Research of opportunities to improve welding technology for micro-alloyed steels

In the world, a lot of attention is devoted to improvement of welding technology for micro-alloyed steels. Bearing in mind that these steels, as a structural material, have a lot of use in various industries, there is a need for introduction of new welding processes and technologies. The subject of this project is improvement of the welding technology for micro-alloyed steels, in order to increase productivity and improve the quality of welded joints. It will be evaluated the following welding processes: a) SMAW, b) GMAW-MIG/MAG, c) FCAW-G with mixture of shielding medium (Ar, CO2 and O2) and d) FCAW-S. In the mixtures of shielding gases the content of Ar, CO2 and O2 would be different, because the preliminary investigations executed in Fac. of Mech. Eng. in Belgrade showed that the appropriate choice of the shielding gas mixture composition can affect the quality of the weld metal, and therefore the welded joint as a whole. Therefore, it is planned that the Project defines the mix of shielding gases and to compare the obtained quality of welded joints with the quality of joints made by SMAW process. Further, it was planned to made joints by FCAW-S process. FCAW-S process generally has not been applied in domestic industry, nor is our welders trained to work with this type of electrodes. It is also planned to investigate the influence of technologies on the properties of welded joints by different methods: mechanical testing, metallographic and fractographic examination.