
to absolute zero.

4. Literature suevey
Barron reported improvement in wear characteristics of steels
after CT
Sing observed improvement in tool life by 9% to 22% in deep
cryogenic treatment of various materials.
Stewart observed reduction in normal tool force by 25% as well
as parallel force by 20% after cryogenic treatment of tungsten
carbide tools
A. Y. L. Yong evaluated the performance of cryogenically treated
tungsten carbide tool in turning of carbon steels

5. CRYOGENIC TREATMENT
Shallow
Cryogenic
Treatment (193K-
113K)
Deep Cryogenic
Treatment (113K-
77K)
Classification of
Cryogenic
treatment
Cold Treatment
(213K-193K)

6. Steps in Cryogenic Treatment Cycle
..

7. Basic Mechanism
Sintered Tungsten Carbide tools were developed to
meet the modern machining requirements.
Tungsten carbide tool materials generally have a
cobalt binder.
Cobalt has the property to deform during wear
condition
Cobalt extrudes from the surface due to plastic
deformation during wear
Cobalt gets pulled out from the surface with the
bounded hard α phase resulting in the formation of
grooves on surface

8. Cont
The results show that there is reduction in cobalt from
64% to 11% from β phase after CT of tungsten carbide tool
as a result of diffusion process.
 The formation of η phase involves the dissolution of the
original carbides into the cobalt binder as a result of
diffusion process.
Change in the cobalt content in cobalt matrix and
formation of η carbide causes refinement of structure which
has contribution in the improvement of wear resistance of
WC-Co sample.

9. Microstructure Analysis
α phase-
β phase-
ή phase-
β phase-
α - phaseή - phase

10. Hardness & Size of Particles
Sample Average (HV1) Change in Size of
Crystallite(mm)
As received 1591.00 0.03205
Cryotreated
Cryotreated& tempered at 250 0
C, air
cooled
Cryotreated& tempered at 250 0
C, furnace
cooled
Cryotreated& tempered at 300 0
C, air
cooled
Cryotreated & tempered at 300 0
C, furnace
cooled
1695.67
1651.67
1671.76
1783.46
1859.43
0.06665
0.02360
0.09690
0.09870
0.09951

11. Factors affecting on Cryogenic Treatment
20%60%
10% 10%
Cooling rate and
heating rate
Soaking period
Cryogenic
tremperature
Tempering /
Atificial aging

12. Conclusion
•Most useful when performed instantly after quenching and succeeded
by progressive tempering.
•Optimization needed for both its performance and cost
•Improvement in the wear characteristics is also observed due to
refinement of the structure
•Treated samples show better and stabilized values of hardness.
•Tempering as post treatment process has a significant influence on the
phases present in tungsten carbide