Pojava hladnih pukotina pri zavarivanju visokočvrstog čelika S960 QL

The paper presents the study of weldability of micro-alloyed high-strength S960 QL steel with the application of experimental methods and mathematical models from the aspect of cold cracks occurrence. In the experimental part of the research RD (Research Department) test was applied to estimate the steels susceptibility to the occurrence of cold cracks. For the analysis of the impact of heat input on the mechanical properties of the welded joint the test steels were welded with one, two or more runs, out of which samples were made for the production of specimens in order to measure the hardness and impact strength in HAZ (heat affected zone). Based on the obtained results an estimate was provided regarding the weldability of S 960 QL steel as well as the proposal for further research.U ovom radu provedeno je istraživanje zavarljivosti mikrolegiranog čelika visoke čvrstoće S960 QL uz primjenu eksperimentalnih metoda i matematičkih modela s aspekta pojave hladnih pukotina. U eksperimentalnom dijelu istraživanja primjenjen je RD test za procjenu sklonosti čelika na pojavu hladnih pukotina. Za analizu utjecaja unosa topline na mehanička svojstva zavarenog spoja, zavarene su ispitne ploča s jednim, dva i više prolaza od kojih su načinjeni uzorci za izradu epruveta za mjerenje tvrdoća i udarne radnje loma u ZUT- u. Na osnovi rezultata dana je ocjena zavarljivosti čelika S 960 QL