Bekir Sadık Ünlü

Investigation of tribological properties of boronised pure Cu journal bearings

Abstract Cu based materials are widely used as journal bearings. These materials have a good tribological performance in journal bearings. Pure copper is not generally used due to its low mechanical and wear properties. It is generally used as alloys. In this study, tribological properties of copper bearings manufactured from pure copper were investigated by boronising at 950°C. The SAE 1050 steel shaft was used as counter abrader. Experiments were carried out at 20 N load and 1500 rev min–1 speed every 30 min for 2·5 h using radial journal bearing wear test rig. As a result, boronising increased wear resistance.

Tribological behaviors of polymer-based particle-reinforced PTFE composite bearings

In this study, tribological behaviors of polymer-based particle-reinforced PTFE bearings have been investigated and evaluated. Tribological properties of these particle-reinforced PTFE composite bearings have improved two- or three-fold.

Tribological properties of boronized ferrous based PM journal bearings

Abstract 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-graphite 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.

Microstructural Properties of Particle-Reinforced Polytetrafluoroethylene Composite Bearings After Wear

High-performance engineering polymers that ensure the desired properties of journal bearings and give good wear results are investigated. We determine the microstructural properties of polymer-based particle-reinforced polytetrafluoroethylene composite bearings by analyzing the optical and SEM surface wear images.

Effect of Boronizing and Shot Peening on the Fatigue Properties of an Iron Based FeCu-Graphite P/M Material

Abstract Iron based materials manufactured by powder metallurgy (P/M) method are widely used in industry. These materials are very important in applications where no machining is required, they can also be used as journal bearing material due to their self-lubricated property, and can be used for applications in the medical industry. In this study, powder metal parts were manufactured from composites based on FeCu-graphite by P/M method. Fatigue test was carried out on manufactured samples, which were only treated by boronizing or boronizing and shot peeing. The fatigue properties of these parts were investigated by a rotating bending fatigue test rig.

Investigation of the Element Diffusion in Friction Welded X53CrMnNiN219 and X45CrSi93 Steels

Abstract In this study, high alloyed steel bars with a diameter of 12.30 mm made up of 1.4871 (X53CrMnNiN219) and 1.4718 (X45CrSi93) steels were used as experimental material for friction welding. Metallographic and X-ray diffraction investigations as well as microprobe sampling were performed on the samples. Mechanical orientation of particles caused by plastic deformation and carbide scattering has been observed. The diffusion behaviour has been investigated for the elements Cr, Ni, Mn, and Si, respectively. The existence of (Cr,Fe)7C3 carbides in the welding region was also observed.

Tribological Properties of Sn-Pb Based SnPbAlZn Journal Bearings

Abstract Tin and lead based alloys are widely used as journal bearing materials in tribological applications. If Al or Zn with their sliding property will be added to such materials the tribological properties of journal bearings can be improved once more. In this study, wear properties of these journal bearings manufactured from SnPbAlZn, pure Sn, pure Pb, pure Al, and pure Zn bearings were investigated. Experiments were carried out in every 30 min for the total of 150 min by using radial journal bearing wear test rig. As a result wear properties can be improved by variation of SnPbAlZn material.

Determination of tribological properties at CuSn10 alloy journal bearings by experimental and means of artificial neural networks method

Purpose – It is important to know the friction coefficient and wear loss for determination of tribological conditions at journal bearings. Tribological events that influence wear and its variations affect experimental results. The purpose of this paper is to determine friction coefficient and wear loss at CuSn10 alloy radial bearings by a new approach. In experiments, effects of bearings have been examined at dry and lubricated conditions and at different loads and velocities.Design/methodology/approach – In this study, friction coefficient and wear losses of journal and bearing have been determined by a new approach with a radial journal bearing test rig and artificial neural networks (ANNs) method. The ANN typifies a learning technique that enables the hidden input‐output relationship to be mapped accurately. Bronze‐based materials have been used as bearing material. Effects of friction coefficient and wear losses have been examined at same load and velocity and at dry and lubricated conditions.Findings...