GÜÇ TRAFOLARI KAZAN İMALATINDA KULLANILAN SACLARIN MAG KAYNAK YÖNTEMİ İLE KAYNAKLANABİLİRLİĞİNİN ARAŞTIRILMASI
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Tarih
2023-04
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info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, güç trafoları kazan üretiminde genellikle tercih edilen S235 ve S355 yapı çelikleri MAG kaynak yöntemi kullanılarak, kendi aralarında ve birbirleri ile üç farklı kaynak akımı kullanılarak birleştirilmiştir. Birleştirmelerin kaynak bölgeleri tahribatsız ve tahribatlı muayene yöntemleri kullanılarak incelenmiştir. Kaynak bölgesinin tahribatsız olarak, yüzeysel ve yüzey altı/kaynak kesiti incelemeleri gözle (VT), sıvı penetrant (PT) ve manyetik parçacık (MT) testleri ile gerçekleştirilmiştir. Kaynaklı bölgesi mikroyapı ve mekanik özelliklerini de tahribatlı muayene yöntemlerinden optik mikroskop, mikrosertlik incelemeleri, çekme, eğme ve çentik darbe testleri ile incelenmiştir. Kaynaklı numunelere uygulanan tahribatsız testler sonucunda; gözle muayene, sıvı penetrant ve manyetik parçacık testlerinde kaynak yüzeylerinde standart toleransı dışında herhangi bir yüzeysel hata tespit edilmemiştir. Kaynaklı numunelere uygulanan tahribatlı testler sonrasında ise, kaynak bölgesinde tanelerin irileştiği ve tanelerin ergime çizgisinden kaynak merkezine doğru yönlendiği belirlenmiştir. Sertlik testleri sonucunda tüm kaynaklı birleştirmelerde en yüksek sertlik değeri kaynak metalinden ölçülürken onu sırasıyla ITAB’lar ve ana malzemelerin takip ettiği belirlenmiştir. Uygulanan çekme testleri sonucunda birleştirmelerin tümünde ana malzeme tarafında boyun vermiş ve yine ana malzeme tarafından sünek olarak kopma gerçekleşmiştir. Kaynaklı numunelerin kaynak bölgesinde ise herhangi bir hasar gözlenmemiştir. Eğme testleri sonucunda bütün birleştirmelerde kaynak bölgesinde göz ile görülebilir herhangi bir hataya rastlanılmamıştır. Çentik darbe testleri sonucunda en yüksek darbe tokluğunu S235-S235 kaynaklı numune (1 nolu kaynak akımı) ITAB’ından elde edilirken, en düşük darbe tokluğu S355-S355 kaynaklı numune (3 nolu kaynak akımı) kaynak metalinden elde edilmiştir.
In this study, S235 and S355 structural steels, which are generally preferred in power transformer boiler production, were combined using MAG welding method, using three different welding currents among themselves and with each other. The weld zones of the joints were examined using non-destructive and destructive testing methods. Non-destructive, superficial, and sub-surface/weld section examinations of the weld area were performed by visual (VT), liquid penetrant (PT) and magnetic particle (MT) tests. The macro/microstructure and mechanical properties of the welded area were also investigated by using destructive testing methods such as optical microscopy, microhardness examinations, tensile, bending and notch impact tests. As a result of non-destructive tests applied to welded samples; In visual inspection, liquid penetrant and magnetic particle tests, no superficial defects were detected on the weld surfaces other than the standard tolerance. After the destructive tests applied to the welded samples, it was determined that the grains got coarser in the weld area, the grains were oriented towards the weld center from the melting line. As a result of the hardness tests, it was determined that the highest hardness value was measured from the weld metal in all welded joints, followed by HAZ’s and base materials, respectively. As a result of the applied tensile tests, all of the joints gave neck on the base material side and ductile rupture occurred on the base material. No damage was observed in the weld area of the welded samples. As a result of the bending tests, no visible defects were found in the weld area in all joints. As a result of the notch impact tests, the highest impact toughness was obtained from the S235-S235 welded sample (welding current no. 1), while the lowest impact toughness was obtained from the S355-S355 welded sample (welding current no. 3)."
In this study, S235 and S355 structural steels, which are generally preferred in power transformer boiler production, were combined using MAG welding method, using three different welding currents among themselves and with each other. The weld zones of the joints were examined using non-destructive and destructive testing methods. Non-destructive, superficial, and sub-surface/weld section examinations of the weld area were performed by visual (VT), liquid penetrant (PT) and magnetic particle (MT) tests. The macro/microstructure and mechanical properties of the welded area were also investigated by using destructive testing methods such as optical microscopy, microhardness examinations, tensile, bending and notch impact tests. As a result of non-destructive tests applied to welded samples; In visual inspection, liquid penetrant and magnetic particle tests, no superficial defects were detected on the weld surfaces other than the standard tolerance. After the destructive tests applied to the welded samples, it was determined that the grains got coarser in the weld area, the grains were oriented towards the weld center from the melting line. As a result of the hardness tests, it was determined that the highest hardness value was measured from the weld metal in all welded joints, followed by HAZ’s and base materials, respectively. As a result of the applied tensile tests, all of the joints gave neck on the base material side and ductile rupture occurred on the base material. No damage was observed in the weld area of the welded samples. As a result of the bending tests, no visible defects were found in the weld area in all joints. As a result of the notch impact tests, the highest impact toughness was obtained from the S235-S235 welded sample (welding current no. 1), while the lowest impact toughness was obtained from the S355-S355 welded sample (welding current no. 3)."
Açıklama
Anahtar Kelimeler
MAG kaynağı, Yapı çeliği, Tahribatsız test, Tahribatlı test., MAG welding, structural steel, non- destructive testing, destructive testing.
