S355J2 çeliğinin ısıl işlem ve farklı tozaltı kaynak tellerinin kaynak kabiliyetine etkisinin incelenmesi
Küçük Resim Yok
Tarih
2012
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Karabük Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada; %0.14 C, %1,54 Mn, %0,36 Si, %0,02 P, ve %0,022 S kimyasal içeriğe sahip ve 389 N/mm2 akma mukavemetine, 597 N/mm2 çekme mukavemetine sahip S355J2 kalite çelik kullanılmıştır. Tez çalışmasında kullanılan parçaların yarısı 780 °C sıcaklıkta ısıl işlem uygulanmış ve suda soğutularak çift-fazlı yapı elde edilmiştir. Isıl işlem sonrasında elde edilen 780 S malzemeler ve ısıl işlem görmemiş S355J2 genel yapı çeliği S1 ve S2Mo tozaltı kaynak telleri ile atölye ortamında kaynatılmış ve kaynaklı numunelerden standartlara uygun parçalar kesilmiş, tahribatlı ve tahribatsız muayeneleri gerçekleştirilmiştir. Tahribatlı muayenelerde; numunelerin çekme, darbe çentik, eğme testleri ve sertlik testleri gerçekleştirilmiştir. Tahribatsız muayenelerde; numunelerin gözle kontrol, ultrasonik muayene, manyetik parçacık muayene, mikroyapı, makroyapı ve SEM analizleri gerçekleştirilmiştir. Numunelerin gözle kontrol, ultrasonik ve manyetik parçacık muayene kontrollerinde herhangi kaynak hatasına rastlanmamıştır. Çekme testlerinde ise kaynaklı numunelerin hepsi ısı tesiri altında kalan bölgeden (ITAB) kopmuştur. Eğme testlerinde numuneler uygun çapta mandrellerle 180 derece eğilmiş ve herhangi çatlama görülmemiştir. Çentik darbe testlerinde ise S2Mo kaynak teli kaynatılan numunelerin tokluk değerlerinin belirgin bir şekilde yüksek olduğu görülmüştür. Çentik darbe testi ve çekme testlerinin kopma yüzeylerine SEM incelemesi, ayrıca kaynak bölgelerinin mikroyapı, makroyapı ve SEM incelemeleri yapılarak iç yapı analizi gerçekleştirilmiştir.
In this study, S355J2 steel with a chemical composition of 0.14 % C, 1.54 % Mn, 0.36 % Si, 0.02 % P, 0.022 % S and mechanical properties of 389 N/mm2 yield strength and 597 N/mm² tensile strength were used. Half of the specimens in this study were obtained at 780 °C heat treatment temperature and water-cooled dual phase steel. S355J2 and 780 S steels were welded with S1 and S2Mo submerged arc welding wires. Test pieces were taken from the welded specimens for destructive and non-destructive tests according to related standards and performed mentioned tests. As destructive tests; tensile, notch toughness, bending tests and hardness tests were performed. As non-destructive tests; visual inspection, ultrasonic testing, magnetic particle testing, microstructure, macrostructure and SEM analysis were performed. There were no welding defects after visual inspection of the samples, ultrasonic and magnetic particle testing methods. As a result of tensile tests, all of the welded tensile test pieces ruptured from heat affected zone. After bending tests, there were no cracks on the welded test specimens. Impact toughness tests showed that pieces welded with S2Mo submerged arc welding wire were higher impact toughness value than those welded with S1 submerged arc welding wire. From fracture surface of impact toughness test and tensile test specimen were observed by SEM examination. Also welding zone, HAZ and base material zone of welded specimens were microstructure and macrostructure analyzed and observed by SEM examination.
In this study, S355J2 steel with a chemical composition of 0.14 % C, 1.54 % Mn, 0.36 % Si, 0.02 % P, 0.022 % S and mechanical properties of 389 N/mm2 yield strength and 597 N/mm² tensile strength were used. Half of the specimens in this study were obtained at 780 °C heat treatment temperature and water-cooled dual phase steel. S355J2 and 780 S steels were welded with S1 and S2Mo submerged arc welding wires. Test pieces were taken from the welded specimens for destructive and non-destructive tests according to related standards and performed mentioned tests. As destructive tests; tensile, notch toughness, bending tests and hardness tests were performed. As non-destructive tests; visual inspection, ultrasonic testing, magnetic particle testing, microstructure, macrostructure and SEM analysis were performed. There were no welding defects after visual inspection of the samples, ultrasonic and magnetic particle testing methods. As a result of tensile tests, all of the welded tensile test pieces ruptured from heat affected zone. After bending tests, there were no cracks on the welded test specimens. Impact toughness tests showed that pieces welded with S2Mo submerged arc welding wire were higher impact toughness value than those welded with S1 submerged arc welding wire. From fracture surface of impact toughness test and tensile test specimen were observed by SEM examination. Also welding zone, HAZ and base material zone of welded specimens were microstructure and macrostructure analyzed and observed by SEM examination.
Açıklama
Fen Bilimleri Enstitüsü, Metalurji ve Malzeme Mühendisliği Ana Bilim Dalı
Anahtar Kelimeler
Metalurji Mühendisliği, Metallurgical Engineering