SEARCH RESULT

In recent years, the use of Modern Maintenance Management Systems (MOBAYS) has an important place to optimize maintenance costs and increase efficiency in enterprises, factories, hospitals etc. In this study, applicability and usage performance of WEB-based MOBAYS to rail profile rolling plant was investigated. As a short brief; at the end of the usage of the MOBAYS Modern maintenance management system at the rail profile rolling plant; the rate of periodic maintenance %78.26 and the network rate %8.71 increases and in addition to this the unit stoppages %24.06 decreases, were detected.

International Iron & Steel Symposium
UDCS

Semih DOĞAN Hasan GÖKKAYA Ahmet Fatih YILMAZ

AISI 304 stainless steel accounts for approximately 50% of the world's stainless-steel production and consumption. It is important to improve the machinability properties of stainless steels due to the intensive use in the industry. In this study, the effect of machining parameters on surface roughness was investigated in water jet turning of AISI 304 material. The test parameters were determined as nozzle feed rate, abrasive flow rate, turning speed of the chuck and nozzle distance. During the experimental study, the pump pressure (380 MPa), the abrasive size (80 Mesh in Garnet form) and the nozzle diameter (0.75 mm) were kept constant. According to the experimental results, the surface roughness decreased as the turning speed and the abrasive flow rate increased. On the other hand, the surface roughness value increased as the nozzle feed rate and nozzle distance increased.

International Iron & Steel Symposium
UDCS

Fuat KARTAL M. Hüseyin ÇETİN Hasan GÖKKAYA

In this study, at Kardemir Co. Inc., during the absorption of BOF gas with basic oxygen furnaces (BOF) in the steel production phase with high suction ID fan (Induced Draft), it was provided that wear of the ID fan blades was improved. As a result of the investigations, it was determined that BOF gas eroded ID fan body and wings and an increase in ID fan vibration values due to abrasion happened. ID fan blades have been improved to eliminate wear on ID fan blades. As a result, improvements have resulted in reduced production stoppages due to vibration, improved production efficiency and reduced production costs.

International Iron & Steel Symposium
UDCS

Halil İbrahim EMİROĞLU Hasan GÖKKAYA Ahmet Fatih YILMAZ

In this study, at Kardemir Co. Inc., during the absorption of BOF gas with basic oxygen furnaces (BOF) in the steel production phase with high suction ID fan (Induced Draft), it was provided that wear of the ID fan blades was improved. At the end of the wear improvement work, the ID fan blades are plated with AISI 304L stainless steel to remove the wear on the ID fan blade wings. Briefly, improvement of the ID fan blades with the AISI 304L stainless steel, a decrease in the production stops time during the steel production phase with BOF so depending on the decrease, steel production has increased.

International Iron & Steel Symposium
UDCS

Halil İbrahim EMİROĞLU Hasan GÖKKAYA Ahmet Fatih YILMAZ Abdullah UĞUR

—A non-conventional material removal process, Abrasive Water jet (AWJ) machining is also an ideal manufacturing process for very hard materials. This study aims to optimize the parameters involved in AWJ machining of 316 stainless steel material such as abrasive material grain size, nozzle speed, standoff distance, abrasive mass flow rate and pumping system pressure. The analysis of the impact of parameters involved in this study was conducted using the L27 Taguchi orthogonal array, S/N ratio and ANOVA. Five controllable factors were used to obtain the minimum surface roughness and each parameter was assigned with three different values in order to define the optimal factor and level combination. Results showed that the surface roughness is in strong correlation with abrasive material grain size. The findings of this study suggest that the study design used is much more effective than the full factorial design in terms of the number of experiments conducted.

International Iron & Steel Symposium
UDCS

Fuat KARTAL Hasan GÖKKAYA

This study investigates the impact of processing parameters on the surface roughness in the process of abrasive water jet. The sample was machined using abrasive water jet for four different parameters of Nozzle feed rate (5, 15, 25 and 35 mm/min), abrasive flow rate (100, 150, 200 and 250 g/min), spindle speed (50, 100, 150 and 200 rpm) and nozzle distance (2, 6, 10 and 14 mm). Pump pressure (380 MPa), abrasive size (80 Mesh, in Garnet form), and nozzle diameter (0.75 mm) are kept constant throughout the empirical study. According to the results obtained from the experiment, increasing machining parameters, namely nozzle feed rate and nozzle approach distance, resulted in increased average surface roughness. On the other hand, increased spindle spin and abrasive flow rate result in enhanced average surface roughness (Ra).

