Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel
The influence of friction time on the hardness, tensile properties, and microstructure of the welded samples is investigated. With increasing friction time, the hardness and tensile strength values increase too. The hardness of the welding interfaces is higher than that of the base alloys. Microstru...
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Інститут металофізики ім. Г.В. Курдюмова НАН України
2013
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Ates, H. Kaya, N. 2016-07-01T09:19:46Z 2016-07-01T09:19:46Z 2013 Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel / H. Ates, N. Kaya // Металлофизика и новейшие технологии. — 2013. — Т. 35, № 2. — С. 241-252. — Бібліогр.: 17 назв. — англ. 1024-1809 PACS numbers:06.60.Vz, 62.20.fq,62.20.Qp,81.20.Vj,81.40.Lm,81.40.Pq, 82.80.-d https://nasplib.isofts.kiev.ua/handle/123456789/104080 The influence of friction time on the hardness, tensile properties, and microstructure of the welded samples is investigated. With increasing friction time, the hardness and tensile strength values increase too. The hardness of the welding interfaces is higher than that of the base alloys. Microstructures of the welds are examined by the optical and scanning electron microscopy. The results show that all welding joints are perfectly bonded and free of any cracks, pores, and defects. The tensile fracture of welded joint occurred in the AISI 304 side. The chemical composition of the interfaces and deformation zones are detected using energy dispersive spectroscopy. Diffusion of the Cr and Ni is evident on the AISI 1060 side. Досліджено вплив тривалости тертя на твердість, властивості при розтягу та на мікроструктуру зварних зразків. При збільшенні тривалости тертя твердість та границя міцности на розрив також збільшуються. Міцність поверхні зварних контактів виявляється більшою, аніж у основних стопів. Мікроструктуру зварних швів було досліджено методами оптичної й електронної мікроскопії. Показано, що зварні з’єднання були досконало звареними та не мали ніяких тріщин, пор і дефектів. Руйнування при розтягу відбувалося з боку криці AISI 304. Хемічний склад зварних контактів і зон деформації досліджено за допомогою енергодисперсійної спектроскопії. Спостерігалася дифузія Cr та Ni в бік криці AISI 1060. Исследуется влияние времени трения на твёрдость, свойства при растяжении и на микроструктуру сварных образцов. При увеличении времени трения твёрдость и предел прочности на разрыв также увеличиваются. Прочность поверхности сварных контактов оказывается выше, чем у основных сплавов. Микроструктура сварных швов исследуется методами оптической и электронной микроскопии. Показано, что все сварные соединения были идеально сварены и не имели никаких трещин, пор и дефектов. Разрушение при растяжении происходит со стороны стали AISI 304. Химический состав сварных контактов и зон деформации исследуются с помощью энергодисперсионной спектроскопии. Наблюдается диффузия Cr и Ni в сторону стали AISI 1060. The authors wish to thank Prof. Dr. A. Kurt, Prof. Dr. N. Kahraman and Prof. Dr. I. Uygur for their invaluable contribution. Also special thanks to Turkish Track Factory for their support and guidance during the experimental stage. en Інститут металофізики ім. Г.В. Курдюмова НАН України Металлофизика и новейшие технологии Физика прочности и пластичности Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel Влияние времени трения на микроструктуру и механические свойства сваренных трением нержавеющей стали AISI 304 на стали AISI 1060 Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
| title |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel |
| spellingShingle |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel Ates, H. Kaya, N. Физика прочности и пластичности |
| title_short |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel |
| title_full |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel |
| title_fullStr |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel |
| title_full_unstemmed |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel |
| title_sort |
effect of friction time on microstructure and mechanical properties of friction welded aisi 304 stainless steel to aisi 1060 steel |
| author |
Ates, H. Kaya, N. |
| author_facet |
Ates, H. Kaya, N. |
| topic |
Физика прочности и пластичности |
| topic_facet |
Физика прочности и пластичности |
| publishDate |
2013 |
| language |
English |
| container_title |
Металлофизика и новейшие технологии |
| publisher |
Інститут металофізики ім. Г.В. Курдюмова НАН України |
| format |
Article |
| title_alt |
Влияние времени трения на микроструктуру и механические свойства сваренных трением нержавеющей стали AISI 304 на стали AISI 1060 |
| description |
The influence of friction time on the hardness, tensile properties, and microstructure of the welded samples is investigated. With increasing friction time, the hardness and tensile strength values increase too. The hardness of the welding interfaces is higher than that of the base alloys. Microstructures of the welds are examined by the optical and scanning electron microscopy. The results show that all welding joints are perfectly bonded and free of any cracks, pores, and defects. The tensile fracture of welded joint occurred in the AISI 304 side. The chemical composition of the interfaces and deformation zones are detected using energy dispersive spectroscopy. Diffusion of the Cr and Ni is evident on the AISI 1060 side.
