Heat Treated Plain Bearing Materials Study

Friction and Wear Studies of Heat Treated
Plain Bearing Materials
Submitted By
SOUMIK SARKER
11006199
Under the Guidance of
Dr. Uday Krishna Ravella, Dr. Anil Midathada

TABLE OF CONTENTS
Introduction
Characteristics of Bearing materials
Advantages and limitations
Literature Review
Experiment Methodology
Sample Synthesis
Microstructure
Hardness
Friction and wear analysis
Conclusion
References

INTRODUCTION
Abstract: Our aim is to study the effect of heat treatment on compounds manufactured via
powder metallurgical route. Microstructural studies were carried on CuSn, CuSnC and CuSnTi
alloys under different mechanical loading parameters. The primary goal of this study is to
identify the alloy for plain bearing material by tribological study of the surface after heat
treatment. Hardness, weight loss and Co-efficient of friction and wear of the alloys were
studied using Pin On Disk Tribometer.

CHARACTERISTICS OF BEARING MATERIALS
High loading capacity: allowable compressive strength
Compatibility: prevent localize welding and seizure in the moving components
Corrosion resistance: should not oxidize
Conformability: should not deform
Embeddability: ability to embed any dirt or foreign particles to prevent if from abrasion.
Low coefficient of friction: sliding may cause wear
Low thermal expansion: metals expands or contracts due to change in temperature.
High thermal conductivity: it should be able to dissipate heat quickly
Wettability: affinity for lubricants
Elasticity: to permit bearing to the working conditions of the temporary external stresses.
Availability: cheap and readily available.

ADVANTAGES AND LIMITATIONS
Advantages
Low friction coefficient
Availability
Compactness
Desired characteristics
Limitations
Wear and abrasion due to moving and sliding parts
In presence of high friction more power is needed
If desired characteristics are not fulfilled it might get damaged
Limited life of inadequately made bearing materials

Literature ReviewAUTHORS
REVIEW REFERENCES
T.
Rameshkumar,
I. Rajendran,
and A. D.
Latha
They investigated the mechanical properties and the tribology of plain bearing alloy. The Sliding friction and wear properties of Al-Sn alloy against high carbon
high Cr steel were studied at different loading conditions by oil lubrication at the sliding speed of 1m/s. The oil was preheated. Friction and wear were studied by
pin-on-disk tribometer. The weight loss was measured and wear and friction characteristics were calculated w.r.t. time, depth of wear, speed and load. Wear was
studied using SEM. Thus, it was concluded that the hardness increased by 1.225 times more than the pure Al, Friction coefficient to decrease as well as the main
wear mechanism of the alloy was due to plastic deformation and abrasion.
1
M. BABIĆ, R.
NINKOVIĆ, S.
MITROVIĆ, I.
BOBIĆ
The effects of heat treatment on the material properties and the tribology of the ZA-27 alloys during conditions of dry sliding. The samples were treated up to
370o
C and were water quenched. Thus their experiments resulted in changes in the microstructure and decreasing strength and hardness properties, but showed
increase in elongation. The rate of change if increase was due to increasing solutionizing time. Their tests on tribology resulted that heat treatment of the ZA
alloy castings has a very significant influence on the improvement of their properties.
2
Erol
FEYZULLAH
OĞLU et al
Tested the tribology of Al based bearing alloys with different chemical compositions, by forging and heat treating the materials and these experiments were tested
in oil lubricated conditions. They heat treated (T6) on the materials and examined the different wear test results. Although forging didn’t have any effect on mass
loss but increased the hardness of these materials. They concluded that the Al-Pb alloy had superior wear resistance to Al-Si alloy under oil lubrication. 3
Sanjay Kumar,
Dr. S. S. Sen
the wear behavior of different convectional materials under stipulated conditions that is speed, load, lubrication and time. They also investigated the relationship
between coefficient of friction, friction forces, speed and load. Suggestions were made for the best suitable material for the journal bearing applications from the
tested materials. Results showed that value of wear rates were very low in case of MoS2 in comparison to other materials under similar working conditions. It was
concluded that it had the best properties and was also cheaper.
4
A. Gőkçe, F.
Findik
studying the comparison of the powders mixed. Lubricating and compacting of the specimens using hand operated Carver hydraulic press. Sintering,
delubrication and dewaxing were performed. They found that the green and theoretical density increased with the increment of compacting pressure. 5
Andrea
Manente and
Giulio Timelli
the unfailing increased use of light alloys in the automotive industry, due to the need for decreasing the vehicle’s self-weight. Therefore, they took an approach
for optimizing the wheel cast alloy production by applying on A356-T6 18-inch wheels. These wheels were produced with an AlSiMg alloy. Processes such as
heat treating, powder coating, solutionizing, water quenching were implemented on the casting. As-cast, quenched, powder coated and heat treated wheel were
analyzed respectively. They concluded that these treatments were best suited and great impact on productivity and manufacturing costs of wheels.
6

