AN INVESTIGATION OF THE FRACTURE TOUGHNESS OF C22 WELDED WITH RUTIL COVERED ELECTRODES AND DETERMINATION OF THE MISMATCH FACTOR

Endüstride kullanım sahası oldukça geniş olan C22 çelik sacdan alınan numuneler, farklı çekme dayanımına sahip üç ayrı rutil elektrotlarla kaynak edilmiştir. Yorulma sonucu oluşturulan çatlaklardan hareket edilerek kaynaklı bölgelerin direngenliği araştırılmıştır. Kaynak metali ve Isı Tesiri Altındaki Bölgenin (ITAB) mekanik özellikleri incelenerek kırılma mekaniği parametrelerinden biri olan J(N/mm) kaynak malzemesi tokluk değeri ve Δa(mm) çatlak ilerleme değerlerinin kıyaslanması için grafikler elde edilmiştir. Deney parçası üzerinde boydan boya 4 ayrı bölgeden seçilen çizgilerde kaynak metali, esas metal ve ITAB geçişlerinde mikrosertlik taraması yapılmıştır. Bu çalışmaların amacı esas metal ile kaynak metali arasındaki uyumsuzluğun (mismatch) incelenmesidir. The process of joining of the low carbon steel (C22) which is used in various metal structural industry has been done with the arc welding method by using rutil covered electrodes as filling metal. After the welding process, by examining the mechanical properties and the fracture toughness and crack growth properties of the weld metal, base metal and around of HAZ (Heat-Affected-Zone) of welded specimens, the values of J-Integral and which is one of the fracture mechanics parameters, has been identified. Then the hardness tests on weld metal, base metal and HAZ were obtained at four different location along the longitudinal direction of the specimens. The fundamental aim of this study is to examine the difference of mechanical properties between the weld metal and the base metal (strength mismatched) which affect the deformation and fracture behavior of the welded joints

WEAR RESISTANCE OF POLIESTER- Al2O3 COMPOSITES

Plastik malzeme türleri günden güne artmakta ve bu malzemelerden farklı özellikler elde etmek için kompozitleri üretilmektedir. Kullanımı yaygın bir plastik türü olan polyestere, aşınma dayanımını arttırmak üzere farklı ağırlık oranlarında Al2O3 partikülleri takviye edilerek plastik matriksli partikül takviyeli kompozit malzemeler üretilmiştir. Üretilen kompozit malzemeler Pim-Disk modeli bir aşınma deney düzeneğinde aynı tribolojik şartlarda aşınma deneyine tabi tutulmuştur. Aynı tribolojik şartlar altında aşınma deneyleri yapılan Polyester-Al2O3 kompozitlerinin aşınma dayanımlarının, polyester içindeki Al2O3 oranının artışıyla yükseldiği belirlenmiştir. Aşınma dayanımı ile sertlik arasında bir ilişki belirlenememiştir. The varieties of plastic materials increase day by day and composites of these materials are produced to obtain different properties. Particule reinforced plastic matrix composite materials are produced by reinforcing different weight ratios. Al2O3 particules for increasing wear resistance of polyester, a common by used plastic material. The composite materials produced are subjected to wear experiment in a pin-on-disk model wear experiment setup for equal tribological conditions. It is found that wear resistance of Poliester-Al2O3 composites increase with the increase of Al2O3 ratio. No correlation could be detected between the wear resistance and hardness

AN INVESTIGATION ON THE PRECIPITATION HARDENING OF TIG WELDED 2024 ALUMINUM ALLOY

Bu çalışmada levha şeklinde üretilmiş olan 2024 alüminyum işlem alaşımı 600'lik V kaynak ağzı açılarak TIG kaynak yöntemi ile argon gazı altında ER4043 elektrot kullanılarak birleştirilmiştir. Kaynaklanmış örnekler 492±3 0C'de çözeltiye alınmış ve oda sıcaklığında su verilmiştir, daha sonra bir kısmı doğal yaşlandırılırken bir kısmı da 125 0C'de 22 saat ve 190 0C'de 8.5 saat yapay yaşlandırılmıştır. Kaynaklı örnekler çekme ve çentik darbe deneylerine tabi tutulmuştur. Kaynaklı bölgenin mikrosertliği ölçülüp içyapısı incelenmiştir. In this study, 2024 aluminum wrought alloy manufactured in the form of plates has been welded with TIG welding method under protecting argon gas by using ER4043 electrode as filler metal. The welding geometry is with 600 groove type. The specimens were solution heattreated under 492±3 0C and quenched in water at room temperature. Then, they were aged naturally and artificially. Artificial aging was performed at 125 0C for 22 hours and at 190 0C for 8,5 hours. Natural aging was performed at room temperature for one week. All welding specimens were subjected to tension and Charpy tests. Microhardness and microstructure of the welded specimens were determined

