Flexural strength also known as the bending strength which plays a vital role in the industries where the heavy load application is implemented. The study reports show that shotpeening technique considerably improves the mechanical properties of a material such as hardness, fatigue strength, corrosion resistance, flexural (or) bending strength etc. Here the shot material used for shotpeening is glass beads and the target material is aluminum alloy of grade AA-2024 T3 which is widely used in the automobile and aircraft industries due to its light weight and strength. The experimental results show there is an improvement in the flexural strength of AA2024-T3material after shotpeening

1. http://www.iaeme.com/IJMET/index.asp 384 editor@iaeme.com
International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 02, February 2019, pp. 384–390, Article ID: IJMET_10_02_040
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=02
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication Scopus Indexed
INVESTIGATION OF SURFACE PROPERTY OF
AA2024 T3 WHEN SHOT PEENED USING GLASS
BEADS
A. Rajesh
Assistant Professor, Sri Krishna College of Engineering & Technology, Coimbatore-641008,
G. Vignesh Subramaniam
PG Scholar, Sri Krishna College of Engineering & Technology, Coimbatore-641008,
G.Shanthosh and T.Shoban
UG Students, Sri Krishna College of Engineering & Technology, Coimbatore-641008.
ABSTRACT
Flexural strength also known as the bending strength which plays a vital role in the
industries where the heavy load application is implemented. The study reports show that
shotpeening technique considerably improves the mechanical properties of a material
such as hardness, fatigue strength, corrosion resistance, flexural (or) bending strength
etc. Here the shot material used for shotpeening is glass beads and the target material is
aluminum alloy of grade AA-2024 T3 which is widely used in the automobile and
aircraft industries due to its light weight and strength. The experimental results show
there is an improvement in the flexural strength of AA2024-T3material after
shotpeening.
Keywords: Shot Peening, Flexural Strength, Glass Beads, AA2024-T3
Cite this Article: A. Rajesh, G. Vignesh Subramaniam, G.Shanthosh and T.Shoban,
Investigation of Surface Property of Aa2024 T3 When Shot Peened Using Glass Beads,
International Journal of Mechanical Engineering and Technology, 10(2), 2019, pp. 384–
390
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=02
1. INTRODUCTION
Shotpeening is a surface strengthening mechanical process in which high pressured or forced
shot ball materials generally made of metals or ceramics is allowed to hit on the target material
surface to create a permanent plastic deformation and residual stress at the surface of the
material for the improvement of surface mechanical strength and corrosion resistance. If a
material is subjected to a continuous or cyclic load for a long period of time, the initiation of
crack starts to occur and the material slowly begins to break and completely tends to deform,

2. A. Rajesh, G. Vignesh Subramaniam, G.Shanthosh and T.Shoban
http://www.iaeme.com/IJMET/index.asp 385 editor@iaeme.com
this mechanism is known as fatigue failure. The fatigue strength differs for different materials
depending on its properties.A research paper reveals that the propagation of crack caused by
fatigue for AL 7475-T7351 is reduced after PSP [1]. Subsequent diffusion of hydrogen into the
metal cause material to brittleness & fracture. Shot peening (SP) resists Hydrogen
embrittlement in a metal [2]. Fatigue life for mild carbon steel of grade AISI 1045 and 1050is
improved after SP and the peening process parameters is controlled by using artificial neural
network[3]. Hardness is the measurement of resistance offered by the material due to
mechanical indentation or abrasion is known as hardness. Metals, ceramics, concrete &super
hard materials shows more hardness while comparing to the material like plastics, woods etc.
Hardness greatly depends on ductility, elastic stiffness, plasticity, strain, strength, toughness,
viscoelasticity, and viscosity. The micro hardness for SAF 2507 duplex stainless steel is
increased after SP[4]. Porosity also known as void fraction is a measure of the empty spaces in
a material. Porosity plays a major role in the fields of pharmaceutics, ceramics, metallurgy,
materials, manufacturing, earth sciences, soil mechanics and engineering. Selective laser
melting is an additive manufacturing process. The porosity distribution for the selective laser
melted rotation bending test samples made up of Alsi10Mg is reduced after SP. Improvement of
fatigue life is also observed after SP [5,6]. Surface roughness also known as surface finish or
surface texture or surface topography (ST) or surface nature orSimply roughness of a
component. In tribology in design, rough surfaces will have more wear and high coefficient of
friction than the smooth surfaces. Roughness helps to determine how a real object interacts with
its environment. SP increases the depth of the residual stress & surface roughness for steel
made up of high manganese alloy [7].
Surface Integrity (SI) is the surface condition of a component after subjecting it to the
various manufacturing process. SI plays a major role in the SP process. A comparison study for
fatigue strength of Titanium alloy which was allowed to the different machining process was
done and also for after SP is carried out for the same. The titanium alloy of grade Ti-6Al-4V is
subjected to the various machining process such as end milling, surface grinding, electron beam
melting etc…and the fatigue strength of the same is compared and analyzed. Also the fatigue
properties of Ti-6Al-4V after SP is considerably improved [8]. Grain Refinement [GR] also
known as the refinement of grains or reduction in the grain size in a metal or alloy which affects
the hardness and quality of a material.GR is a strengthening mechanism for improving
mechanical properties without any loss in ductility. It depends on chemical composition,
deformation and microstructure of a material. SP improves GR of NAB alloy [9]. Thermal
growth [TG] also known as thermal expansion is the ability of a material to change in
dimensions with respect to change in temperature. When a substance is subjected to heating, the
molecules kinetic energy is increased. Or simply TG is the enhancement of heat & temperature
when a material is induced to heating. SP also plays a vital role in fire safety expenditures and it
is observed that SP greatly resists TG of a component [10]. Corrosion Pits [CP] is also known
as pitting corrosion or pitting is a severe localized corrosion which leads to the formation of
little holes in a material. Though CP of depth300μm doesn’t affect the fatigue life of steam
turbine blade made up of steel after the SP process or simply fatigue life is maintained or
improved after SP even after the formation of CP [11].
Friction is the resistance offered by any material surface when it is subjected to colliding or
rubbing it with on to the other material surface. High friction leads to wearing of a material
which causes a material loss or simply material removal. The cyclic up and down or back and
forth linear motion is known as reciprocating motion or reciprocation. There is an friction
reduction of 33% was found due to reciprocal sliding after simultaneous SP or continuous SP of
hard and soft particles of an mechanical component[12].Probabilistic Analysis(PA)is one of the
computational method used in analysis of algorithms to estimate the complexity of computation
in an algorithm. It uses an assumption of maximum all set of inputs that possible in a

