International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 4, Issue 5, May 2015
ISSN 2319 - 4847
Analytical and Experimental Investigation
of Contribution of Burnished Parameters on
Roughness and Micro Hardness of AA6351
1
Arvind Ghodake, Prof. Bhamre V.G.2 , Prof. Londhe B.C.3
1
Department of Mechanical Engg. SND COE & RC YEOLA
2
Department of Mechanical Engg. SND COE & RC YEOLA
3
Department of Mechanical Engg. SND COE & RC YEOLA
ABSTRACT
Burnishing is a surface enhancement process in which plastic deformation of surface induces compressive residual stresses. It
is a cold working chip less process in which material is pressed against burnishing force or pressure. By imparting compressive
stresses in the surface layer, the tensile range on the component surface was reduced. From the literature it is viewed that
several methods are available for inducing compressive residual stresses on component surface layer to improve mechanical
properties of metal and alloys. Ball burnishing is one of the method for surface enhancement and with the effective burnishing
parameter the surface finish and micro hardness of the metals or alloys gets improved.
The test will carried out for AA6351 alloy material, 0.10 % Cu, 0.4-1.0% Mn , 0.6 % Fe , 0.4-1.2 % Mg, 0.6-1.3 % Si and
reminder is Al. The material having mechanical properties as T.S. =150-160Mpa.This AA6351 alloy is widely used in aerospace
industry as well as marine industry. In this work attention is given toward a design such a tool which is suitable for burnishing
operation of conventional lathe machine. The ball burnishing tool is manufactured with hard steel ball. The experimental work
has been carried out considering suitable burnishing parameters as feed (mm/rev), speed (rpm), depth of penetration (mm) and
number of tool passes. Keeping rest parameters constant. The kerosene is used as coolant.
In this work ball burnishing process will carried out on specimens as per experimental matrix with burnishing input
parameters as feed, speed, depth and number of tool passes on conventional lathe machine. After experimentation the results
will be obtained for surface roughness and micro hardness for each specimen. From the experimental results as per
experimental matrix the ANOVA and regression analysis will carried out to find out contribution of burnishing parameter for
surface roughness and improvement in micro hardness properties of AA6351 alloy. Then the microscopic examination will be
done to analysis the effect on microstructure of AA6351. The maximum contribution of burnishing parameter will be
investigated for further burnishing operation which will give best mechanical properties for alloys.
Keywords: Burnishing, Design of Experiments, Micro hardness, Surface Roughness.
I. INTRODUCTION
In the present scenario of manufacturing good surface finish and dimensional accuracy plays an important role. A good
surface finish is essential in many applications, e.g. in the moulds and dies, bioengineering, semiconductor and optical
industries. In the injection molding process, the surfaces finish required is Ra= 0.1μm or less. Surface finish is
important not only as an indication of expert workmanship, but it has effects on the life and function of the component.
Finishing processes such as grinding, polishing, lapping and honing are commonly employed to improve surface finish.
Burnishing is a cold working process in which plastic deformation occurs by applying a pressure through a ball or
roller on metallic surfaces. It is a finishing and strengthening process. Improvements in surface finish, surface
hardness, wear resistance, fatigue resistance, yield and tensile strength and corrosion resistance can be achieved by the
application of this process. It also improves exterior quality of surface.
1.1 Importance of the Problem
The main importance of this work is getting required surface quality and improvement in the properties of materials.
1.2 Scope of the work
The surface and subsurface nature of materials is usually characterized by an tensile residual stresses which is most
prominent effect on the fatigue life of the component, burnishing is the process which can provide deep, stable , surface
compression process for improved surface integrity characteristics and fatigue life of the component. The mechanical
properties of surface of material can be improved by this operation.
The present work focuses on surface roughness and Micro hardness of AA6351 aluminum alloy using full factorial
design and it analyzed using ANOVA Method. After analysis the effect various burnishing parameters of ball
burnishing which effect the surface roughness and Micro hardness of AA6351 Aluminum alloy , the percentage
contribution of parameters is being evaluated. The ball burnishing process can be applied for any material with desired
Volume 4, Issue 5, May 2015
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 4, Issue 5, May 2015
ISSN 2319 - 4847
burnishing parameters which can satisfactorily gives surface quality and service life. This work can be helpful for
deciding input process parameters for carry out surface enhancement and improvement in surface properties of any
material under specified operating conditions. It can give significant process cycle time advantage, lowering the capital
investment cost.
