The document summarizes an investigation into the mechanical properties of AISI 420 martensitic stainless steel after undergoing a quenching and partitioning (Q&P) heat treatment process. The study examined the microstructure, hardness, tensile strength, and fracture behavior of samples treated with different Q&P temperatures and times. Key findings include a significant increase in hardness and tensile strength compared to annealed samples, evidence of retained austenite contributing to ductility, and development of a temperature regulator for the salt bath Q&P process.

2. GROUP NO 13
MUHAMMAD BILAL MY-10003
FAHAD IQBAL MY-10010
SHAHJAHAN HASSAN MY-10025
HASEEB KIANI MY-10047
SUPERVISOR: Mr. MUHAMMAD SAMIUDDIN
CO-SUPERVISOR: Mr. KASHIF IQBAL
To Investigate the Mechanical Properties of AISI 420
Martensitic Stainless Steel after Quenching &
Partitioning Process.

3. RECOMMENDATION

4. 1. INTRODUCTION
1
1.1 OVERVIEW OF THE PROJECT
Quenching and partitioning process is a future generation heat
treatment process which is used to attain a optimum ductility and
hardness in steels.
The mechanical properties were determined by tensile test and the
Rockwell hardness test.
Nature of fracture were determined by Fractography technique.
The metallurgical microscope was used to study the
microstructures after performing Metallography techniques on
different samples.

5.  Q&P opens the way to develop steel microstructures based
on the exceptionally advantageous combination of
austenitic(Retained) and martensitic phases at the industrial
scale.
 Q&P will provide significant progress in the automotive sector,
which demands lower fuel consumption and increased safety.
1.2 DEVELOPMENT OF QUENCHING AND PARTITIONING
PROCESS
2

6. 1.3 Q AND P PROCESS
 The Q&P process consists of the following sequential steps:
3
QUENCHING STEP
• Quench to a temperature below the Ms but
above the Mf to form a mixture of martensite
and austenite.
PARTITIONING STEP
• Subsequent isothermal treatment at the same
temperature (one-step treatment) or at a higher
temperature (two step treatment), in order to
transfer the C from the supersaturated
martensite into the austenite.

7. 1.4 HT CYCLE FOR Q & P PROCESS
4

8. 1.5 PHASES AT DIFFERENT STAGES OF Q AND P PROCESS
5

9. 1.6 PROPERTIES OF Q & P STEELS
6
High Ductility
High Strength
Improved
Weldability
Good
Formability
Improved Strain
Hardenability

10. 1.7 COMPARISION BETWEEN Q&P AND Q&T PROCESS
Difference between tempering and partitioning is
No fine carbide precipitation during partitioning,leading to the
stabilization of retained austenite due to the diffusion of carbon atoms
from martensite.
Silicon controls carbide precipitation.
F is ferrite, TM is tempered
martensite, and RA/UM is
retained austenite or untempered
martensite
Showing a block of tempered
martensite containing carbide
precipitation. 7

11. Comparison of impact toughness at room temperature between Q&P and
Q&T at various partitioning (or tempering) temperatures.
1.8 COMPARISON OF IMPACT TOUGHNESS BETWEEN Q&P
AND Q&T STEELS
8

12. Comparison of the engineering stress-strain curves and strain
hardening of Q&P and Q&T
1.9 COMPARISON OF STRESS-STRAIN CURVES OF Q&P
AND Q&T STEELS
9

13. 2. LITERATURE REVIEW
10
YEAR OF
PUBLICATION
PURPOSE METHOD EQUIPMENTS RESULTS
2005
The
“Quenching
and
Partitioning”
Process:
Background
and Recent
Progress
The process
concept is
reviewed, along
with the
thermodynamic
basis for the
partitioning
treatment, and a
model for
designing some
of the relevant
processing
temperatures.
These concepts
are applied to
silicon-containing
steels.
X-ray
diffraction and
TEM
• Q&P creates
microstructures
containing carbon-
enriched retained
austenite.
• Attractive property
combinations have
been achieved.

14. 11
YEAR OF
PUBLICATION
PURPOSE METHOD EQUIPMENTS RESULTS
2010
Analysis of 42
Si-Cr steel after
quenching and
partitioning.
The effect of
heat treatment
conditions on
the
microstructure
and properties
of low-alloyed
42SiCr steel
Laser Scanning
Confocal
Microscope
(LSCM)
• The UTS achieved
were around 2000
MPa with YS
varying from 1400
MPa to 1780 MPa.
• The ductility of
Processed steel
was 20% for all
processing
strategies.