Досліджено вплив тривалости тертя на твердість, властивості при розтягу та на мікроструктуру зварних зразків. При збільшенні тривалости тертя твердість та границя міцности на розрив також збільшуються. Міцність поверхні зварних контактів виявляється більшою, аніж у основних стопів. Мікроструктуру зварних швів було досліджено методами оптичної й електронної мікроскопії. Показано, що зварні з’єднання були досконало звареними та не мали ніяких тріщин, пор і дефектів. Руйнування при розтягу відбувалося з боку криці AISI 304. Хемічний склад зварних контактів і зон деформації досліджено за допомогою енергодисперсійної спектроскопії. Спостерігалася дифузія Cr та Ni в бік криці AISI 1060. Исследуется влияние времени трения на твёрдость, свойства при растяжении и на микроструктуру сварных образцов. При увеличении времени трения твёрдость и предел прочности на разрыв также увеличиваются.
Прочность поверхности сварных контактов оказывается выше, чем у основных сплавов. Микроструктура сварных швов исследуется методами оптической и электронной микроскопии. Показано, что все сварные соединения были идеально сварены и не имели никаких трещин, пор и дефектов. Разрушение при растяжении происходит со стороны стали AISI 304. Химический состав сварных контактов и зон деформации исследуются с помощью энергодисперсионной спектроскопии. Наблюдается диффузия Cr и Ni в сторону стали AISI 1060.
|
| issn |
1024-1809 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/104080 |
| citation_txt |
Effect of Friction Time on Microstructure and Mechanical Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel / H. Ates, N. Kaya // Металлофизика и новейшие технологии. — 2013. — Т. 35, № 2. — С. 241-252. — Бібліогр.: 17 назв. — англ. |
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241
PACS numbers:06.60.Vz, 62.20.fq,62.20.Qp,81.20.Vj,81.40.Lm,81.40.Pq, 82.80.-d
Effect of Friction Time on Microstructure and Mechanical
Properties of Friction Welded AISI 304 Stainless Steel
to AISI 1060 Steel
Hakan Ates and Nihat Kaya*
Gazi University,
Faculty of Technology,
06500 Ankara, Turkey
*Gazi University,
Institute of Science and Technology,
06500 Ankara, Turkey
The influence of friction time on the hardness, tensile properties, and micro-
structure of the welded samples is investigated. With increasing friction
time, the hardness and tensile strength values increase too. The hardness of
the welding interfaces is higher than that of the base alloys. Microstructures
of the welds are examined by the optical and scanning electron microscopy.
The results show that all welding joints are perfectly bonded and free of any
cracks, pores, and defects. The tensile fracture of welded joint occurred in
the AISI 304 side. The chemical composition of the interfaces and defor-
mation zones are detected using energy dispersive spectroscopy. Diffusion of
the Cr and Ni is evident on the AISI 1060 side.
Досліджено вплив тривалости тертя на твердість, властивості при розтягу
та на мікроструктуру зварних зразків. При збільшенні тривалости тертя
твердість та границя міцности на розрив також збільшуються. Міцність
поверхні зварних контактів виявляється більшою, аніж у основних сто-
пів. Мікроструктуру зварних швів було досліджено методами оптичної й
електронної мікроскопії. Показано, що зварні з’єднання були досконало
звареними та не мали ніяких тріщин, пор і дефектів. Руйнування при ро-
зтягу відбувалося з боку криці AISI 304. Хемічний склад зварних контак-
тів і зон деформації досліджено за допомогою енергодисперсійної спект-
роскопії. Спостерігалася дифузія Cr та Ni в бік криці AISI 1060.
