Yüksek mukavemetli çeliklerde çok pasolu kaynağının mekanik ve mikroyapı özelliklerine etkisi
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Date
2018
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Düzce Üniversitesi
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info:eu-repo/semantics/openAccess
Abstract
S460M kalite yüksek mukavemetli çelik; sağladığı avantajlardan dolayı taşımacılık sektöründeki ağır vasıtalarda ve çelik yapı sektöründe önem kazanmaya başlamıştır. Bu malzemelerin Osman Gazi körfez geçiş köprüsü ve III. Boğaz Köprüsü olan Yavuz Sultan Selim Köprüsü`nün yapımında da tercih edilmesi nedeniyle yakın gelecekte yapılacak olan Çanakkale Köprüsü ve buna benzer irili ufaklı birçok prestijli projelerde kullanılacağın sinyalini vermektedir. Bu veriler ışığında otomotiv sanayi ve yapı sektörüne aynı anda hitap edebilecek şekilde 8 mm ve 20 mm kalınlığındaki yüksek mukavemetli çeliklerin hem çok pasolu uygulamaların mekanik ve mikro yapı özelliklerine etkilerinin kıyaslanabilmesi, hem de çok pasolu uygulamaların farklı malzeme kalınlıklarına etkisinin tespit edilmesi hedeflenmiştir. Bu çalışmada, S460M çeliği GMAW/FCAW yöntemi ile robot kullanılarak, düz çoklu paso kaynağı veya salınımlı çoklu paso kaynağı yöntemleri uygulanarak birleştirilmiştir. Birleştirilen parçalardan çıkarılan numunelere tahribatlı ve tahribatsız testler uygulanarak elde edilen sonuçlar kayıt altına alınmıştır. Test numunelerinin mekanik özelliklerini tespit etmek için çentik darbe deneyinden, çekme deneyinden, mikro sertlik ölçme yönteminden, makro inceleme yönteminden, mikro yapı inceleme ve SEM yöntemlerinden yararlanılmıştır ve elde edilen veriler birbiriyle kıyaslanabilmiştir. Yapılan çalışmalar neticesinde salınımlı çoklu paso uygulamasıyla torca salınım hareketi vererek kaynak yapmanın, kaynaklı imalat süresinde ve mekanik değerlerde avantajlar sağladığı görülmüştür. Numunelerin mikro yapı incelemesinde; ferrit ağırlıklı, düşük miktarlarda perlit içeren ince taneli yapı gözlemlenmiştir. Kırık yüzeylerin SEM ile incelemesinde ana malzemeye yakın bölgede sünek, ısı tesiri altındaki bölgede, ana malzemeye kıyasla daha rijit kırılmanın gerçekleştiği gözlemlenmiştir.
S460M quality high strength steel has begun to gain importance in the steel sector and the heavy vehicles in the transportation sector. Due to being preferred of these materials in the construction of Yavuz Sultan Selim Bridge, the 3rd Bridge on Bosphorus, and Osmangazi Bridge, on Izmit Gulf, this gives us a clue that high strength steels will be used in construction of Canakkale Bridge which is soon and many other more or less important prestigious building projects in the near future. In the light of these data the way that appealing to automotive industry and building trade simultaneously, it is aimed to be able to compare effects of high strength steels multipass applications which are 8 mm and 20 mm thick on features of mechanical and micro structures; to determine effects of multipass applications on varied material thickness and to cut down on manufacturing costs by accelerating preparation process of PQR and WPS. In this study, the S460M steel was combined using the GMAW / FCAW method using a robot, flat multi-pass welding or oscillating multi-pass welding methods. The results obtained by applying destructive and non-destructive tests to recorded samples are recorded. In order to determine the mechanical properties of the test samples, the notch impact test, the tensile test, the micro hardness test, the macro inspection method, the micro structure inspection and the SEM methods were utilized and the obtained data were compared with each other. As a result of the work done, it is seen that welding by torch oscillation movement with oscillating multi-pass application gives advantage in welded manufacturing process and mechanical values. In the microstructure examination of the samples; fine grained structure containing perlite was observed in low amounts. The fractured surfaces were observed by SEM to have a more rigid fracture in the ductile, heat-affected zone near the main material than in the main material.
S460M quality high strength steel has begun to gain importance in the steel sector and the heavy vehicles in the transportation sector. Due to being preferred of these materials in the construction of Yavuz Sultan Selim Bridge, the 3rd Bridge on Bosphorus, and Osmangazi Bridge, on Izmit Gulf, this gives us a clue that high strength steels will be used in construction of Canakkale Bridge which is soon and many other more or less important prestigious building projects in the near future. In the light of these data the way that appealing to automotive industry and building trade simultaneously, it is aimed to be able to compare effects of high strength steels multipass applications which are 8 mm and 20 mm thick on features of mechanical and micro structures; to determine effects of multipass applications on varied material thickness and to cut down on manufacturing costs by accelerating preparation process of PQR and WPS. In this study, the S460M steel was combined using the GMAW / FCAW method using a robot, flat multi-pass welding or oscillating multi-pass welding methods. The results obtained by applying destructive and non-destructive tests to recorded samples are recorded. In order to determine the mechanical properties of the test samples, the notch impact test, the tensile test, the micro hardness test, the macro inspection method, the micro structure inspection and the SEM methods were utilized and the obtained data were compared with each other. As a result of the work done, it is seen that welding by torch oscillation movement with oscillating multi-pass application gives advantage in welded manufacturing process and mechanical values. In the microstructure examination of the samples; fine grained structure containing perlite was observed in low amounts. The fractured surfaces were observed by SEM to have a more rigid fracture in the ductile, heat-affected zone near the main material than in the main material.
Description
YÖK Tez No: 509532
Keywords
Metalurji Mühendisliği, Metallurgical Engineering, Gazaltı kaynağı, Gas metal arc welding, Kaynak, Welding, Kaynak dikişleri, Welding seams, Kaynak metali, Weld metal, Kaynak parametreleri, Welding parameters, Kaynak teli, Welding wire, Kaynaklı yapılar, Welded structures