15. 14
YEAR OF
PUBLICATION
PURPOSE METHOD EQUIPMENTS RESULTS
2011
To study the
Quenching and
partitioning
treatment of a
low-carbon
martensitic
stainless steel
Fraction of
retained
austenite,
Mechanical
properties,
Study micro
structure,
Ms Temperature
SEM,TEM
XRD .
HARDNESS
TESTER.
TENSILE
TESTER
• Q&P treatment
retains a
significant fraction
of austenite in low
carbon martensitic
stainless steel.
• A sufficient
amount of carbon
enriches into
untransformed
austenite at an
appropriate
partitioning
temperature.
• Improved strength
and ductility

16. 13
YEAR OF
PUBLICATION
PURPOSE METHOD EQUIPMENTS RESULTS/FINDINGS
2012
Quenching and
Partitioning
(Q&P)
Processing of
Martensitic
Stainless Steels
The hardness of
Q&P specimens
obtained at
different
quench
temperatures.
XRD is used for
analysis of
structural
changes in
materials, tensile
properties, and
phase fraction.
Dilatometry,
tensile test,
hardness test,
XRD.
• Martensitic
stainless steels are
suitable for the
Q&P process.
• The presence of
fresh martensite
led to brittle
fracture and
increased
hardness.
• The presence of
retained austenite
increases ductiltiy
and shows ductile
fracture.

17. 3.1 SELECTED MATERIAL
3 EXPERIMENTAL WORK
16
COMPOSITION OF AISI 420
C Si Mn P S Cr Fe
0.22 1.0 1.0 0.020 0.005 14 BALANCE
AISI 420

18. 18
3.1.1 CHARACTERISTICS OF AISI 420
 High Hardness
 Magnetic
 Good corrosion
 Ductility

19. 3.1.2 APPLICATIONS OF AISI 420
17
Dental and Surgical implants
Pump Shafts
Plastic Molds and Dies
Gauges
Needle Valves
Cams
Ball Bearings, etc.

20. 3.1.3 GENERAL HEAT TREATMENT PROCESSES
FOR AISI 420
 Annealing - Full anneal - 840-900°C, slow furnace cool to 600°C
and then air cool.
 Process Anneal - 735-785°C and air cool.
 Hardening - Heat to 980-1035°C, followed by quenching in oil or
air. Oil quenching is necessary for heavy sections.
 Temper at 150-370°C to obtain a wide variety of hardness values
and mechanical properties.
18

21. 19
Annealing 01
Q and P process 06
Spare samples 06
3.2 SAMPLE PREPARATION FOR TENSILE TESTING
 Sample prepared from private workshop and threaded from
Materials Engineering Department.
STANDARD FOLLOWED FOR TENSILE TESTING
ASTM E8: “Standard Test Methods For Tension Testing Of Metallic Materials”
QUANTITY OF SAMPLES
Total No. of samples 01+06+06 = 13

22. 20
3.3 AISI 420 steel - T.T.T. diagram
(Transformation – Time– Temperature)

23. 21
3.4 ANNEALING
• Heat to 860°C, followed by slow furnace cool.
Heat Treatment Cycle For Annealing

24. 22
Salt Composition NaNO3 + KNO3
Percentage Of Each Salt 55% NaNO3 and 45% KNO3
Weight Of Each Salt 2.2Kg NaNO3 and 1.8Kg KNO3
Melting Of Salt Salt melted in steel container
Melting Temperature Of The Salt 200°C
Furnace Used For Melting The Salt oven
3.5 SALT BATH PREPARATION

25. 23
3.6 QUENCHING AND PARTITIONING PROCESS
•The schemes followed for Q and P process are as follows
SAMPLE #1
Heating Temperature: 1000°C
Partitioning Temperature: 200°C
Partitioning Time: 5 minutes
SAMPLE #2
Heating Temperature: 1000°C
Partitioning Temperature: 220°C
Partitioning Time: 10 minutes

26. 24
SAMPLE #3
Heating Temperature: 1020°C
Partitioning Temperature: 230°C
Partitioning Time: 20 minutes
SAMPLE #4
Heating Temperature: 1020°C
Partitioning Temperature: 240°C
Partitioning Time: 30 minutes

27. 25
SAMPLE #5
Heating Temperature: 1020°C
Partitioning Temperature: 200°C
Partitioning Time: 40 minutes
SAMPLE #6
Heating Temperature: 1020°C
Partitioning Temperature: 220°C
Partitioning Time: 50 minutes

28. 26
3.7 TENSILE TESTING
 Tensile Test
 Test performed in metallurgical department.
Machine Used
 Universal tensile testing machine.
3.8 HARDNESS TESTING
Hardness test
 Test performed in metallurgical engineering department.
Machine Used
 Rockwell hardness tester.

