DEVELOPMENT AND TESTING OF AUXILIARY TECHNOLOGICAL EQUIPMENT FOR LASER WELDING OF THIN-WALLED T-JOINTS IN VARIOUS SPATIAL POSITIONS

Abstract

This study examines ways to improve the efficiency of laser welding of T-joints by developing specialized welding equipment. It is shown that, despite a significant body of research on the properties of welded joints, the issue of ensuring welding process stability through equipment design remains understudied. The aim of this work is to create and experimentally test technological equipment for laser welding of T-lap joints in various spatial positions. The developed equipment includes a clamp for fixing samples and a laboratory stand with a two-axis laser head movement system. The clamp design ensures precise alignment of the joint elements, adjustable fixing of the edge, and uniform supply of shielding gas from both sides of the edge. The laboratory stand enables controlled movement along the X and Z axes using servo drives and ball-screw drives, which allows for high positioning accuracy and process reproducibility. The ability to change the spatial position of the weld by tilting the work frame is provided. Experimental studies were conducted on the welding of T-joints made of  austenitic and austenitic-ferritic stainless steels using an Nd:YAG laser with a power of up to 4.4 kW. Microstructural analysis revealed the formation of a fine-grained austenitic weld structure with a negligible content of δ-ferrite and a narrow heat-affected zone. It was established that the weld geometry is stable, and the structural characteristics are uniform throughout the welded joint. The results of mechanical tests confirmed the high strength of the welded joints. The results obtained demonstrate the effectiveness of the developed process equipment and the possibility of its use for forming high-quality T-joint welds in various spatial positions that meet the requirements of DSTU EN ISO 13919-1:2019 and are characterized by the highest quality level «B».