AUTHORS
REVIEW REFERENCES
Rashmi
Mittal,
Aruna
Tomar,
Devendra
Singh
spray forming technique to produce a net shaped disc of Al-Si-Pb alloys. They investigated the microstructures in different regions of the preforms. The results
showed equiaxed grains of primary Al and Si was present within these grain boundary. The grain size of the elements we also noted thoroughly which was
dispersed throughout the aluminum phase matrix. 7
Anton
Panda, Jozef
Jurko and
Iveta
Pandová
the heat treatment of bearing rings may lead to risks of deformations caused by internal tension. To eliminate this internal tension, hardening is followed by
tempering. Thus, lowering the internal tensions with effect on reduced deformations and ring ovality. 8
Praveen
Kumar
Nigam and
Prabhash
Jain
They investigated under two circumstances, i.e. two heat treatment types like solutionizing and ageing were used to the nickel, aluminum and bronze alloy
containing Fe, Al, and Ni as the elements for alloying. They heat treated this alloy to get their effect on the mechanical properties of the alloy. For example the
tensile, compression strength and strain. The process of solutionizing temperature was done at 850o
C and 900o
C at regular intervals of 30 mins for about four times.
These samples were water quenched in order to bring them to a allowable temperature. The mechanical examinations were carried out in order to determine its
properties at different conditions. The heat treating was processed in optimized conditions. They concluded that the tensile stress of the alloy increased with strain.
This rate of increase in the stress was initially very high but later the rate lowered. During compression, the higher stresses were recorded with respect to the
increasing strain just before the specimen fracture. Therefore, the solution that came up at the end was that the mechanical properties of the specimen was affected
by the heat treatment processes.
9
Anna
Krzymień,
Piotr
Krzymień
the properties of different material matrixes and compared these materials. They studied the properties of bearing materials and their requirements that are needed
for their operation as well as the tendency of their future development. They tested the fatigue strength the distribution of Si particle. Discussions related to the
problems of properties were pointed out. Effect of Sn and Si in the alloy. By this they concluded the best possible material for the bearing alloys used for the slide
bearing of crank mechanism.
10

MATERIALS PROPERTY
SELECTION AND DESIGN
 Selection and design of the bearing material using Copper alloys. It is a trimetal alloy where different elements are alloyed by powdered
metallurgy to the Copper matrix. These have usual applications like Low and medium loaded bearings, good seizure resistance, lead
free.
 Cu is most commonly used for alloying because these have sufficient solid solubility. These should avoid stressing and corrosion in the
material. These elements also have significant effects on the work hardening in many ways.
 Sn and Graphite is used to increase the hardness factor of the alloy and it also increases the wear resistance.
 For heat treatment of these alloys, the strain hardening may supplement the strength developed. Hence, the elements increase the
strength and decrease the ductility.
 The Ti content helps to decrease the brittleness of the materials. Though it’s melting point is very high hence it melts partially to bind
the other alloying elements.
Density: 9.3 grams % % %
Cu (Copper) Balance Balance Balance
Sn (Tin) 8 8 8
C (Carbon) 0.8 3 1
Ti (Titanium) 0 0 5
Zn St (Zinc Sterate) 1 1 1
Table for composition

MATERIAL SYNTHESIS
After the successful designation of the material, we will now synthesize
the alloy as per the required process. We chose the powdered metallurgy
as the most convenient method for synthesizing the required materials.
We develop three different kind of alloys which are as CuSn, CuSnC
and CuSnTi. Each alloy has its own mass ratio and have undergone
different heat treatment temperature according to their properties.
INFLUENCE OF HEAT TREATMENT

To synthesize the materials, we firstly weigh each of the elements in the powdered
form.
After we have calculated the weight of the powdered element of the required grade.
We mix the different powder to make three different mixtures of alloy in the mixer
blender that is used to blend the powder. This takes about 30 minutes for each alloy.
The three alloys are then put into dyes to make the green part of the required bearing
materials.
As soon as we develop the green part of the correct quality, i.e. of the required
density and dimension we then arrange these green parts into different trays and put
it in the oven for heat treatment, in which the samples are sintered at the temperature
of 810ºC. The density was maintained as 7grams/cc and weight as 9grams.
(N.B. 1% of Zinc sterate was also used so that it could help in as a good binding agent
which does not affect the property of the material as it drains out during heat
treatment due to it’s ow melting point.)