Исследуется влияние времени трения на твёрдость, свойства при растя-
жении и на микроструктуру сварных образцов. При увеличении времени
трения твёрдость и предел прочности на разрыв также увеличиваются.
Прочность поверхности сварных контактов оказывается выше, чем у ос-
новных сплавов. Микроструктура сварных швов исследуется методами
Металлофиз. новейшие технол. / Metallofiz. Noveishie Tekhnol.
2013, т. 35, № 2, сс. 241—252
Оттиски доступны непосредственно от издателя
Фотокопирование разрешено только
в соответствии с лицензией
© 2013 ИМФ (Институт металлофизики
им. Г. В. Курдюмова НАН Украины)
Напечатано в Украине.
242 Hakan ATES and Nihat KAYA
оптической и электронной микроскопии. Показано, что все сварные со-
единения были идеально сварены и не имели никаких трещин, пор и де-
фектов. Разрушение при растяжении происходит со стороны стали
AISI 304. Химический состав сварных контактов и зон деформации ис-
следуются с помощью энергодисперсионной спектроскопии. Наблюдается
диффузия Cr и Ni в сторону стали AISI 1060.
Key words: AISI 304 SS—AISI 1060, friction welding, microstructure, me-
chanical properties.
(Received December 29, 2011; in final version, February 12, 2013)
1. INTRODUCTION
Austenitic stainless steels based on relatively high amount of Cr and Ni
are excellent candidates to be used as structural materials in chemical
and food industry as well as in hospital surgical equipments. They ex-
hibit high ductility, excellent drawing and forming properties. The var-
ious fusion and solid state welding techniques can be used to join these
steels. Welding of machinery parts is necessary in the most of the engi-
neering applications. Just a few decades ago, materials were classified
as weldable and non-weldable, but innovations in technology enabled the
joining of majority of materials by fusion and solid state welding tech-
niques. Some of the fusion techniques are applied for various materials
[1—3]. The typical solid-state joining applications of diffusion welding
for various content of the aluminium metal matrix composites [4] and
FSW [5] have been studied in detail. Welding time, applied load, weld-
ing temperature and chemical composition of the steel are some of the
key parameters to control solid-state diffusion welding process.
Rotary friction welding is one of the solid state joining techniques,
which is applied to join similar and dissimilar counterparts. In this
technique, machinery components are brought into contact with one
another. While one of them remains stationary, the other is rotated
with the applied pressure. When the temperature of the interfaces has
reached an optimum value for the extensive plastic deformation, the
rotation is stopped, while the forging pressure remains unchanged or
increased. The application of an axial force maintains intimate contact
between the parts and leads to plastic deformation in the material near
the weld interface. If sufficient frictional heat has been produced dur-
ing softening, larger wear particles begin to expel from the interfaces,
and axial shortening of the components begins as a result of the ex-
pelled upsetting. In general, heat is conducted away from the interfac-
es, and plastic zone develops. The plasticized layer is formed on the in-
terfaces and the local stress system with the assistance of the rotary
movement extrudes material from the interface into the flash. It is
EFFECT OF FRICTION TIME ON MICROSTRUCTURE AND PROPERTIES OF STEEL 243
shown that the weld integrity is strongly affected by the rate of flash
expelled under the appropriate conditions [6]. Friction welding has a lot
of advantages over other welding processes. Among these advantages
are no melting, high reproducibility, short production time, low energy
input, limited heat affected zone (HAZ), avoidance of porosity for-
mation and grain growth and the use of non-shielding gases during
welding process. In addition, the technique is not only applied to round
specimens but is also used for rectangular components. It is called line-
ar friction welding and has recently been applied to the steel [7].
Although a large amount of previous studies [4—11] in similar and
dissimilar materials have been studied, mechanical properties of the
plain carbon steel to stainless steel joint by friction welding method
have never been reported up to date. Therefore, in this paper, the AISI
1060 and AISI 404 stainless steel are welded by friction welding and
the mechanical, microstructural properties and optimal welding condi-
tions of friction welded samples are examined.
2. MATERIALS AND METHODS
Chemical composition of plain carbon steel and stainless steel em-
ployed is presented in Table. Cylindrical test specimens of 20 mm in
diameter and 160 mm in the length were prepared for friction welding.
