In this study, S235JR structural steel with/without primer in different thicknesses has been welded with submerged arc welding and effect of primer coating on the mechanical and microstructural properties has been investigated. During the study two different batch of test samples has been prepared, both are sand blasted to Sa 2 ½ and one of the batches has been covered with shop primer to 25 µm, 50 µm and 75 µm thicknesses. While carrying out analysis, surface texture and coating thickness has been designated as variables. It has been concluded that, 75 µm covered samples have yieded welding defections. Additionally, it has observed that coating thickness had a partial effect on mechanical properties of the material as highest hardness measurements has been observed at weld zones. Lastly, tensile, bending and impact tests has been performed, composite surface of failure has been analysed and only 75 µm covered sample plates has yielded non confirming results.

In this study, S235JR structural steel samples in uncoated condition and coated (shop-primer) in different thicknesses were welded by MAG (Metal Active Gas) welding method, and the effects of these applications on the mechanical and microstructure properties of the material were investigated. In the experimental studies, the first specimen group were used without any sandblasting and coating application, the second group specimens were sandblasted at Sa 2 ½ degree, and 25 µm, 50 µm, and 75 µm coatings were applied to the specimens in the other group. Surface conditions and coating thicknesses were selected as the variable parameters. With the examination of the radiography films, it was observed that the surface conditions affected the welded joint. As a result of the study, it was observed that altered coating thicknesses caused defects in the welding zone. It was determined that the coating thickness partially affected the mechanical properties, and the highest hardness values occurred in the weld zone in all samples. Relatively low values were obtained in tensile, bending and Charpy impact tests performed on sample groups with 75 µm coating thickness. The results were verified by the surface fracture, SEM, and EDS studies.

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ÖzKaynak, günümüzde en yaygın olarak kullanılan birleştirme yöntemlerinden biridir. Bu nedenle kaynak yapılacak parçaların güvenliği, kaynaklı birleştirmelerin kullanıldığı tüm yapının güvenilirliği için büyük önem taşımaktadır. Termal dönüşümler ITAB'ın geometrisi ve kaynak nüfuziyetindeki bilgileri sağlar. Bununla birlikte termal dönüşümlerin kontrolü kaliteli bir kaynağın kritiğidir. Bu çalışmada kaynak işlemi için kaynak yöntemi olarak yakma alın kaynağı seçilmiştir. Kaynak işlemi için uygun boyutlara getirilen numunelere belirli aralıklarla delikler açılarak kaynak işlemi esnasında termokupl ve datalogger yardımıyla kaynak işlemi boyunca sıcaklık değerleri ölçülerek kayıt altına alınmıştır. Aynı zamanda kaynak esnasında termal kamera kullanılarak kaynak bölgesinin ulaşabildiği maksimum sıcaklık ölçümü yapılmıştır. Kaynaklı birleştirilen deney parçalarının birleştirme bölgelerinde meydana gelen mikroyapısal değişiklikler, ışık mikroskobunda ve taramalı elektron mikroskobunda (SEM) incelenmiştir. Mekanik özelliklerin belirlenmesi adına mikro sertlik ölçümleri alınmıştır.