METALLOGRAPHIC EXAMINATIONS OF WELDED JOINTS

Tema ovog rada je metalografska ispitivanja zavarenih spojeva. Rad se sastoji od teorijskog i eksperimentalnog dijela. U teorijskom dijelu objašnjen je zavareni spoj i njegove komponente te utjecaj temperature na strukturu i svojstva zavarenog spoja. Od velike važnosti je pravilna izvedba zavarenog spoja kako ne bi došlo do pojave grešaka u zavaru. Dane su najčešće greške koje mogu nastati te njihov utjecaj na strukturu je objašnjen tekstom i slikama. Dalje u radu su objašnjena metalografska ispitivanja te su opisani ciljevi i postupak ispitivanja prema normi ISO 17639. U eksperimentalnom dijelu su provedena metalografska isptivanja zavarenog spoja, u okviru kojih je ispitana makro i mikrostruktura. Ispitivanja su se provodila na materijalu St 52-3. Objašnjen je postupak pripreme uzorka prije postupka metalografskih ispitivanja. Nakon svih ispitivanja analizirani su rezultati te njihovom analizom može se zaključiti da je zavar, iako ima malih pojava oksida na presjeku, dobro napravljen.The topic of this paper is metallographic testing of welded joints. The work consists of a theoretical and experimental part. The theoretical part explains the welded joint and its components as well as the influence of temperature on the structure and properties of the welded joint. It is of great importance that the welded joint is properly carried out so that no errors occur. The most common mistakes are given which can arise and their impact on the structure is explained by text and images. Further in the paper, the metalographic tests, the objectives and test procedure are described in accordance with ISO 17639. In the experimental part, metallographic tests of the welded joint were performed, within which macro and microstructure was examined. The tests were conducted on material St 52-3. The procedure for preparing the test sample before the metallographic testing procedure is explained. After all the tests, the results were analyzed, and by their analysis it can be concluded that the welded joint, although having small occurrence of oxide, is well made