Thermal joining of steel/polymer/steel composite materials using non-direct arcprocess technique

The objective of the conducted investigation is to develop a joining technology for similarly thermal joining of steel/polymer/steel composite materials, as well as dissimilarly thermal joining to DC + ZE - steel. The composite material consists of galvanized steel sheets that covering a core of polymer layer. Filler materials that used in this investigation are Sn99.9 and SnCu3. Two arc-welding processes under aiding of robotic torch-controlled system were used. The first is plasma non-contact arc process. With this process, similar joining of the steel/polymer/steel composite materials was performed. However, delamination could not be avoided. Other process is cold-wire TIG welding process. With this process, the heat input is controlled using specific torch design and by evaluation of joining parameters, which leads to minimizing delamination and to enhance wetting of filler metal on the base material surfaces. The joint strength reach up to 65-70 % of the tensile strength of the base composite material.