International Iron & Steel Symposium
UDCS

Fuat KARTAL Hasan GÖKKAYA

Inconel 718 is commonly sought after for its resistance to high temperature and corrosion, however, these characteristics reduce the machinability of this material which brings forth the AWJ machining, a non-conventional material removal process, as the ideal option. The use of Abrasive Waterjet (AWJ) machining for Inconel 718 offers desired machining characteristics, therefore, has a commercial significance. The objective of this study is to optimize input parameters of AWJ machining involved in AWJ machining of Inconel 718 using the Taguchi technique. Optimization of AWJ machining parameters was conducted based on the analysis of variance (ANOVA) and Signal-to-Noise (S/N) Ratio analysis in order to obtain effective Surface Roughness and Material Removal Rate. AWJ machining parameters such as abrasive flow rate, focusing tube size, traverse speed and water pressure were calculated for optimized Surface Roughness and Material Removal Rate. It was concluded that the optimal AWJ machining parameters found in this study are satisfactory for the actual/commercial machining of Inconel 718.

International Iron & Steel Symposium
UDCS

Fuat KARTAL Hasan GÖKKAYA Refik POLAT

In this paper, Taguchi technique is selected in order to explore ideal process parameters for abrasive water jet machining (AWJM). The goal of this exploratory research is to explore the effects of machining parameters on MRR and SR of a work piece made of aluminum a356 alloy. Our approach is based on Taguchi's technique, ANOVA and the SN ratio in order to optimize AWJ machining process parameters for successful machining and to establish optimal values of each AWJM parameter, namely, abrasive stream rate, traverse speed, standoff distance and abrasive grit size. L9 orthogonal array is utilized for varying values of A, B, C, D and three tests were conducted for each combination. Using the SN ratio, it was possible to find the optimal parameter values for AWJM. It was concluded that, in actual practice, the ideal combination of AWJM process parameters fulfill the requirements for machining of cast A 356 aluminum alloy.

International Iron & Steel Symposium
UDCS

Fuat KARTAL Hasan GÖKKAYA Refik POLAT

The influence of microwave absorbing properties of polyvinyl butiral (PVB)/BaTiO3 composites were investigated in the 1-14 GHz. PVB/filler particles (BaTiO3) composites were prepared with 85/15, 90/10 and 95/5 mixture ratios via Ultrasonic Probe Sonicator method in solution. The complex permittivity (ε’- jε’’) and permeability (μ’- jμ’’) of the composites have been measured at different microwave frequencies in 1–14 GHz employing vector network analyzer (Keysight N9926A). The reflection loss (RL) of composites was calculated and evaluated using the theory of the absorbing wall. The results show that absorption is increasing as the fillers rate increase and thickness is decreased. This can be understood based on quarter wave principle within the frequency range from 1 GHz-14 GHz for different thickness.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Yuksel Akinay Fatih HAYAT Hasan GÖKKAYA

The milling of carbon fiber reinforced polymers (CFRP) is a challenging process due to the non-homogeneous, anisotropic structure and extreme hardness of this type of material. Tool wear occurring during the machining process and the resulting failure mechanisms including delamination, matrix and fiber breakage have severely adverse effects on surface quality of machined products. Since deterioration of machined surface quality may impair the strength of components, particular importance is attached to this situation especially in aviation industry. As a failure mechanism arising from the machining of the materials, this situation may result in timeless damages on critical components, such that, almost 60 % milled CFRP components are discarded due to delamination-related damages. In this context, investigation of the failure mechanisms resulting from delamination and delamination-related situations arising during the milling of CFRP composites was aimed in the present research.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Dervis Ozkan Mustafa Sabri Gök Hasan GÖKKAYA Abdullah Cahit KARAOGLANLI

The effects of cutting parameters which are used in CO2 laser machines on surface roughness of AISI 304 quality stainless steel sheet after cutting process is examined in this study. 3 mm AISI 304 quality stainless steel is prepared with the help of a determined geometrical model by cutting. In processing experiments, parameters are divided into two sections as constants and variables. Frequency, Duty, Nozzle, Material, Speed and Lens parameters are kept as constant, Power, Focus, Pressure and Substitute Gas parameters are kept as variable. The experiments were carried out in accordance with the full factorial experiment. The average surface roughness values was measured after cutting experiments and evaluated by ANOVA (Analysis Of Variance) variance analysis. The measured average surface roughness values ranged from 1.261 to 4.156 µm. The parameters of power, pressure and auxiliary gas are affected by surface roughness, Focus distance has not been effective. This study is thought to have an important position to light the way for the companies which take place in production sector.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Murat Tunc Gökhan Sur Hasan GÖKKAYA Muammer Nalbant

