7 results listed
In this study, isothermal annealing was performed to
C70 quality steel sheet in a salt bath at 250 °C and 350 °C for 10 s,
1 min, 10 min, and 60 min after austenitizing performed at 850 °C
for 150 s and the samples were then tempered at 415 °C for 150 s.
Effect of these heat treatments on microstructure, hardness and
bending properties was then investigated. Results showed that the
initial ferrite and pearlite microstructure generally transformed
into martensite. Tempered martensitic microstructure was
obtained after tempering heat treatment. Hardness of the samples
has a decreasing tendency with increasing annealing times at a
given annealing temperature. Tempering heat treatment
decreases the hardness values obtained after isothermal
annealing, as expected. However, hardness values after tempering
did not exhibit a significant variation with respect to isothermal
annealing time. As compared to original sample, the application
of tempering after isothermal annealing increases bending
strength, and bending strain also increases getting closer to values
exhibited by the original sample.
International Iron & Steel Symposium
UDCS
Serdar Kuzkaya
Yakup Yurekturk
Faiz Muhaffel
Murat Baydogan
Hot work tool steels are generally used in plastic
forming processes of metals as extrusion dies and punches. Service
life of these parts are related to their surface defects and
dimension changes arising from exposure to high pressure and
wear at high temperatures during plastic forming. Therefore, it is
important to enhance the surface properties of these parts to
extend their lifespan and mitigate the consequences of surface
defects and wear damage. Simulating damages on the dies
occurring during their service period is critical to estimate their
lifetime.
A homemade impact-sliding wear testing machine was designed
and used for accelerated simulation for observing performance of
quenched and tempered hot work tool steels in laboratory. Impact
sliding wear tester can be used for simulating extrusion process to
evaluate wear performances of different kind of die materials used
for metallic component production.
In the scope of this study, two different kinds of hot work tool steel
A and B were quenched and tempered with the carbon equivalent
of 1.91 and 1.66 respectively. Structural features of hot work tool
steels were characterized by optical microscopy, scanning electron
microscopy, X-Ray diffractometer and hardness measurements.
Furthermore, sliding and impact sliding wear tests were
conducted at room temperature (RT) to evaluate their wear
performances. Wear tracks were examined by profilometer to
compare wear damages of the steels. Results of characterization
analyses showed that steel A with the carbon equivalent of 1.91
sample exhibited better resistance against impact sliding wear
compared to steel B with the carbon equivalent of 1.66.
International Iron & Steel Symposium
UDCS
Ezgi Akyıldız
Faiz Muhaffel
Mert Altay
Seçkin Özkurt
Erdem Atar
Huseyin Cimenoglu
In metal forming process, improving mechanical and
surface properties of tool steels has been significant issue, since the
productivity is mainly related with the service life of tools. In order
to enhance service life of tools, wear is the most challenging
problem to tackle due to its detrimental effects on surface and
dimensional characteristics of components especially produced by
hot forming process. In the present study, influence of nitriding on
the wear resistance of famous AISI H13 tool steel was investigated
by homemade impact-sliding wear tester to simulate forces which
affects tool steels during extrusion process. Structural
characterization of nitrided and bare samples via using X-ray
diffractometer, optical and scanning electron microscopes was
conducted along with hardness measurements. Wear tracks of
samples subjected to impact-sliding wear test at room and
elevated temperature were examined under scanning electron
microscope in order to determine their wear mechanism. 2-D
profilometer was also used to measure the wear loss.
Results of these examinations revealed that nitriding leads to
increment in impact-sliding wear resistance of H13 tool steels at
room and elevated temperature.
International Iron & Steel Symposium
UDCS
Belda Aydın
Birsen Baş
Mertcan Kaba
Mert Altay
Faiz Muhaffel
Utku İnan
Seçkin Özkurt
Erdem Atar
Huseyin Cimenoglu
H13 (DIN-X40CrMoV) is one of the well-known steels for utilization at elevated temperatures owing to its good resistance to softening at high
temperatures and thermal shock resistance along with a relatively low cost. In the present study, sliding wear performance of H13 hot work tool
steel at room and elevated temperatures has been examined against Al2O3 ceramic counter-material. Based on the observations and analyses of
the contact surfaces, wear track profiles, and friction curves, the role of varying temperatures on the operative wear mechanism has been
examined.
International Iron & Steel Symposium
UDCS
Zafer Can TEOMAN
Faiz Muhaffel
Huseyin Cimenoglu
Mg and its alloys are commonly used in automotive, aerospace, biomedical, communication industries due to
their superior properties such as high specific strength, low density, good electromagnetic shielding, superior damping
capacity, machinability and recyclability. Nonetheless, low wear and corrosion resistances are the main drawbacks
limiting extensive usage of magnesium alloys. Moreover, low melting point of magnesium limits wide-range of
applications at elevated temperatures [1,2].
International Symposium on Light Alloys and Composite Materials
UHAKS
Ekin Selvi
Faiz Muhaffel
Murat Baydogan
Weight reduction in vehicles is nowadays a critical concern for automotive industry and many different
approaches are attempted to reduce fuel consumption and CO2 emission [1]. Therefore, use of lightweight aluminium
alloys exhibiting properties such as high specific strength compared with that of steels and good capability of being heat-
treated to improve their mechanical properties, rapidly increase in many different automotive applications. 6082
aluminium alloy is one of the most widely used medium strength aluminium alloys with good corrosion resistance. It has
the highest strength of the 6000 series alloys which mainly contain magnesium, silicon and manganese as alloying
elements. The addition of a large amount of manganese controls the grain structure which in turn results in a stronger
alloy. However, corrosion resistance often decrease the lifetime of the 6082 alloy in harsh corrosive environments. Thus,
some surface engineering techniques are generally required to extend the use of aluminium alloy components.
Micro arc oxidation (MAO) has been used in recent years as an emerging environmentally friendly technique
for preparing oxide coatings on light metals to restrict the directly contact with environment [2]. MAO of aluminium
alloys generates a thick alumina dominated ceramic coating on surface of the alloys with the aim of protecting surface
from wear- and corrosion-induced failures [3].
International Symposium on Light Alloys and Composite Materials
UHAKS
Mehmet Ragip Muhaffel
Faiz Muhaffel
Huseyin Cimenoglu
Titanium and its alloys are attractive biomedical materials for load bearing implants such as hip and knee
prosthesis due to their high strength, good corrosion resistance, low density and enhanced biocompatibility. Among
titanium alloys, Ti6Al4V alloy occupies about 50% of total world titanium market. The good biocompatibility of titanium
alloys can be attributed to the nano-scale titanium oxide layer formed naturally on the surface of the alloy in oxygen
containing environment. Although Ti6Al4V alloy along with its good properties are still favourable for biomedical
applications, toxicity of vanadium, which is present in Ti6Al4V alloy at about 4 wt.%, raises some concerns about health
issues [1]. To overcome this drawback, Ti6Al7Nb alloy has been fabricated by substituting of vanadium with 7 wt.%
niobium and aimed to achieve similar mechanical and biological properties.
International Symposium on Light Alloys and Composite Materials
UHAKS
Faiz Muhaffel
Huseyin Cimenoglu