Before the friction welding, the surfaces facing each other were ma-
chined using a lathe. Before welding, the surfaces of the work pieces
were cleaned by a stainless steel brush and acetone to remove the oxide
layer and stains. Joining of these two dissimilar alloys was performed
on a continuous drive friction-welding machine of 300 kN capacity at a
constant rotation speed of 2000 rpm, and constant friction pressure
(P1) of 40 MPa and constant upsetting pressure (P2) of 60 MPa. Fric-
tion and upsetting pressures can be observed on the screen, and the
stages of welding sequence are controlled by solenoid valve. The fric-
tion time (t) was chosen as three, five, and seven seconds. Tensile test
specimens were prepared according to ASTM E8M-00b. Ultimate Ten-
sile Strength (UTS) and yield strength of the welded specimens were
determined. Hardness values (VH1) were determined using Shimadzu
TABLE. Chemical composition of tested materials.
Material C Cr Ni Si Mn P
AISI 1060 0.42 — — 0.21 0.45 0.02
Elements, wt.%
Material C Cr Ni Si Mn P
AISI 304 0.027 8.1 18.1 0.28 1.81 0.073
244 Hakan ATES and Nihat KAYA
HMV device. Measurements were taken in the welding centre through
base metal with a distance of 1 mm on either side of horizontal line.
Hardness values were measured in the welding centre through the di-
ameter with a distance of 2.5 mm on vertical line. For tensile strength
and hardness test values, at least, three specimens were prepared for
each parameter. The microstructure was investigated with the SEM
and optical microscopy. The AISI 1060 steel specimens were polished
and etched with a solution consisting of 4% Nital. AISI 304 SS etched
with a solution of 95% HCl and 5% OH—C6H2(NO2)3. The grains have
various shapes ranging from 10 μm to 300 μm in dimension. Typical
microstructures of materials can be seen in Fig. 1.
3. RESULTS AND DISCUSSIONS
3.1. Hardness Distribution
Figure 2, a shows the effect of friction time on the hardness distribu-
tion in the direction perpendicular to the weld interface of the as-
welded specimen. The maximum hardness values of joints were ob-
tained on the welding centre line. The hardness values generally in-
creased with friction time. Increasing hardness in the welding inter-
face can be related to the microstructure formed in the joint surface as
a result of the heat input and extensive plastic deformation. The hard-
ness of AISI 304 SS is 129 HV and the hardness value of the AISI 1060
steel is 254 HV, but measured hardness of welding interface is around
300 HV. We can suppose that microstructural evaluations around the
interface, diffusion of elements on the sides, work hardening, disloca-
tion density, grain refinement, and formation of precipitations may
cause this increase. Although the work hardening is effective on the SS
side, phase transformation, fine grains and formation of precipitates
Fig. 1. Microstructure of AISI 1060 (a) and AISI 304 (b).
EFFECT OF FRICTION TIME ON MICROSTRUCTURE AND PROPERTIES OF STEEL 245
and rapid cooling from the welding temperature resulted in the hard-
ening in the AISI 1060 steel. Similar hardness profile was also ob-
served for dissimilar materials couples [11]. One can suppose that the
hardness properties are influenced by an interactive effect of friction
time, which is combinations of heat input, range of plastic deformation
and degree of strain hardening. The influence of the friction time on
the vertical hardness distribution is also shown in Fig. 2, b. Both sides
of materials are hardened due to the austenite transformation to the
martensite formation, which is strongly affected by the cooling rate.
All hardness values are higher than those in the base metal are. It was
observed that hardness values increased from the centre through the
thickness of the specimen. The phase transformation and cooling rates
were the optimum around 5 mm away from the centre.
3.2. Tensile Properties
The influence of friction time on the tensile test result is shown in Fig. 3.
It can be seen that the yield strength slightly increased with the in-
Fig. 3. The effect of friction time on the tensile properties.
Fig. 2. The effect of friction time on horizontal (a) and vertical (b) hardness
distribution.
246 Hakan ATES and Nihat KAYA
crease of friction time. The UTS value for the AISI 1060 is 814 MPa
and for the AISI 304 SS it is 505 MPa [12]. The UTS strength corre-
sponds to about 130% of that for AISI 304 SS part and 81% of that for
AISI 1060 structural steel part. Although the UTS values were not in-
fluenced by friction time, the highest yield strength is obtained with
the highest friction time.
