Ceyhun Köse

Mechanical Properties of Laser Welded 2205 Duplex Stainless Steel

Abstract Duplex stainless steel is widely used in the oil, chemical industry and to a lesser extent in the medical industry, because of the high mechanical properties, corrosion resistance and good weldability. In this study, AISI 2205 (22Cr5Ni3Mo) duplex stainless steel samples were joined using the CO2 laser beam welding method. In order to determine the mechanical properties of the welded joints, tensile tests were applied and the hardness of the welded sample was measured on the cross-section. The microstructure characterization of welded samples was also carried out using optical microscopy, scanning electron microscopy and X-ray diffraction analysis. Although, the mechanical properties of welded samples were found acceptable, the final microstructure of the welded metal and the heat affected zone (HAZ) were significantly affected by the ferrite phase due to the low heat input that caused high cooling rates, respectively.

Weldability of 5754 aluminum alloy using a pulsed Nd:YAG micro scale laser

Abstract Use of laser welding is constantly increasing as it allows attainment of a high welding efficiency and weld quality. In this study, 5754 grade aluminum plates were joined on both sides by means of pulsed Nd:YAG power intensified micro scale laser welding method at three different laser powers in flat position by using supplemental welding wire. Mechanical properties of joints were examined by means of tensile and bending tests and by micro hardness measurements, and their structural changes were examined by means of optical microscope, SEM and EDS. As a result, it was determined that the welded joints could display an adequate tensile strength when exposed to tensile strain under action of static loads, but their bending strength remained relatively weaker. Mechanical properties of welded samples were observed to improve with increasing penetration depending on the increase in the laser power. It is believed that use of siliceous supplemental welding wire was also effective in strength improvement.

LAZER KAYNAĞI İLE BİRLEŞTİRİLEN AISI 2205 DUBLEKS PASLANMAZ ÇELİĞİN MEKANİK VE MİKROYAPI ÖZELLİKLERİNİN İNCELENMESİ

Bu calismada, AISI 2205 dubleks paslanmaz celik levhalar CO 2 lazer isini kaynak yontemiyle %50 Ar + %50 He gaz korumali ortamda, 4000W lazer gucuyle ve 90cm/dk kaynak hiziyla birlestirilmistir. Kaynakli birlestirmelerin mekanik ozelliklerini belirleyebilmek icin cekme ve centik darbe testleri uygulanmistir. Kaynakli baglantinin sertlik olcumu kaynak yonune dik kesitten gerceklestirilmistir. Mikroyapi karakteristikleri ise Optik mikroskop, Taramali Elektron Mikroskobu (SEM), Enerji Dagilimli X-Isini Spektroskopisi (EDS) ve XRD vasitasiyla incelenmistir. Sonuc olarak, CO 2 lazer kaynak yontemi ile birlestirilen dubleks paslanmaz celik kaynak metali ve isi tesiri altindaki bolgenin (ITAB) dusuk isi girdisine bagli yuksek soguma oranindan etkilenerek final yapisinin ferrit lehine degistigi tespit edilmistir. Kaynakli birlestirmenin mekanik ozellikleri kabul edilebilir degerlerde bulunmustur.

ROBOTİK MIG KAYNAK YÖNTEMİ İLE BİRLEŞTİRİLEN 5754 ALÜMİNYUM ALAŞIMININ MEKANİK VE MİKROYAPI ÖZELLİKLERİNE KAYNAK HIZININ ETKİSİ

MIG method has become the most preferred and the most wanted method in the welding of all the nonferro metals and alloys due to its convenience. In the welding operations with the usage of robotic MIG method that there are no defects which arise from welding operator has been the factor that increased the availability and reliability of this method. In a study done by starting from this point, AA 5754 aluminium sheets has been welded with robotic MIG method at different welding speed and their microstructure and mechanical properties has been analyzed. In this study optimum welding parameters and sufficient mechanical properties have been reached. Also it was shown that the changed welding speed affected the mechanical properties. These ideal parameters are believed to be important in their usage in industry

AISI 420 MARTENZİTİK PASLANMAZ ÇELİĞİN CO2 LAZER IŞINI KAYNAK YÖNTEMİYLE KAYNAK KABİLİYETİNİN ARAŞTIRILMASI

Bu calismada, temin edildigi ve isil islem uygulanmis sekliyle CO 2 lazer kaynak yontemiyle birlestirilen AISI 420 martenzitik paslanmaz celigin mekanik ve metalurjik ozellikleri arastirilmistir. Calisma sonucunda temin edildigi sekliyle birlestirilen numunelerin istenilen mekanik ozellikleri sergilemedigi belirlenmistir. Kaynak oncesi on tav ve kaynak sonrasi gerilme giderme isil islemi uygulanmis birlestirmelerin yapisindaki martenzitin temperlenmesi sonucu ozellikle ITAB ve kaynak metalinde mikrocatlak yayiniminin engellenmesi sonucunda istenilen mekanik ozellikler elde edilmistir.