Transmitter localization in vessel-like diffusive channels using ring-shaped molecular receivers

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Molecular communication via diffusion in vessellike environment targets critical applications such as detection of abnormal and unhealthy cells. In this work, we derive the analytical formulation of the channel model for diffusion dominated movement, considering ring-shaped (i.e., patch) observing receivers and Poiseuille flow with the aim of localization of the transmitter cell. Then, we derive formulations using this channel model for two different application scenarios. We assume that the emission start time is known in the first scenario, and unknown in the second one. We successfully localize the transmitter cell using a single receiver for the first scenario, whereas two receivers are used to localize the transmitter cell in the second scenario. Lastly, the devised analytical framework is validated with simulations.Postprint (author's final draft

An Investigation of Deep Drawing of Low Carbon Steel Sheets and Applications in Artificial Neural Networks

In this study, the deep drawability of SAE 6114, being a low carbon steel, was investigated. The materials with thickness varying from 0.67 mm to 2 mm were subjected to tensile tests and then R (average vertical anisotropy coefficient) and n (stain hardening exponent) values were determined. At the same time, h (the height of the cup) and F (the reaction force) values of the materials were found by subjecting them to Erichsen test A sheet with 2 mm thickness was cold rolled in 6 different deformation ratios and the tests were applied to it Results obtained from the tests were compared with each other and ANN application was performed for these results. It was proved that, there was an ANN solution to obtain new values of % deformation rate and thickness properties of deep drawing of low carbon steel sheets which were found by experiment The obtained values satisfied our estimation

THE METALLURGICAL SPECIFICATIONS AND HARDNESS PROFILE OF A RAIL THERMITE WELD

The quality of railroad construction is a important factor for comfort and safety in railroad transportation. Thermite welding being known for a long time prevents rail failure and, off road the train. It provides smoothly journey, and long life to rails and wagons. In this study, S 49 type St 70 steel rails have been welded by thermite process, hardness profile of welding zone rails has been obtained and its microstructure has been examined. In this profile maximum hardness values have been observed in front of welding region. Hardness value was 290 HB in the front of melting zone in the zone under heat effect (HAZ), 260 HB in welding zone and 220 HB in main structure. For microstructure pro-eutectoid ferrite and perlite were observed but not martensite

JOINTING PROCESS OF THE SAE 1020 WITH MAG WELD'S REGION HAVE BEEN INVESTIGATED AND FACTOR OF MISMATCH DETERMINED

In this study, the jointing process of the SAE 1020 low carbon steel, generally used in the industry, has been done by the MAG weld method. The aim of this study is to examine the mismatch between base and weld metal. After the jointing process, mechanical and metalographical properties of the weld region, HAZ, and the weld metal of the samples considered here were searched, and CTOD (Crack Tip Opening Displacement) was identified

Marine parks for protection and tourism in Turkey

Protected Turkish areas in the Mediterranean region are compared with those of other Mediterranean countries. Policies followed in Turkey for conservation protection of the natural and cultural environment and the use of coastal resources for tourism are discussed. The purpose and application of Turkish law is examined with respect to the interaction between the protection of coastal areas and tourism. Modifications on the administrative and management regulations in Turkey enabling a better use of coastal areas is suggested by combining coastal tourism and protection. The necessity and importance of establishing and managing Marine Parks in short- and long-term plans are acknowledged

Application of the Hall-Petch Relation to Microhardness Measurement on AA 1030, Cu, CuSn7, CuZn30 and 6114 Alloys

In this experimental study, the strip formed specimens made from aluminum alloy 1030, pure Cu, CuSn7, CuZn30 and low carbon steel 6114 were cold worked to different ratios. To be able to determine the microhardness values of the materials, the microhardness tests were applied. Grain sizes of the materials were determined by the Heyn method using metal microscope. The hardness of materials H, is dependent on the grain diameter, d, in a similar way as in the flow stress in the Hall-Petch relation: H=H0+KHd-1/2 where H0 and KH are constants. The microhardness of the materials is found to vary with the grain size according to the Hall-Petch equation with reasonable accuracy

INVESTIGATION OF DEFORMATION TEMPERATURES AND STRAIN RATE EFFECTS' ON THE MECHANICAL PROPERTIES OF Al 99.0

The effects of deformation temperature and strain rate to the mechanical properties of Aluminum (Al 99.0) were investigated by tensile experiment at different deformation temperatures and strain rate. At the end of investigation; it was determined that, with increasing deformation temperature, yield and tensile strenghts of the material decrease, strain rate and decrease of area increase, when plastic deformation exponent (n) decreases, strain rate accuracy exponent (m) increases. At a fixed temperature an increase in deformation speed increased all mechanical properties