Fabricated joints were quite ductile in nature and 3 s and 5 s samples
failed in the AISI 1060 side due to the low elongation, which is only
17% compared to 70% for the SS. However, when the friction time in-
creased to the 7 s, failure occurred on the SS side (see Fig. 4) due to the
extended deformation and heat affected zone. Almost all specimens
failed on the base metals, showing that perfect joint interfaces were
obtained under the various friction times. It is reported that the choice
of welding parameters affects the microstructure [13—15]. If the fric-
tion time is held long, a broad diffusion zone with intermetallic phases
may be generated. Such parameters as short friction time, low friction
and low upsetting pressures will result in a weakly bonded joint.
Hence, the quality of the welds strongly depends on the temperature
attained by each substrate during welding process. Therefore, the flow
stress—temperature relationship for each metal will have an important
influence on the friction welding parameters. However, it is also re-
ported that a good strength can be obtained by a sufficient diffusion
and mechanical locking [11]. If optimum welding parameters are used
in friction welding, a perfect bonding can be achieved. In general, high
friction and upsetting pressures resulted in high toughness and hard-
ness in steel alloys [8]. It is also well known that for achieving high
strength at welding interface the brittle phases such as σ-phase, δ-
ferrite and oxide formations should be pushed away from the joint sur-
face. In this case, to achieve higher strength, the friction and upset-
ting pressures should be as high as possible for the constant friction
time. As the friction and wear help to get rid of contaminants like ox-
ide on the interface, a new face should be surfaced. At the same time,
the upsetting and friction pressure and friction time set in to bring the
new face within the scope of attraction range [14, 15].
Fig. 4. Tensile test sample macrograph of fractured surface.
EFFECT OF FRICTION TIME ON MICROSTRUCTURE AND PROPERTIES OF STEEL 247
3.3. Microstructure
Figure 5 shows the typical microstructural features of the welded sam-
ples. As seen from the macrographs, flash formation was observed in all
welded samples because of plastic deformation during welding. Friction
Fig. 5. Typical macro- and microstructure of the friction welding parts; P1 =
= 40 MPa, P2 = 60 MPa, t = 3 s (a), 5 s (b), 7 s (c).
248 Hakan ATES and Nihat KAYA
time plays an important role in flash formation, which gets bigger with
increasing friction time on both sides of materials due to the higher heat
input and extensive plastic deformation. Thus, the burn-off (axial
shortening) increases with the increase of plastic deformation (see
Figs 5, a, c). All of the welded joints were perfectly bonded and free of
any crack, pore and defect.
Two main regions are observed on the welded samples: a dynamically
recrystallized zone with extremely fine grains and plastically deformed
heat affected zone (see Figs. 6, a—c). The width of both zones changes due
to the materials properties, i.e. yield strength, coefficient of thermal ex-
pansion (CTE), and ductility. Low yield strength, high heat conductivity
and high ductility at elevated temperatures causes more deformation of
the AISI 1060 side compared with AISI 304 side. Thus, deformation that
is more plastic, extended HAZ and more axial shortening were observed
on AISI 1060 side and these properties expanded with increased friction
time. Figures 6, a—c also show the grain orientation inside the HAZ
zones. The intensity of orientation depends on the welding parameters
[11]. It is clearly seen that sufficient friction time on the joining surface
resulted in an adequate locking of the surfaces, where extensive plastic
deformation and microstructural changes occurred, and these facts
Fig. 6. The effect of friction time on deformation zone: 3 s (a), 5 s (b), 7 s (c).
EFFECT OF FRICTION TIME ON MICROSTRUCTURE AND PROPERTIES OF STEEL 249
caused better tensile response of the joint, where recrystallization oc-
curred on the AISI 1060 side (higher deformation) and grain refinement
and strain hardening occurred on the AISI 304 steel side (lower defor-
mation). The width of recrystallized zone is mainly affected by the fric-
tion time. An increase in the friction time results in wider size of fine
grain region. The change of microstructure and higher axial shortening
is also observed in the AISI 1060 side.
