Aspects Regarding Welding of DD13 Steel by Applying the FSW Process and some Processes Derived from it

Due to its characteristics, DD13 steel is recommended for various applications in the automotive field (including in the manufacture of components for car bodies). The paper presents solutions proposed by ISIM Timisoara for welding of DD13 steel, as alternative solutions to conventional welding processes. One solution that has proven to be viable for joining DD13 steel is the friction stir welding process (FSW). In terms of the quality of the welded joints obtained by applying the classic FSW welding process, these welds were excellent. In an attempt to obtain other benefits, mainly related to the efficiency of the welding process, ISIM Timisoara has developed research programs for the study and application of other methods based on the FSW process principle, namely: - hybrid friction stir welding ultrasonic assisted FSW-US; - friction stir welding in inert gas environment FSW – IG. The important effects due to the application of these methods are: improving (as appropriate) the degree of plasticization of the materials to be joined and increasing the degree of mixing of the materials as result of ultrasonic assistance of the FSW welding process; improvement of the welding process by reducing the pressing forces of the tool during welding, with an effect on increasing the service life of welding tool; respectively improving the aspect of the weld and some mechanical characteristics of the welded joints (at tensile tests, respectively static bending test). The obtained results showed that the two methods derived from the classical FSW welding process, can be used in industrial applications, with important benefits.