2014 Cilt 19 Sayı 2
Permanent URI for this collectionhttps://hdl.handle.net/11452/11686
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Item Evaluatıon of the effects of cutting parameters on the surface roughness during the turning of hadfield steel with response surface methodology(Uludağ Üniversitesi, 2014-04-18) Ekici, Ergün; Uzun, Gültekin; Kıvak, TurgayHadfield steel (X120Mn12) is widely used in the engineering applications due to its excellent wear resistance. In this study, the effects of the cutting parameters on the surface roughness were investigated in relation to the lathe process carried out on Hadfield steel. The experiments were conducted at a cutting speed of 80, 110, 140 m/min, feed rate of 0.2, 0.3, 0.4 mm/rev and depth of cut 0.2, 0.4, 0.6 mm, using coated carbide tools. Regarding the evaluation of the machinability of Hadfield steel, a model was formed utilizing the response surface method (RSM). For the determination of the effects of the cutting parameters on the surface roughness, the central composite design (CCD) and variance analysis (ANOVA) were used. By means of the model formed as a result of the experimental study, it was demonstrated that among the cutting parameters, the feed rate is the most effective parameter on the surface roughness, with a contribution ratio of 90.28%. It was determined that the surface roughness increases with increasing feed rate. With respect to the effect on the surface roughness, the feed rate was followed by the cutting speed with a contribution ratio of 3.1% and the cutting depth with a contribution ratio of 1.7%.Item The golden horn: Heritage industry vs. industrial heritage(Uludağ Üniversitesi, 2015-02-19) Günay, ZeynepThe revitalization of former industrial areas has been one of the crucial tasks of urban policy agenda throughout the world since the mid 1970s; whereas heritage industry has become the new orthodoxy in the shift from production to consumption as means for the restructuring and reimaging of post-industrial economies in the global order. The increasing tendency to link heritage and conservation with economic development has brought new meanings to cultural assets, the value of which has started to be related solely to the economic value it sustains or generates. The commodification and instrumentalization of industrial heritage by the heritage industry, in particular, has turned out to be the determining factor for creating opportunity spaces in the post-industrial areas. At the same time, many academics are critical on the attempts to reform post-industrial spaces of consumption with privatized spaces and commodified cultures. Within this context, the paper attempts to evaluate the role and the impact of heritage industry in the revitalisation of the post-industrial spaces of Istanbul, with a case study on the Golden Horn. The results of the paper are related to the following questions: What role the industrial heritage play in the revitalisation of historic environments? What are the ways to turn such industrial heritage into sources of social and economic development? What are the likely impacts on the local economy and local community? The conclusion gives an overview of the extent of the impacts that industrial heritage has on the Golden Horn, and in turn relates this back to the wider idea of heritage industry being promoted for the urban policymaking in Istanbul.Item Numerical investigation of surface roughness effects on the flow field in a swirl flow(Uludağ Üniversitesi, 2014-03-27) Sakin, Ali; Karagöz, İrfan; Uludağ Üniversitesi/Mühendislik-Mimarlık Fakültesi/Makine Mühendisliği Bölümü.The aim of this study is to investigate axial and tangential velocity profiles, turbulent dissipation rate, turbulent kinetic energy and pressure losses under the influence of surface roughness for the swirling flow in a cyclone separator. The governing equations for this flow were solved by using Fluent CFD code. First, numerical analyses were run to verify numerical solution and domain with experimental results. Velocity profiles, turbulent parameters and pressure drops were calculated by increasing inlet velocity from 10 to 20 m/s and roughness height from 0 to 4 mm. Analyses of results showed that pressure losses are decreased and velocity field is considerably affected by increasing roughness height.Item The performance evalution of ceramic and carbide cutting tools in machining of austemepered ductile irons(Uludağ Üniversitesi, 2014-11-24) Işık, Yahya; Uludağ Üniversitesi/Teknik Bilimler Meslek Yüksek Okulu.The aim of this research is to compare TiN (PVD) coated Al2O3+Ti[C,N] mixed alumina-based (KY4400) ceramic and CVD coated carbide TiC+AI2O3+TiN (ISO P25) cutting tools in turning austempered ductile irons. Ductile cast iron samples were austenitized at 927°C and subsequently austempered for 1 hour at 400°C. The hardness of the workpiece material was measured and found to be 43.5 HRC. In the present work a series of tests were conducted in order to evaluate the tool performances by adopting tool life. In all experiments cutting forces, flank wear and surface roughness values were measured throughout the tool life. No cutting fluid was used during the turning operations. Study of the tool life and failure modes shows that tool life was determined by the flank wear and surface roughness generated on the workpiece. The main conclusion is that tool life of ceramic insert was longer than the coated carbide insert although much higher cutting speeds were used.