Investigation of surface roughness in
MQL milling of 430 ferritic stainless
steel by using nano MoS2 particle
reinforced cutting fluid
Journal Name:
- Dicle Üniversitesi Mühendislik Fakültesi Mühendislik Dergisi
Keywords (Original Language):
| Author Name | University of Author |
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Abstract (2. Language):
Stainless steel materials are categorized under a
group of materials that are hard to machine due to
high strength, low thermal conductivity and work
hardening tendency during machining. It is possible
that these materials can be machined by using
various cutting fluids, but cutting fluids have
disadvantages such as being harmful to the
environment and health and cost due to using
copiously. In this study, it is intended that the MQL
(Minimum Quantity Lubrication) method is applied
by using nano MoS2 reinforced commercial vegetable
cutting fluid during milling of AISI 430 ferritic
stainless steel material and the sustainable
machining is realized.
Stainless steel materials have been used lots of fields
such as automotive, food, medical, chemistry etc. by
applying machining operations although in spite of
being faced with problems during machining. In
literature, there are a few studies about machining of
stainless steel materials by using MQL method. In this
study, ferritic stainless steel material categorized
under a group of materials that are hard to machine
was milled without being harmful to the environment
by applying MQL method using nanofluid obtained
from mixing commercial vegetable cutting fluid and
nano particles.
Experiments were performed by using First MCV-300
CNC machining center. In experimental studies,
uncoated and TiN (Titanium Nitride) coated WC
(Tungsten Carbide) cutting tools were used. The
stainless steel workpieces were prepared in the
dimensions of 400x250x6 mm.
The slots were machined under dry, MQL with
vegetable cutting fluid, and MQL with nanofluid
conditions. In MQL milling, Werte DKN 25 micro
lubrication system was used and Eraoil KT/2000
commercial vegetable cutting fluid was selected as
lubricant. MQL flow rates were applied as 20 ml/h
and 40 ml/h and spindle speed, feed rate, and depth
of cut were selected as 995 rpm, 180 mm/min, and 0.5
mm, respectively.
The commercial vegetable cutting fluid was
reinforced by nano MoS2 particles to prepare
nanofluid. The nano MoS2 particles were added at
0,5%wt., 1%wt., and 2%wt. Before the addition, nano
particles were dried in Termal G11420SD drying
oven for 2 hours and at 120°C then added to the
vegetable cutting fluid with lecithin which is a
dispersant and added to the mixture to get stable
nanofluid. Daihan WiseTis HG-15D digital
homogenizer was used at 500 rpm to blend the
mixture.
Surface roughness (Ra) measurements of machined
surfaces were performed by Time TR200 surface
roughness tester. The cut-off length was adjusted as
0.8 mm and the resolution of tester is 0.001 μm. Five
measurements were done on each surface and
arithmetic means were calculated.
In the result of milling experiments, it was specified
that the nanofluid MQL method has advantages over
dry milling and MQL method using pure commercial
vegetable cutting fluid. The performance of nanofluid
increased with increase of the amount of nano MoS2
particles in the nanofluid. Additionally, high MQL
flow rate provided that the performance of MQL
method was increased because of supplying high
amount of cutting fluid/pressure air mist.
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Abstract (Original Language):
Paslanmaz çelik malzemeler, otomotiv, gıda, medikal, kimya vb. birçok alanda talaşlı şekillendirme
uygulanarak kullanılmaktadırlar. Ancak bu malzemelerim düşük ısıl iletkenlikleri ve işlem sırasında
gösterdikleri pekleşme eğilimi nedeniyle talaşlı şekillendirilmelerinde zorluklarla karşılaşılmaktadır. Bu
malzemelerin talaşlı işlenmesinde kesme sıvıları kullanılmakta fakat kesme sıvılarının maliyeti arttırması ve
çevre ve insan sağlığı açısından zararlı olması yeni yöntemlerin geliştirilmesini gerektirmektedir. Bu sebeple,
AISI 430 ferritik paslanmaz çeliğin frezelenmesinde, kaplamasız ve TiN (Titanyum Nitrür) kaplamalı WC
(Tungsten Karbür) kesici takımlar ile nano MoS2 (Molibdendisülfür) takviyeli ticari bitkisel kesme sıvısı
kullanılarak MQL (Minimum Quantity Lubrication - Minimum Miktarda Yağlama) yönteminin uygulanması
bu çalışma kapsamında incelenmiş ve sürdürülebilir talaşlı şekillendirilmenin gerçekleştirilmesi
amaçlanmıştır.
Çalışmada, kesme sıvısı olarak kullanılan ticari bitkisel yağa, performansını arttırabilmek amacıyla ağırlıkça
%0,5-%1-%2 oranlarında nano MoS2 parçacıklar katılmıştır. Frezeleme işlemleri, MQL yöntemi uygulanarak
elde edilen sonuçların karşılaştırılabilmesi amacıyla kuru işleme uygulanarak da tekrarlanmıştır. Nano
parçacıkların, katkı oranlarının ve MQL akış hızının frezelenmiş yüzey pürüzlülük değerlerine etkileri
belirlenmiştir.
Frezeleme deneyleri sonucunda, nano akışkan MQL yönteminin kuru işleme ve ticari bitkisel kesme sıvısı
kullanılan MQL yöntemine göre avantaj sağladığı belirlenmiştir. Nano MoS2 parçacık katkı oranının
arttırılmasıyla nano akışkan performansının arttığı belirlenmiştir. Ayrıca, MQL akış hızının arttırılması da
ortama gönderilen kesme sıvısı-basınçlı hava karışım miktarını arttırdığından MQL performansının artmasını
sağlamıştır.
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