Elektrospark yöntemiyle TiC-Co ve CrNi kaplanmış elektrotların yüksek mukavemetli çeliklerin nokta direnç kaynağına etkisi
Küçük Resim Yok
Tarih
2018
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Karabük Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Nokta direnç kaynak elektrot uç yüzeyi kaplamanın, elektrot kalitesine ve ömrüne etkileri daha önce farklı araştırmacılar tarafından incelenmiştir. Ancak, bu alanda kullanılan kaplamalı elektrotların çelik sacların nokta direnç kaynak kalitesi üzerindeki etkileri literatür araştırmalarında yer almamaktadır. Bu amaçla çalışmada, kaplamalı elektrotlarla nokta direnç kaynak yöntemiyle birleştirilen ileri seviye yüksek mukavemetli DP600 ve TRIP800 çeliklerin kaynak kalitesi incelenmiştir. Birleştirme işleminde kullanılan Cu-Cr-Zr elektrotların uç yüzeylerine elektrospark kaplama (ESD) yöntemi ile farklı voltajlar (40V-80V-120V) altında TiC-Co ve CrNi kaplama işlemleri yapılmıştır. DP600 ve TRIP800 çelik sac çiftleri Cu-Cr-Zr, TiC-Co kaplamalı ve CrNi kaplamalı elektrotlarla birleştirilmiştir. Birleştirmelere çekme makaslama testleri ve çapraz çekme testleri uygulanarak, statik yük altındaki davranışları incelenmiştir. Stereo mikroskop aracılığıyla kaynak çekirdek geometrisi incelenerek çekirdek boyutları ölçülmüş ve elektrot dalma derinliği tespit edilmiştir. Ayrıca kaynaklı birleştirmelerin sertlik ölçümü yapılmıştır. Metalografik incelemeler optik mikroskop, SEM, XRD ve EDS analizi vasıtasıyla incelenmiştir. İlave olarak çalışmada elektrot ömrünü belirlemek amacıyla 0 ile 100 kaynak arasında belirli aralıklarla elektrot ağırlığı ölçülerek ağırlık kayıpları hesaplanmıştır. Kullanılan elektrotların makro uç fotoğrafları alınarak mantarlaşma boyutu hesaplanmıştır. Elde edilen bulgulara göre, TiC-Co ve CrNi ile ESD yöntemiyle kaplanarak nokta direnç kaynak elektrotların aşınma direnci ve ömrü iyileştirilebilir. Ayrıca, elektrot uç yüzeyindeki kaplamanın birleştirmenin özelliklerine etki ederek kaynak kalitesi üzerinde etkisi olduğu bulunmuştur.
The effects of resistance spot welding electrode tip surface coating on electrode quality and lifetime have been previously studied by different researchers. However, the effect of the electrode tip coating on the resistance spot weld quality of the steel sheets is not included in the literature search. For this purpose; the weld qualities of advanced high strength DP600 and TRIP800 steels, which have been joined with resistance spot welding by coated electrodes, have been investigated. TiC-Co and CrNi coatings were performed with various voltage settings (40V-80V-120V) by electrospark coating (ESD) method on the end surfaces of Cu-Cr-Zr electrodes used in the joining process. DP600 and TRIP800 steel sheet couples have been joined with uncoated Cu-Cr-Zr, TiC-Co coated and CrNi coated electrodes. Behaviors of joined samples under static load were investigated by applying tensile shear tests and cross tension tests. Examining the weld nugget geometry through a stereo microscope; the nugget size were measured and the electrode indentation depth was determined. Metallographic investigations were examined by optical microscope, SEM, XRD and EDS analysis. In addition, in order to determine the electrode life, weight loss was calculated by measuring the electrode weight at certain intervals between 0 and 100 welding process. The mushrooming size was calculated by taking the macro end photographs of the used electrodes. According to findings, the coating with TiC-Co and CrNi by ESD method can improve the wear resistance and life of point resistance welding electrodes. Furthermore, it has been found that the coating on the electrode end surface has an effect on the weld quality by influencing the properties of the joining.
The effects of resistance spot welding electrode tip surface coating on electrode quality and lifetime have been previously studied by different researchers. However, the effect of the electrode tip coating on the resistance spot weld quality of the steel sheets is not included in the literature search. For this purpose; the weld qualities of advanced high strength DP600 and TRIP800 steels, which have been joined with resistance spot welding by coated electrodes, have been investigated. TiC-Co and CrNi coatings were performed with various voltage settings (40V-80V-120V) by electrospark coating (ESD) method on the end surfaces of Cu-Cr-Zr electrodes used in the joining process. DP600 and TRIP800 steel sheet couples have been joined with uncoated Cu-Cr-Zr, TiC-Co coated and CrNi coated electrodes. Behaviors of joined samples under static load were investigated by applying tensile shear tests and cross tension tests. Examining the weld nugget geometry through a stereo microscope; the nugget size were measured and the electrode indentation depth was determined. Metallographic investigations were examined by optical microscope, SEM, XRD and EDS analysis. In addition, in order to determine the electrode life, weight loss was calculated by measuring the electrode weight at certain intervals between 0 and 100 welding process. The mushrooming size was calculated by taking the macro end photographs of the used electrodes. According to findings, the coating with TiC-Co and CrNi by ESD method can improve the wear resistance and life of point resistance welding electrodes. Furthermore, it has been found that the coating on the electrode end surface has an effect on the weld quality by influencing the properties of the joining.
Açıklama
Fen Bilimleri Enstitüsü, İmalat Mühendisliği Ana Bilim Dalı
Anahtar Kelimeler
Metalurji Mühendisliği, Metallurgical Engineering
