Investigation of mechanical properties of Ramor600 steel joined by laser welding

Ramor armor steels, which come to the forefront in terms of their strength and hardness and ballistic properties, are the steels preferred worldwide for protection from armed attacks or explosions. Ramor armor steels; Different models such as Ramor 500, Ramor 550 and Ramor600, which are numbered over HBW hardness degrees. These armor steels are produced to absorb the impacts caused by the explosion pressure and high speed. Ramor 600, which is the subject of this thesis, is an extra-high hardness ballistic protection steel, which can be 3 and 6 mm thick and presented with a nominal hardness of 600 HBW. Explosion resistance, high hardness and ballistic values, Ramor armor steels; It creates a need in the defense industry, heavy industry, aviation, space and automotive industries. Laser welding was chosen as the welding method in armor steel. The main reason for this choice can be shown as the high heat density of the laser source and the small focusing diameter of the beam it creates. It is observed that the change in the internal structure of the weld zone is in a very narrow region. In addition, hard grain growth and metallurgical damage are minimized with this welding method, as the heat affected zone (ITAB) is large. In this study; By welding Ramor600 armor steel with laser welding method, the change in the welded region and the heat affected region (ITAB) due to welding and the mechanical properties of the welded region will be investigated as a result of tests such as microhardness, tensile, compression and notch tests. In addition, the test results were evaluated with the Taguchi optimization method in order to test the accuracy of the experiment, to determine the effect ratio of the parameters, and to save time and cost for future research. According to the results obtained, a variation analysis table of tensile strength and charpy impact strength was created. In these tables, the percent effect values of the active parameters are given.