29. 29
3.9 FRACTOGRAPHY
Test were performed in microscopy lab.
3.10 METALLOGRAPHY
Metallography was performed in metallography lab.
Steps for metallography
1. Mounting
2. Grinding
3. Polishing
4. Etching
5. Microscopic studies

30. 30
4 RESULTS AND DISCUSSIONS
This portion includes the acquired results and their effects on AISI
420 steel after Q and P.
4.1 HARDNESS TESTING RESULTS OF Q AND P STEEL
•Hardness test were performed in mechanical testing lab on HRC
scale.
•Next slide shows the hardness result chart for the Q and P
steels.

31. 30
4.1 HARDNESS TESTING RESULT CHART
SPECIFICATIONS HARDNESS AVERAGE HARDNESS
As Received
14 HRC
16.1HRC
17HRC
17.5HRC
Sample-1
49HRC
47.3HRC
46 HRC
47 HRC
Sample-2
36.5 HRC
43.1HRC
46 HRC
47 HRC
SAMPLE-3
38 HRC
41.3HRC
43 HRC
43 HRC
SAMPLE-4
48.5 HRC
51HRC
53.5 HRC
51 HRC
SAMPLE-5
40.5 HRC
46.5 HRC 44.3HRC
46 HRC
SAMPLE-6
42.5 HRC
46HRC
47 HRC
48.5 HRC

32. 27
SAMPLE PARTIONING
TEMPERATURE
(°C)
PARTIONING
TIME
(MINUTES)
HARDNESS
(HRC)
ANNEALED 860 - 16.1
1 200 05 47.3
2 220 10 43.1
3 230 20 41.3
4 240 30 51.0
5 200 40 44.3
6 220 50 46.0
4.1.1 EFFECT OF TIME AND TEMPERATURE ON
HARDNESS OF Q AND P AISI 420

33. 33
4.2 FRACTOGRAPHY OF Q AND P SAMPLES
Fractured Surface of Annealed
Sample At Magnification 20X
Fractured Surface of Annealed
Sample At Magnification 10X
4.2.1 FRACTURED SURFACE OF ANNEALED AISI 420
TENSILE SPECIMEN

34. 34
Fractured Surface Of Q and P AISI
420 STEEL At Magnification 10X
Fractured Surface Of Q and P AISI
420 STEEL At Magnification 15X
4.2.2 FRACTURED SURFACE OF Q AND P AISI 420 TENSILE
SPECIMEN (BEST OBSERVED)

35. 29
4.3 MICROSTRUCTURES OF Q & P SAMPLES
(BEST OBSERVED)
AISI 420 Etched with Aqua regia for 15
seconds at {200X}, showing martensite
and small fraction of retained austenite
after Q and P at 200°C for 40 minutes.
AISI 420 Etched with Aqua regia for 15
seconds at {200X}, showing martensite
and small fraction of retained austenite
after Q and P at 220°C for 50 minutes.

36. 36
AISI 420 Etched with Aqua regia for 15
seconds at {200X}, showing martensite and
small fraction of retained austenite after Q
and P at 230°C for 20 minutes.
AISI 420 Etched with Aqua regia for 15
seconds at {200X}, showing martensite and
small fraction of retained austenite after Q
and P at 240°C for 30 minutes.
4.3 MICROSTRUCTURES OF Q & P SAMPLES
(BEST OBSERVED)

37. 28
SAMPLE PARTIONING
TEMPERATU
RE
(°C)
PARTIONING
TIME
(MINUTES)
TENSILE
STRENGTH
(Kgf/cm2)
ANNEALED 860 - 6211
1 200 05 15348
2 220 10 15116
3 230 20 15930
4 240 30 15465
5 200 40 15465
6 220 50 14767
TENSILE
STRENGTH
(MPa)
609
1505
1482
1562
1516
1516
1448
4.4 EFFECT OF TIME AND TEMPERATURE ON
TENSILE STRENGTH OF Q AND P AISI 420

38. 31
4.4.1 TENSILE PROPERTIES
Obtained stress/ strain curve of Q
AND P AISI 420 steel (BEST
OBSERVED)
Obtained stress/ strain curve of
ANNEALED AISI 420 steel

39. 32
 HARDNESS
A remarkable increase in hardness was observed by an amount of 35
HRC.
 FRACTOGRAPHY
Inherent ductility was again observed, by the indication of shear lips.
 MICROSTRUCTURE
Presence of Retained Austenite in small fraction indicates the ductile
behaviour after Q and P process.
 TENSILE STRENGTH
Tensile strength of AISI 420 increased from 609MPa to 1562MPa was
observed.
4.5 DISCUSSIONS

40. 40
5 DEVELOPMENT
During quenching and partitioning process, temperature
maintenance at partitioning temperature in normal salt bath tank was
not possible to achieve.
It was observed that during partitioning stage, temperature rises from
the target temperature due to heat dissipation and heat conduction.
Therefore, it was decided to develop a “TEMPERATURE REGULATOR
SALT TANK” to achieve the required temperature maintenance.