Carbon fiber reinforced plastic (CFRP) composite materials, among other fiber reinforced materials, exhibit excellent resistance properties against a low specific weight. They have been used in a wide range of contemporary applications particularly in aerospace industry, defense, automotive, machine tools, sports equipment, transportation structures, power generation, oil and gas industry. Various damage mechanisms such as fiber pull-out, fiber break, matrix smearing and delamination damage have been observed in CFRP composite materials in their work. In this study, CFRP composite materials in direction 0º, 45º and 90º were produced by the vacuum bagging method. CFRP composite materials were drilled at different parameters with abrasive water jet (AWJ) machining center. Delamination damage were analyzed.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Meltem Altin Karatas Hasan GÖKKAYA

In the present research on milling of carbon fiber reinforced polymer (CFRPs) composites widely used in aviation industry, the effects of different cutting speeds and feed rates on the surface roughness was investigated using tungsten carbidecobalt based (WC-Co) carbide cutting tools. A CFRP composite with 6 mm thickness and 24 layers was used as the work-piece. The tests were performed on a CNC vertical processing center with 100, 200 and 300 m/min cutting speeds, 0.05-0.15 and 0.25 mm/tooth feed rates and 1 mm constant cutting width under dry conditions. Following the tests, the surface roughness of the work-piece was investigated. 5.7 µm surface roughness was obtained with 100 m/min cutting speed and 0.25 mm/tooth feed rate.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Dervis Ozkan Mustafa Sabri Gök Hasan GÖKKAYA Abdullah Cahit KARAOGLANLI

The usage areas of carbon fiber reinforced plastic (CFRP) composite materials are increasing day by day in various industries due to their manufacturability in varying combinations with customized strength properties, also their high fatigue, toughness and high temperature wear and oxidation resistance capabilities render. Some of the damage mechanisms have been observed in CFRP composite materials as well as in other anisotropic and inhomogeneous materials in their work. In this study, CFRP composite materials in direction 0º, 45º and 90º were produced by the vacuum bagging method. CFRP composite materials were drilled at different parameters with abrasive water jet (AWJ) machining center. Surface roughness were analyzed.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Meltem Altin Karatas Hasan GÖKKAYA

Sandwich panels have been widely used in several fields due to their mechanical properties. In this research, the effect of core edge curvature of sandwich panels on their impact performance was examined. In this regard, sandwich panels were modelled for seven different radius of edge curvature (0,5:1:1,5:2:2,5:3:3,5 mm). Al 2024 was used as the face-sheet and core material. Quasi-static impact analysis was carried out using Abaqus finite elements software at 1 m/s test speed and under 8 tons test load. Analysis results revealed that, the use of different edge curvature values affected the mechanical properties such as the amount of absorbed impact energy, maximum peak force and the average crushing force. In conclusion, the amount of absorbed energy increased and the peak force decreased with increasing radius of edge curvature. On the other hand, sandwich panel’s resistance against vertical loads was reduced when the change in curvature resulted in a reduction in the length of the core wall by more than 50%.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

E. ZURNACI Hasan GÖKKAYA

In this study, the super alloy Hastelloy C22 abrasion process was conducted with a copper electrode in electro erosion machine tools. The parameters used in the experimental study were three different pulse durations (10, 20 and 30 μs), waiting time (5, 10 and 15 μs) and discharge currents (5, 10 and 15 amps). As a result of the work done, the minimum mean surface roughness value was measured as 20 μs in the pulse duration, 10 μs in the wait time and 2.86 μm in the 5 amp current. The highest average surface roughness value was found to be 10 μs, 10 μs in the waiting period and 4.07 μm in the 15 amperes current.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Engin Nas Hasan GÖKKAYA Sitki Akincioglu Gulsah Akincioglu

In this study, Deep cryogenically treated (-145 ᵒC) (H0) and untreated Hastelloy C22 Super Alloy (H1) were etched with a copper electrode on an electro erosion discharge. The parameters used in the experimental study were determined as three different durations (10, 20 and 30 μs), waiting time (5, 10 and 15 μs) and discharge currents (5, 10 and 15 amperes). As a result of the work done, the lowest surface roughness value was measured as 2.20 μm in 20 μs sweep time, 10 μs waiting time and 10 amperes current.

International Conference of Advanced Materials and Manufacturing Technologies
ICAMT

Engin Nas Sitki AKINCIOGLU Hasan GÖKKAYA Gulsah AKINCIOGLU