STUDY OF THE MATERIAL PROPERTIES
Firstly, The microstructural properties of the alloy were seen with the help of metallurgical
microscopy and study the test subject for its segregation of the different alloying elements in
its matrix.
Secondly, Physical properties like hardness test were conducted. The surface roughness of
the friction discs were also noted for the study of wear properties.
Lastly, Dry friction test, using a Pin on disk tribometer, to study the friction and wear
resistance properties of the material that was synthesized.
The results were noted for each material and were compared.

MICROSTRUCTURAL PROPERTIES
Microstructure of CuSn alloy

Microstructure of CuSnTi alloy

HARDNESS PROPERTIES
150 KGF
unit: HRB
CuSnC CuSn CuSnTi
Straight orientation 90 107 77
Tilt orientation 86 102 125
Table for hardness

FRICTION AND WEAR PROPERTIES
 It is to be noted that each sample weighs about 9.3 grams. Hence, the weight measured during friction test consist the
weight of the fixture as well as the sample.
 Each cycle of test was done with a span of 15 minutes cycle and 5 readings of weight loss were noted after washing the
debris by ethanol.
 The track diameter was taken as 40mm. The surface roughness of the disk on which the experiment was conducted was
also noted.
 The load was taken as 5N and the speed was calculated as 477 RPM.
 Distance covered per cycle was 1800 m.
TRACK SPEED CALCULATION
V= 1m/s
D (Track diameter) = 40mm
We get N as 477 rpm

1 2 3 4 5
CuSnTi
(Default wt:
62.3585)
62.3572
Wt loss: 0.0013
Final wt: 9.3-
0.0013= 9.299
62.3565
Wt loss: 0.002
Final wt: 9.3-
0.002=9.298
62.35630
Wt loss: 0.0022
Final wt: 9.3-
0.0022=9.2978
62.35595
Wt loss: 0.00255
Final wt: 9.3-
0.00255=9.29745
62.35530
Wt loss: 0.0032
Final wt: 9.3-
0.0032=9.2968
CuSnC
(Default wt:
58.47592)
58.47578
Wt loss: 0.00014
Final wt: 9.3-
0.00014=9.29986
58.47530
Wt loss: 0.00062
Final wt: 9.3-
0.00062=9.29938
58.47507
Wt loss: 0.00085
Final wt: 9.3-
0.00085=9.29915
58.47467
Wt loss: 0.00125
Final wt: 9.3-
0.00125=9.29875
58.47337
Wt loss: 0.00255
Final wt: 9.3-
0.00255=9.29745
CuSn
(Default wt:
59.41500)
59.40800
Wt loss: 0.007
Final wt: 9.3-
0.007=9.293
59.39344
Wt loss: 0.02156
Final wt: 9.3-
0.02156=9.27844
59.37732
Wt loss: 0.03768
Final wt: 9.3-
0.03768=9.26232
59.32790
Wt loss: 0.0871
Final wt: 9.3-
0.0871=9.2129
59.16930
Wt loss: 0.2457
Final wt: 9.3-
0.2457=9.0543
WEIGHT LOSS PER CYCLE
The weight is measured in grams (fixture + sample weight) after each cycle of run by washing and drying the
debris using ethanol solution. Sample weight is 9.3 grams.
Table for Weight Loss

Weight Loss vs number of readings

SURFACE ROUGHNESS PROPERTIES (ERROR)
Roughness in the Disks used. The disks are made of High carbon High chromium Steel
Measuring speed : 0.6 m/s
Evaluation Length : 5mm
Cut Off : 0.8mm
Disk 1 (unit
in µm)
Ra Rasd Ramax Ramin
Reading 1 0.086 0.023 0.123 0.056
Reading 2 0.080 0.018 0.104 0.056
Reading 3 0.068 0.013 0.094 0.055
Disk 2 (unit
in µm)
Ra Rasd Ramax Ramin
Reading 1 0.173 0.094 0.341 0.085
Reading 2 0.099 0.069 0.238 0.039
Reading 3 0.143 0.117 0.401 0.057
Table for Roughness of Discs