41. 41
TEMPERATURE REGULATOR SALT TANK

42. 42
COMPONENTS OF SALT BATH TEMPEATURE REGULATOR
Stainless steel Tank Fire Clay
Temperature resistant sheets

43. 43
Electric Motor
Controller
Electric Motor
Thermocouple

44. 44
Rotating Blades
ContractorHeating Elements

45. 45
WORKING PRINCIPLE
•HEATING ELEMENTS PROVIDE REQUIRED TEMPERATURE TO
REGULATE TEMPERATURE LEVEL WITH RESPECT TO TIME AND
TEMPERATURE.
•ELETRIC MOTOR IS USED TO REGULATE THE LIQUID SALT FLUID
WHICH PERFORMS FOLLOWING OPERATIONS.
1. HOMOGENIZE TEMPERATURE IN SALT TANK.
2. AVOID SAMPLE STIKNESS WITH SALT AND BATH.
3. ALLOW UNIFORM HEAT DESIPATION.

46. 46
OTHER APPLICATIONS OF TEMPERATURE
REGULATOR BATH
 CARBURIZING
 NITRIDING
 MELTING OF ALUMINIUM AND OTHER METALS AT
BELOW 1000 DEGREE CENTIGRADE.
 HEAT TREATMENT OF FERROUS ALLOYS

47. 47
video

48. 6. CONCLUSION
 At low quench temperatures, the microstructure of Q&P
processed specimens consisted of tempered (primary)
martensite and retained austenite.
 At high quench temperatures, fresh (secondary)
martensite as well as retained austenite was present.
 The presence of fresh martensite led to brittle fracture.
Fresh martensite also resulted in increased hardness.
 The mechanical stability of retained austenite increased
with carbon concentration of austenite being highest at the
lowest quench temperature.
36

49. 38
7. RECOMMENDATIONS
 The phase fraction of the individual phases after Q and P
treatment can be determined by XRD technique.
 The detail microstructures can be observed by SEM analysis
technique.
 The industrial applicability of the Q&P process will be improved
in terms of compositions, treatments and properties to develop
a controlled and reproducible production process for these
materials, and be prepared for future developments.
 Q&P will provide significant progress in the automotive sector,
which demands lower fuel consumption and increased safety.

50. 8. REFERENCES
40
J.G. Speer, D.K. Matlock, B.C. De Cooman and J.G. Schroth, Acta Mater., 51
(2003) 2611-2622.
J.G. Speer, A.M. Streicher, D.K. Matlock, F.C. Rizzo and G. Krauss, Austenite
Formation and Decomposition, ed. E.B. Damm and M. Merwin, TMS/ISS,
Warrendale, PA, USA, 2003, pp. 505-522.
John G. Speer, David V. Edmonds, Fernando C. Rizzo, David K. Matlock,
Current Opinion in Solid-State and Materials Science, 8 (2004) 219-237
 Sarikaya M, Thomas G, Steeds JW, Barnard SJ, Smith GDW. Solute element
partitioning and austenite stabilization in steels. In: Proceedings of an
International Conference on Solid to Solid Phase Transformations, ed. H.I
Aaronson, Warrendale, PA: TMS; 1982. p. 1421-1425.
Streicher AM, Speer JG, Matlock DK, De Cooman BC. Quenching and
partitioning response of a Si-added TRIP sheet steel. In: Speer JG
Editor. Proceedings of the International Conference on Advanced High-Strength
Sheet Steels for Automotive Applications, Warrendale, PA: AIST; 2004. p. 51-62.

51. 41
We would like to THANKS of our Department Chairman.
DR.UMAIR ALAM.
Our Project Supervisor MR.MUHAMMAD SAMIUDDIN .
Our Project Co-supervisor MR.KASHIF IQBAL for his peerless guidance.
MR ALI MUHAMMAD SIDDIQUI.
MR RIZWAN.
MR AQEEL AHMED SHAH.
MR IFTIKHAR AHMED CHANNA.
MR NAFIS UL HAQUE.
We would also THANKS to all the
 LAB ATTENDANTS
 MR MUHTASHIM for his guidance and efforts and
All faculty members of the Metallurgical department who helped us a lot
in completing the experimental procedure.

52. 52