II. BALL BURNISHING TOOL DESIGN
For designing of ball burnishing tool different parts are designed and finally all parts are assembled for making model
of ball burnishing tool. The assembled model for ball burnishing tool is as shown in figure 1.
Figure 1: Assembly model of ball burnishing tool
2.1 Work Material
The experimental work is carried out to investigate the effect of process parameter of ball burnishing on surface
roughness, hardness and fatigue life of AA6351 alloy work material. This is most widely used alloy in wide variety of
general applications in small scale industry as well as large industries. The main focus of selection of this material is
the alternative for steel which has maximum chances of corrosion and having high density. The aluminum alloy is
widely used in aerospace and space shuttle with high quality and good service life.
The composition and mechanical properties of work material are given in Table 1 and Table 2 respectively.
Table 1: Composition of work material
Element
Cu
Mg
Mn
Si
Fe
Al
0.10
0.4-1.2
0.4-1.0
0.6-1.3
0.6
Reminder
Weight ,%
Density,
g/cc
2.6-2.8
Table 2: Mechanical properties of work material
Tensile
Yield
Modulus
Hardness,
Strength,
Strength,
Elasticity
HB
Mpa
Mpa
GPa
250
150
95
70-80
of
,
Poisson’s
ratio
0.033
Figure 2 shows the work piece material .
Figure 2: Work piece
Figure 3 shows Experiment setup on PL lathe machine.
Volume 4, Issue 5, May 2015
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Volume 4, Issue 5, May 2015
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Figure3: Experiment setup on PL lathe machine
2.2 Process parameter selection
The input parameters and their levels are shown in Table 3 Depth, speed, feed rate and number of passes is taken as a
burnishing input parameters. For each factor two levels are chosen one is low level and another is high level.
Table 3: Burnishing input parameters and levels
Factors / Levels
Code
Low(-)
High(+)
Feed Rate (mm/Rev)
A
0.04
0.051
Speed (rpm)
B
850
950
Depth of Penetration(mm)
C
0.50
0.75
No. of tool passes
D
1
2
III. PERFORMING THE EXPERIMENT
Form the full factorial design for 24 factorial the total numbers of experiments performed are 16. 24 factorial
= 2× 2 × 2 × 2 = 16 total experiments
Based on this design the actual parameters are tabulated as shown in Table 4
Table 4: 16 runs for experiment
Actual Values
Coded values
RUN
A
B
C
D
A
B
C
D
1
0.04
850
0.50
1
-1
-1
-1
-1
2
0.04
850
0.50
2
-1
-1
-1
1
3
0.051
850
0.50
1
-1
-1
1
-1
4
0.051
850
0.50
2
-1
-1
1
1
5
0.04
950
0.50
1
-1
1
-1
-1
6
0.04
950
0.50
2
-1
1
-1
1
7
0.051
950
0.50
1
-1
1
1
-1
8
0.051
950
0.50
2
-1
1
1
1
9
0.04
850
0.75
1
1
-1
-1
-1
10
0.04
850
0.75
2
1
-1
-1
1
11
0.051
850
0.75
1
1
-1
1
-1
12
0.051
850
0.75
2
1
-1
1
1
13
0.04
950
0.75
1
1
1
-1
-1
14
0.04
950
0.75
2
1
1
-1
1
15
0.051
950
0.75
1
1
1
1
-1
Volume 4, Issue 5, May 2015
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
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Volume 4, Issue 5, May 2015
16
0.051
950
0.75
2
1
1
1
ISSN 2319 - 4847
1
3.1 ANOVA (Analysis of Variance)
The purpose of the experimentation should be to reduce and control variation of process; subsequently decisions must
be made concerning which parameters affect the performance of a product or process. ANOVA is the statistical method
used to interpret experimental data and make the necessary decisions. The method was developed by Sir Ronald Fisher
in the 1930's as a way to interpret the results from agricultural experiments. ANOVA has a lot of mathematical beauty
associated with it. ANOVA is a statistically based decision tool for detecting any differences in average performance of
groups of item tested. [3]
3.1.1 Statement of the problem
The objective of the present work is to investigate the effect of factors that is (A) feed rare (mm/rev), (B) speed (rpm)
and (C) depth (mm) and (D) for the burnishing on AA6351 alloy.
3.1.2 Response variable
In these investigations “surface roughness and micro hardness” are typically chosen as response variables. The entire
experimentation performed on PL lathe machine.
