Makina Mühendisliği
https://hdl.handle.net/20.500.12508/43
Mechanical Engineering2024-03-29T15:03:58ZInvestigation of the wear behavior of FeNi36 alloy cut by WEDM method under different loads
https://hdl.handle.net/20.500.12508/3036
Investigation of the wear behavior of FeNi36 alloy cut by WEDM method under different loads
Ceritbinmez, Ferhat; Kanca, Yusuf; Tuna, Ahmet; Kanca, Erdoğan
PurposeFeNi36 (Invar-36) alloy is widely used in the fabrication of molding tools in aerospace industries but there remains a need to improve its wear and friction performance due to its relatively low hardness. The formation of a heat affected zone (HAZ) on the surface of Invar-36 cut by wire electric discharge machining (WEDM) is promising to enhance its tribological properties. This study aims to investigate the tribological performance of WEDM-treated Invar-36 via a ball-on-disk tribometer in dry-sliding conditions.Design/methodology/approachThe untreated and WEDM-treated Invar-36 surfaces were reciprocated against an alumina ball at a sliding velocity of 40 mm/s, a stroke length of 10 mm and a sliding duration of 125 min under loads of 5, 10 and 20 N. The worn surfaces were characterized using a 2D profilometry and a scanning electron microscope equipped with energy-dispersive spectroscopy.FindingsThe results showed that the WEDM-treated surface had a superior friction coefficient and wear resistance in comparison to the untreated surface, due to the grown HAZ. There was found to be a 9.3%-11.4% decrease in the friction coefficient and a 47%-57% reduction in the wear volume after the WEDM treatment. Both the untreated and WEDM-treated Invar-36 surfaces found abrasion and plastic deformation as the dominant wear mechanisms.Originality/valuePrevious works have not focused on the tribological performance of the WEDM-treated Invar-36 extensively used for molding tools in aerospace industries. Our findings provide compelling evidence that the WEDM treatment improved the wear and friction performance of Invar-36 alloy because of the grown HAZ.
2023-01-01T00:00:00ZThe effect of hexagonal boron nitride nanopowders addition on the mechanical behaviors of basalt fabric reinforced composites
https://hdl.handle.net/20.500.12508/3016
The effect of hexagonal boron nitride nanopowders addition on the mechanical behaviors of basalt fabric reinforced composites
Gümüş, Fatma Bakal; Yapıcı, Ahmet
PurposeThe purpose of this paper is to investigate the effect of doping element on the structural, thermal properties, mechanical performance and the failure mechanism of hexagonal nano boron nitride (h-BN)-reinforced basalt fabric (BF)/epoxy composites produced by hand lay-up and vacuum bagging technique. h-BN particles doped to composite materials increased the tensile, bending and impact strength of the composite at certain rates while 1 Wt. % h- BN addition shows the highest tensile and flexural strength.Design/methodology/approachThe epoxy resin was doped with h-BN nanopowder at the certain rates (0, 1, 2 and 4 Wt.%) and the epoxy: hardener ratios used in the study were selected as 80%: 20% by weight. Then, with the aid of a roller by hand lay-up method, a mixture of epoxy + hardeners containing nanoparticles and nanoparticle-free were fed onto BFs, 12 layers of each dimension 30 cm x 30 cm. The surplus epoxy resin was moved away from the composite sheets using the vacuum bagging process and left to cure at room temperature for 24 h. ASTM D3039 for tensile, D7264 for three-point bending and D256 for Izod impact test were performed for the mechanical tests. After the tensile test, the morphologies of the fracture surface were examined with a stereomicroscope and various failure mechanisms are highlighted.FindingsIn this study, a series of basalt/epoxy composites with h-BN nanopowders have been prepared to identify the effect of filler ratio on mechanical properties. It has been known from the results of mechanical experiments that the addition of h-BN improves the mechanical performance of materials at a certain rate. The tensile and flexural strengths of h-BN doped composites, increase for concentrations of 1 Wt.% h-BN, but decrease with the increasing content of it. The basalt/epoxy resin composite with higher mechanical properties could be a potential material in the automotive and aerospace industries.Originality/valueThe aim of this study is to contribute to literature within the context of this new combination of composites and their mechanical properties, failure mechanisms. It presents detailed characterization of each composite by using X-ray differaction (XRD), differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy.
2023-01-01T00:00:00ZA Desirability-Based Solution Search Method for Sequential Optimization of the Hot Rolling Process
https://hdl.handle.net/20.500.12508/3010
A Desirability-Based Solution Search Method for Sequential Optimization of the Hot Rolling Process
Çavdar, Faruk; Kanca, Erdoǧan
Although it is an old technique, research on the hot rolling process maintains its importance because of its widespread usage in steel production and its requirement for a vast amount of resources, especially energy. The roll pass design of the hot rolling process considerably affects many operational parameters such as energy requirement, roll wear, working forces, and torques. Furthermore, due to the sequential nature of the rolling process, a design of any number of passes is closely interrelated with all other passes in the process. This complexity makes it challenging to find optimal design solutions that strike a balance between conflicting goals and constraints. In this article, a new optimized solution search strategy based on a desirability function is offered to address the sequential characteristics of the roll pass design. A novel optimization method utilizing response surfaces and the proposed solution search strategy is presented to reduce the shaping energy of the overall process while minimizing turning moments and radial forces on rolls during the rough rolling process. The proposed method provides integrated optimization of the process by ensuring information flow between the passes and can also be applied to other sequential processes with some modifications. The developed method and solution search strategy are illustrated and validated through a case study. The findings of the case study are compared to three distinct pass designs used in industrial power plants. The results show significant energy savings, lower turning moments, and reduced radial forces compared to the reference designs.
2023-01-01T00:00:00ZThe Effects of Using Brass and Copper Wires on the Cutting Quality of Sleipner Cold Work Steel Cut by WEDM
https://hdl.handle.net/20.500.12508/2990
The Effects of Using Brass and Copper Wires on the Cutting Quality of Sleipner Cold Work Steel Cut by WEDM
Ceritbinmez, Ferhat; Kanca, Erdoğan
Wire electric discharge machining (WEDM) is widely used in dies, punches, aerospace and automotive sectors, since materials with high hardness, and temperature resistant, which are not possible to be cut with conventional machining methods, can be cut with high precision using the WEDM method. In this study, cutting speed (mm/min), material removal rate (mm3/min), wire consume (g), machining time (sec), finish measure (mm) and surface roughness (µm) changes as a result of cutting high hardness cold work tool steel using copper and brass wire in WEDM method were investigated. In addition, worn wire and workpiece residues on the machined surfaces were detected by SEM (Scanning Electron Microscope) and EDX (Energy Dispersive X-Ray) analyzes as well as topography and composition were examined. In the case of using copper wire instead of the brass wire, wire consumption and processing time decreased by 23.30 % and 66.29 %, respectively, while MRR increased by 50 % because the copper wire electrode has higher electrical and thermal conductivity than brass wire electrode. In addition, the average dimensional deviation of the parts cut with copper wire decreased from 27 μm to 8 μm compared to the use of brass electrodes, and more precise measurements were obtained.
Anahtar Kelime:
2022-01-01T00:00:00Z