Average of all 5 readings for CuSnTi
Fx (Frictional Force, Kg)
Mean= 0.28186
SD= 0.34868
Fz (Load, Kg)
Mean= 0.70692
SD= 0.99636
COF (Coefficient of Friction)
Mean= 0.7608
SD= 0.117476
Average of all 5 readings for CuSnC
Mean= 0.243
SD= 0.2063
Fz (Load, Kg)
Mean= 0.59874
SD= 0.63276
Mean= 0.51832
SD= 0.046696
Average of all 4 readings for CuSn
Mean= 1.51405
SD= 0.81675
Fz (Load, Kg)
Mean= 4.8645
SD= 1.366225
Mean= 0.8427
SD= 0.0872875

CONCLUSION
 Thus, we can conclude with the results that by comparing the microstructure we see that the titanium has not completely
melted. This is due to it’s high melting point. Where as, the other two samples CuSn and CuSnC have sintered properly.
 It is found that the CuSn has a coarse grain microstructure where as the CuSnC has Carbon traces in the grain
microstructure.
 Temperature of 810ºC was not adequate to sinter the CuSnTi alloy, but if the temperature was to be increased the Tin and
Copper would have drained out due to it’s low melting point against Titanium.
 Hardness of CuSnC and CuSn was more than the CuSnTi.
 The wear properties varied vastly and was seen that the CuSn wore out drastically and there are a huge difference in the
weight loss by the sample. On the other hand, CuSnC and CuSnTi have shown positive results. Thus, there are less loss
due to friction. CuSnC came out to be the better sample to tolerate the friction test with minimum loss of weight.
 The friction Force in case of CuSnC was minimum and was maximum incase of CuSn.
 The CuSn experienced the maximum load where as the CuSnC took in less in compared to CuSnTi.
 The coefficient of friction was most in case of CuSn and least incase of CuSnC
 Thus we can conclude that CuSnC is a better bearing material than the other 2 samples.

REFERENCES
1) Tribometer, P., Rameshkumar, T., & Latha, a D. (2010). Investigation on the Mechanical and Tribological Properties of Aluminium- Tin Based Plain Bearing Material, 32(2), 3-10.
2) Babic, M., Ninkovi, R., Mitrovi, S., Bobi, I., Engineering, M., & Sciences, N. (2007). Influence of Heat Treatment on Tribological Behavior of Zn-Al Alloys. Tribology in Industry,
29(1), 23–31.
3) Feyzullahoğlu, E., Ertürk, A. T., & Güven, E. A. (2013). Influence of forging and heat treatment on wear properties of Al–Si and Al–Pb bearing alloys in oil lubricated conditions.
Transactions of Nonferrous Metals Society of China, 23(12), 3575–3583. http://doi.org/http://dx.doi.org/10.1016/S1003-6326(13)62903-9
4) Kumar, S., & Sen, D. S. S. (2014). Selection of the Material on the Basis of Wear and Friction in Journal Bearing. International Journal of Innovative Research in Science, Engineering
and Technology, 03(09), 16003–16013. http://doi.org/10.15680/IJIRSET.2014.0309032
5) Gokce, a., & Fındık, F. (2008). Mechanical and physical properties of sintered aluminum powders. Journal of Achievement in Materials and Manufacturing Engineering, 30(2), 157–
164.
6) Manente, A., & Timelli, G. (2011). Optimizing the Heat Treatment Process of Cast Aluminium Alloys. Recent Trends in Processing and Degradation of Aluminium Alloys, 9, 197–
220. Retrieved from http://www.researchgate.net/publication/221920070_Optimizing_the_Heat_Treatment_Process_of_Cast_Aluminium_Alloys/file/50463523203bc88427.pdf
7) Mittal, R. (2012). Thickness uniformity and microstructure of disc shape spray formed Al-Si-Pb alloys. Advanced Materials Letters, 3(1), 55–63.
http://doi.org/10.5185/amlett.2011.5261
8) Panda, A., Jurko, J., & Pandová, I. (2012). Deformation Reduction of Bearing Rings by Modification of Heat Treating.
9) Nigam, P. K., & Jain, P. (2013). Effect of heat treatment on tensile and compression strength of nickel aluminium bronze (Cu-10% Al-5% Ni-5% Fe). Archives of Applied Science
Research, 5(1), 224–230. Retrieved from http://scholarsresearchlibrary.com/aasr-vol5-iss1/AASR-2013-5-1-224-230.pdf
10) A. Krzymien, P. Krzymien Properties of the bearing alloys used for slide bearing of crank mechanism. Journal of KONES Internal Combustion Engines 2004, vol. 11, No. 1-2

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