3.1.2.1 Response table for surface roughness
A response Table 6 is now created which contains the sum of Ra values for each factor and each level. From Table 5, it
is clear that feed rate is taken as factor A and at level L1 and L2 its value in mm/rev taken during experimentation
trials. Now the sum for factor A at level L1, this is obtained by adding all values of Ra that have feed rate 0.04 mm/rev.
Table 5: Response of surface roughness
Actual Values
Surface
RUN
Roughness(Ra)(µm)
A
B
C
D
1
0.04
850
0.50
1
0.156
2
0.04
850
0.50
2
0.116
3
0.051
850
0.50
1
0.094
4
0.051
850
0.50
2
0.131
5
0.04
950
0.50
1
0.192
6
0.04
950
0.50
2
0.156
7
0.051
950
0.50
1
0.088
8
0.051
950
0.50
2
0.149
9
0.04
850
0.75
1
0.117
10
0.04
850
0.75
2
0.102
11
0.051
850
0.75
1
0.108
12
0.051
850
0.75
2
0.089
13
0.04
950
0.75
1
0.105
14
0.04
950
0.75
2
0.069
15
0.051
950
0.75
1
0.120
16
0.051
950
0.75
2
0.113
Table 5.6 shows that the sum of Ra values for factor A (feed rate) at level L1 and L2; factor B (speed) at level L1 and
L2 ,factor C (depth) at level L1 and L2 and factor D (Number of passes) at level L1 and L2.
Table 6: Level total for each factor
Factor
A (feed rate)
B(speed)
C (depth)
D (passes)
1.013
0.913
1.082
0.980
L1
0.892
0.992
0.823
0.925
L2
1.905
1.905
1.905
1.905
Total
0.121
0.079
0.259
0.055
Difference
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Table 7 shows the average factor level for surface roughness.
Table 7: Average factor level
Factors
A (feed rate)
B(speed)
C (depth)
0.1266
0.1141
0.1352
L1
0.1115
0.1240
0.1828
L2
ISSN 2319 - 4847
D (passes)
0.1225
0.1156
3.1.3ANOVA Table for Surface Roughness
The table 8 shows ANOVA Table for surface Roughness. The calculations are done based on following equations
wherein the reading for factor A at each level are used to show the calculations.
Sum of Squares (SSA) = 2 × [(MA1 – M) 2 + (MA2 – M) 2
(1)
Total sum of SS
= SSA + SSB + SSC + SSD
(2)
Factors
A (feed rate)
B(speed)
C (depth)
D (passes)
Total
Table 8: ANOVA Table for surface roughness
SS
DF
MS
2.280 × 10- 4
3
7.6 × 10- 5
9.802 × 10- 5
3
3.26 × 10- 5
-3
8.665× 10
3
2.895 × 10- 3
-5
4.762× 10
3
1.578 × 10- 5
-3
9.039 × 10
12
3.01938× 10- 3
F
4.8162
2.0659
183.46
1
-
%P
2.522
1.084
95.862
0.526
-
3.1.4 Response table for micro hardness
A response Table 10 is now created which contains the sum of Hv values for each factor and each level. From Table 9,
it is clear that feed rate is taken as factor A and at level L1 and L2 its value in mm/rev taken during experimentation
trials. Now the sum for factor A at level L1, this is obtained by adding all values of Hv that have feed rate 0.04 mm/rev.
Table 9: Response for micro hardness
Actual Values
RUN
Micro Hardness (Hv)
A
B
C
D
1
0.04
850
0.50
1
143.3
2
0.04
850
0.50
2
143.2
3
0.051
850
0.50
1
145.8
4
0.051
850
0.50
2
140.7
5
0.04
950
0.50
1
142.3
6
0.04
950
0.50
2
146.6
7
0.051
950
0.50
1
144.8
8
0.051
950
0.50
2
145.9
9
0.04
850
0.75
1
147.6
10
0.04
850
0.75
2
143.9
11
0.051
850
0.75
1
142.4
12
0.051
850
0.75
2
150.1
13
0.04
950
0.75
1
145.7
14
0.04
950
0.75
2
146.6
15
0.051
950
0.75
1
142.3
16
0.051
950
0.75
2
145.5
Table 10 shows that the sum of Ra values for factor A (feed rate) at level L1 and L2; factor B (speed) at level L1 and L2
,factor C (depth) at level L1 and L2 and factor D (Number of passes) at level L1 and L2.
Table 10: Level total for each factor
Factor
A (feed rate)
B(speed)
C (depth)
D (passes)
1159.2
1157
1151.6
1154.2
L1
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Volume 4, Issue 5, May 2015
1157.5
1159.7
1164.1
L2
2316.7
2316.7
2316.7
Total
1.7
2.7
12.5
Difference
Table 10 shows the average factor level for surface roughness.
