engleski

Characterization of Co-Cr alloys joints made by laser and TIG

U današnjoj protetskoj praksi spajanje dentalnih legura se sve češće provodi laserom i elektrolučno tj TIG-om. Svrha ovog rada bila je ocjena kvalitete spojeva Co-Cr legura zavarenih navedenim tehnologijama. Ispitivanja su provedena na odljevima 3 kobalt- kromove legure za skelete proteza: Wisil M (Austenal, Köln, Njemačka) ; I-MG (Interdent Celje, Slovenija) ; Brealloy F-400 (Bredent, Senden, Njemačka). Provedena su istraživanja makro- i mikrostrukture zavarenih spojeva, te su ispitana osnovna mehanička svojstva. Istraživanje je bilo usmjereno na ocjenu preklapanja točkastih zavara, pojavu i raspored toplih i hladnih pukotina, provarenost te na međusobni odnos izgleda lica zavara i odgovarajuće mikrostrukture u poprečnom presjeku. Dobiveni rezultati dokazuju povezanost postupaka i parametara spajanja s ispitivanim veličinama. Iako je spojeve izradio isti zubni tehničar s istim parametrima za laser, odnosno za TIG, razlike između uzoraka očituju se u obliku, dimenzijama i izgledu zavara, te provarenosti. Te razlike uzrokuju rasipanje vrijednosti izmjerenih mehaničkih svojstava spojeva a time posredno i smanjuju kvalitetu protetskog rada. Zaključno, uzimajući u obzir analizirane parametre, tehnologija zavarivanja laserom je pokazala makro- i mikroskopski kvalitetniji spoj od elektrolučnog zavarivanja.

Co-Cr alloys; Laser; TIG

In today’s dental practice different joining methods for dental materials have been used. Nowadays the most common way of joining dental alloys in prosthodontics are laser and tungsten inert gas welding (TIG). The purpose of this study was to evaluate the quality of joints of Co-Cr alloys made by these technologies. Tests were conducted on as-cast of three cobalt-chromium alloys for removable prosthodontic appliances: Wisil M (Austenal, Cologne, Germany) ; I-MG (Interdent Celje, Slovenia) ; Brealloy F-400 (Bredent, Senden, Germany). This research included analysis of macro-and microstructure of welded joints, and investigation of some basic mechanical properties. The focus was on the evaluation of overlapping weld beam, the shape and dimension of hot and cold cracks, penetration depths and the relation between the face of welds and its microstructure in cross- section. The results obtained in these reaserch showed correlation between joining methods and tested parameters. Although all joints were made by the same dental technician with the same parameters for laser and TIG equipment, the differences between the shape, size and appearance of the weld, and the penetration depths we