3. Investigation of Surface Property of Aa2024 T3 When Shot Peened Using Glass Beads
http://www.iaeme.com/IJMET/index.asp 386 editor@iaeme.com
probabilistic distribution. There is a significant improvement of fatigue life of aluminum alloy
of grade 7050-T7451 by using PA was reported. SP by using ceramic Z425 shots shows a
greater improvement of fatigue life for AA 7050-T7451 [13].An analytical approach was
carried out to determine the depth of residual stress of a material after SP before subjecting it to
the various hardening treatments and also there is an improvement of fatigue life was noted
[14].Surface characters for stainless steel of grade 316L manufactured by selective laser melting
is enhanced after PSP process [15].
Thus the above literature survey reveals that shot peening enhances the various mechanical
properties of a material. In this paper the test results show the bending resistance for AA2024-
T3 alloy is improved after the effect of shotpeening. The flexural strength for the material
before shotpeening and after shotpeening was carried out and results were plotted.
2. EXPERIMENT DETAILS
1. Specimen preparation: The specimen is prepared as per the ASTM standards for the
flexural strength test. The material chosen is Aluminum alloy of grade AA-2024 T3 due to its
light weight and strength used in many industrial applications. A rectangular shape of
dimension 150mm×30mm×3mm is made for the testing.
The chemical composition for AA-2024 T3 is given in table 1.
Table 1 Chemical composition of AA 2024 T3 (% Wt.)
Content (wt. %)
Specimen Si Fe Cu Mn Mg Cr Zn Ti Al
AA2024-T3 0.05 0.5 3.8-4.9 0.3-0.9 1.2-1.8 0.1 0.25 0.15 Bal
2. Shot peening: Pneumatic shot peening technique is used in which the pressurized air
source is used mixed with the glass bead shot balls made to hit on the target material. Shot
peening machine was used for the process as shown in fig 2. AA-2024 T3 before and after shot
peening was shown in fig 3a&3b.The shot peening process parameters and details were
mentioned in table 2.
Figure 2 Shot peening Machine

4. A. Rajesh, G. Vignesh Subramaniam, G.Shanthosh and T.Shoban
http://www.iaeme.com/IJMET/index.asp 387 editor@iaeme.com
Figure 3a AA-2024 T3 before Shot peening Figure 3b AA-2024 T3 after Shot peening
Table 2 Shot Peening process parameters
Peening Pressure 0.07 Mpa
Peening distance between target material and nozzle gun 60 mm
Peening intensity 5 mm/A
Shot material Glass Beads
Target material AA 2024-T3
Shot size diameter 0.7mm to 0.9mm
Nozzle dia for peening gun 9mm
3. Flexural strength testing: The bending strength test for AA-2024 T3 before and after
shotpeening was carried out by using flexural strength testing machine. The material after
subjecting to the bending test before and after shotpeening was shown in the fig 4a&4b. The
test results were plotted and the material before shotpeening & after shotpeening was studied
and compared.
3. RESULTS AND DISCUSSIONS
1. The graph results shown in fig 5a is the maximum bending strength for the material AA-2024
T3 before the shotpeening process. The maximum stress that the material can with stand before
shot peening is 785 MPa. For this point at 785MPa the material can resist its maximum strength
and after that point (i.e.) above 785MPa the component slowly tends to bend or deform and
causing permanent plastic deformation of a material.

5. Investigation of Surface Property of Aa2024 T3 When Shot Peened Using Glass Beads
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Figure 5a Bending strength of AA 2024-T3 before shot peening
2. The graph results shown in fig 5b is the maximum bending strength for the material AA-
2024 T3 after the shotpeening process. The maximum stress that the material can with stand
after shotpeening is 798 MPa.Comparing the test results from 1 & 2, there is an increase in
resistance by 13 MPa of the bending strength for AA-2024 T3 after the effect of shot-peening
process.
Figure 5b Bending strength of AA 2024-T3 after shot peening
4. CONCLUSION
The flexural strength test before and after shot peening was conducted, the test results were
studied and compared. From the results, the paper reveals that when AA-2024 T3 is shot peened
by using glass beads there is a considerable improvement in the bending resistance for AA-
2024 T3 material was noted. An improvement of 3-5% and an increase of 13Mpa of stress for
the bending resistance were reported. The various surface asperities of a component such as
surface strength, fatigue strength, surface hardness, and toughness will also improve along with
the bending strength. The shot peened AA-2024 T3 can be used in the various industrial,
automobile and aircraft industries due to its light weight and strength.
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6. A. Rajesh, G. Vignesh Subramaniam, G.Shanthosh and T.Shoban
http://www.iaeme.com/IJMET/index.asp 389 editor@iaeme.com
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