Table 10: Average factor level
Factors
A (feed rate)
B(speed)
C (depth)
144.90
144.625
143.95
L1
144.68
144.962
145.51
L2
ISSN 2319 - 4847
1162.5
2316.7
8.3
D (passes)
144.275
145.312
ANOVA Table for Micro Hardness
The table 12 shows ANOVA Table for Micro hardness. The calculations are done based on following equations
wherein the reading for factor A at each level are used to show the calculations.
Sum of Squares (SSA) = 2 × [(MA1 – M) 2 + (MA2 – M) 2]
(3)
Total sum of SS
= SSA + SSB + SSC + SSD
(4)
Factors
A (feed rate)
B(speed)
C (depth)
D (passes)
Total
SS
0.0481
0.1135
2.2510
1.0764
3.489
Table 12: ANOVA Table for micro hardness
DF
MS
3
0.01603
3
0.03780
3
0.75030
3
0.35880
12
1.1629
F
1
2.35
46.80
22.38
-
%P
1.3786
3.253
64.517
30.8512
-
IV. CONCLUSION
Ball burnishing operation is successfully carried out on AA6351 alloy material which implies surface enhancement of
the material. The mechanical properties of the selected material gets improved. The following conclusion is made for
the successful results.
1. Full factorial design is successful in Surface Roughness and Micro hardness of the AA6351 alloy. In the experiment
the independent variables are feed rate, speed, depth of penetration and number of burnishing tool passes while the
dependent variables (output variables) are surface roughness (Ra) and Micro hardness respectively. Roughness and
hardness experiment on AA6351 alloy is successful by varying burnishing parameters (feed rate, speed, depth and
number of passes ) and output variables are Ra and Hv. Based on the extensive experimental investigations, statistical
analysis using ANOVA and the regression method the following observations were made:
a. Performing ball burnishing operation on AA6351 with burnishing parameters is successful.
b. The below table 13 shows percentage contribution of burnishing parameters on Roughness and micro hardness.
Table 13: Contribution of Burnishing Parameters on Ra & Hv
Response
% Contribution of
Feed
Surface
% Contribution of
Speed
% Contribution of % Contribution of No.
Depth
of Passes
2.522
1.084
95.8623
0.5238
1.3786
3.253
64.517
30.8512
Roughness
Micro hardness
2. After successful experimentation it is concluded that the microstructure of material is dose not changes with these
burnishing parameters.
3. The tool designed for ball burnishing process is worked with better efficiency and provides better output response
for surface properties.
4. Ball burnishing process reduces surface roughness maximum from 0.4516µm to 0.069µm with higher speed of 950
rpm and 0.75 mm depth of penetration of AA6351 alloy.
5. Ball burnishing process improves micro hardness maximum from 144.9Hv to 150.1Hv with speed of 850 rpm,
0.75 mm depth of penetration and 0.051 mm/rev feed for AA6351 alloy.
6. The kerosene is used as lubricant which dissipate heat during ball burnishing process and provides damage of hard
steel ball rotate freely by lubricating action
Volume 4, Issue 5, May 2015
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International Journal of Application or Innovation in Engineering & Management (IJAIEM)
Web Site: www.ijaiem.org Email: editor@ijaiem.org
Volume 4, Issue 5, May 2015
ISSN 2319 - 4847
REFERENCES
[1]. A.S. Maheshwari, U.M. Shirsat, “Optimization of Two ball burnishing process parameters to improve material
properties”, S.V. National Institute of Technology, (2011), Surat – 395 007, Gujarat, India, PP-531-535,
[2]. U.M. Shirsat, B.B. Ahuja, “Parametric Analysis of combined turning and ball burnishing process”, International
journal of engineering and material science, (2004), Vol. 11, PP-391-396.
[3]. A.P. Ghodake , A.S. Maheshwari, “Effect of Burnishing Process on Behavior of Engineering Materials”,
International Journal of Scientific Research”, e- ISSN:2278-1684, Vol-5, Issue-5, Mar-Apr-2013, PP:09-20.
[4]. R.K. Jain, “Engineering Metrology”, Terminology of surface Texture & surface roughness, Khanna Publication,
20th Edition, (2010), PP- 639-646 & 654-655.
[5]. V.B. Bhandari, “Design of machine elements, Design of tool parts, Mc Hill publication, Second Edition, (2009),
PP-391-398
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