Heat flow is observed preferentially in the material with the higher
thermal conductivity. Due to the different thermal conductivities of
AISI 304 (16.2 W⋅m−1⋅K−1) and AISI 1060 (49.8 W⋅m−1⋅K−1), the specific
heat was so large, and hence most of the frictional heat generated in the
AISI 1060 side. The difference in thermal conductivity explains the mi-
crostructural changes, which occur preferentially in the AISI 1060 side.
Similar microstructural observations for the Cu—Ti couples were also re-
ported in [16]. Most of the changes took place in the copper, no evidence of
microstructural variation was seen in the vicinity of the interface, and
neither grain growth nor grain boundary precipitation was observed. This
behaviour can be attributed to the difference of thermal conductivity [16].
Figures 5 and 6 also show the microstructural changes of AISI 304
side and AISI 1060 side of weld. During the friction welding process,
the temperature near the welding interface reaches just above A1 tem-
perature, which is almost equal to the recrystallization temperature
for the steel. Therefore, extremely fine equiaxed grains formed from
ferrite and pearlite. Martensitic structure could also be seen in this re-
gion, when the welding interface reaches A3 temperature with the oc-
currence of rapid cooling. Therefore, the microstructure of AISI 1060
steel turned into austenite. When austenitic structure was exposed to
top cooling from evaluated temperatures, the microstructure turned
into martensite due to the diffusion of carbon to the grain boundary
and rapid cooling rate. These results mean that the weld experienced
different thermal histories. The relatively quick cooling rate influ-
enced the microstructure of the weld.
Figures 7 (1) and (2) show energy dispersive spectroscopy (EDS)
analysis points observed on the AISI 304 side, while (4) and (5) show
EDS analysis points observed on the AISI 1060 side. It is seen that al-
loying element concentration significantly changed at the joint surface
(Point 3) and adjacent to the Point 3 due to the mechanical locking and
atomic diffusion. In the joint surface Cr (1.53%) was measured for 3 s
friction time. However, the increase of the friction time caused high
density of Cr in the surface, where more heat generated as a result of
high friction pressure. It is obvious that Cr atoms with smaller diame-
ter are more mobile and diffusive inside this region. Significantly high
amounts of Cr and Ni are detected on the AISI 1060 side in Point (4)
and (5) under all conditions. Çelikyürek et al. [17] have reported the
same phenomenon for Fe—28Al and 316 L SS.
250 Hakan ATES and Nihat KAYA
Fig. 7. Joint surfaces and location of the EDS analysis sites. The effect of fric-
tion time on the elemental distribution.
EFFECT OF FRICTION TIME ON MICROSTRUCTURE AND PROPERTIES OF STEEL 251
High amount of Al, Cr, and Ni atoms were diffused into interface
and HAZ region due to the long period of friction time.
4. CONCLUSIONS
Based on the results obtained in this study, the following conclusions
could be drawn.
1. Friction welding can be used successfully to join austenitic stainless
steel (AISI 304) to AISI 1060 structural steel. The processed joints ex-
hibited better mechanical and metallurgical characteristics.
2. The highest hardness values were observed in the interface, but they
significantly varied with increasing distance and friction time. The
increase in the hardness at the joint zone may be attributed to the mi-
crostructural evaluation.
3. The tensile strength of friction-welded joints was not affected by
friction time. The tensile strength of obtained weld joints can exceed
AISI 304 SS strength by 30%. Fracture usually occurs in the HAZ of
AISI 1060 steel side.
4. An extensive deformation occurred mostly to the AISI 1060 side due
to its flow stress and high thermal conductivity.
5. Typical microstructural features were observed in the welding re-
gion. Recrystallized fine and elongated grains were observed near the
joint surface. The width of recrystallized region is mainly affected by
the friction time.
6. The variance in weight of alloying elements is seen from analysis of
elements spectra. EDS measurements clearly show that steel joints
consist of different crystal structure, carbides and intermetallic com-
pounds. Diffusion of the Cr and Ni is observed in the AISI 1060 side.
ACKNOWLEDGEMENTS
The authors wish to thank Prof. Dr. A. Kurt, Prof. Dr. N. Kahraman
and Prof. Dr. I. Uygur for their invaluable contribution. Also special
thanks to Turkish Track Factory for their support and guidance during
the experimental stage.
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