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    Mechanical properties of P/M 316L stainless steel materials
    (Elsevier Science Sa, 2010) Kurgan, N.; Varol, R.
    In this work, 316L stainless steel (SS) powder was used. The composition of the powder is as follows: 0.015% C, 1.75% Mn, 0.45% Si, 17.24% Cr, 2.79% Mo, 14.65% Ni, and balance iron. Mixed powder was compressed cold using single action press under 800 MPa pressure. Compressed samples were sintered at 1200 degrees C, 1250 degrees C, and 1300 degrees C into the nitrogen gas atmosphere. In order to determine the mechanical properties of the produced specimens, the fatigue tests, tensile test, three-point bending test, impact test and hardness tests were applied to the specimens. Determined mechanical properties in the result of this work were compared to the properties as stated in ASTM F138-G2. Besides that to define the microstructures of the produced specimens in detail, metallographic studies were performed. (C) 2010 Elsevier B.V. All rights reserved.
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    Tribological properties of boronized ferrous based PM journal bearings
    (Carl Hanser Verlag, 2015) Ünlü, B.S.; Yilmaz, S.S.; Kurgan, N.; Varol, R.
    Ferrous based PM (powder metallurgical) materials are widely used in journal bearings since they provide a good tribological performance. These bearings are self-lubricating and can be used in places where lubricating is not possible. This also applies to the shaft material which shows adhesive wear. Tribological properties can be improved and adhesive wear can be decreased by boronizing. In this study, tribological properties of ferrous based boronized and non-boronized Fe-graphite, FeCu-graph-ite and CuSnFe-graphite bearings manufactured by PM method have been determined and compared. Boronizing treatment was carried out at 950°C for 4 hours. The SAE 1050 steel shaft was used as counter abrader. Experiments were carried out at 20 N loads and 1500 rpm every 30 minutes for 2.5 hours. © Carl Hanser Verlag, München. © Carl Hanser Verlag GmbH & Co. KG.
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    Wear behavior of severe shot peened and thermally oxidized commercially pure titanium
    (Springer Verlag, 2019) Unal, O.; Karaoglanli, A.C.; Ozgurluk, Y.; Doleker, K.M.; Maleki, E.; Varol, R.
    In this study, severe shot peening (SSP) has been performed to commercially pure titanium (Grade 2) specimens in order to expose severe plastic deformations to the material surface. S230 shot media with higher air pressure conditions have been selected for SSP. A nanocrystalline layer has been created by means of severe plastic deformation. The nanograined structure has been investigated via XRD, FESEM, and microhardness methods. SSP specimens have been subjected to thermal oxidation treatment in air at 500 and 700 °C for 2 and 16 h. Severe shot peened commercially pure titanium has a thicker oxide layer when compared to as received ones. The results show that both SSP and thermal oxidation improve the wear characteristics. © 2019, Springer International Publishing AG, part of Springer Nature.