Kolisnyk R. Metal and composite embedded heating elements for welding of thermoplastic polymers

The research is devoted to the development of embedded heating elements (EHE) and welding parameters to improve the bonding between the heating element and the surfaces of polymeric materials with the ultimate goal of increasing the mechanical strength of the welded joints. In the work to solve the scientific and technological task was carried out modification of the surface of typical embedded heating elements of stainless steel and titanium by microplasma spraying such materials as nichrome, titanium, molybdenum, and steel 65G and developed innovative embedded heating elements based on electrically conductive polymer composites that provide formation of butt and overlap joints with a strength level of, respectively, 95 ... 98% and 100% strength of the base material. Welding with an embedded welding element (WEHE) is primarily used for joining parts of complex configurations in the aerospace, automotive, and shipbuilding industries. In this case, the embedded heating element remains in the welded joint. Due to the fact that its structure and properties differ from the basic material of parts, the adhesion between them is low, and the operation under conditions of cyclic temperature-force conditions may lead to failure of the welded joints. Therefore, the relevance of increasing the strength of welded joints by improving the adhesion between embedded heating element and polymeric material of parts in the welded joint is still relevant. At the same time, another way of solving the mentioned problem could be the use of embedded heating element, which is as close as possible to the basic polymeric material of the parts by their properties. In this regard, it is relevant to create and investigate electrically conductive polymeric composites based on the polymer from which the parts to be welded are made and to use them as embedded heating elements for welding.