Production of blanks for flexible waveguide sections of the spacecraft by laser welding

Currently, JSC “ISS” named after Academician M. F. Reshetnev is working on the development of the production of billets of flexible waveguide sections (DHW) with sections from 20 ´ 10 to 70 ´ 30, with a wall thickness of 0.1 mm made of BrB2 copper alloy. The maximum deviation of the size of the inner channel is not more than 0.1 mm. Such methods of manufacturing DHW blanks by pressure, such as rolling and drawing, take up to 20 working shifts and include a large number of cycles (from 6 to 8), require heat treatment and etching of parts after each cycle. In this regard, the task was set to reduce the complexity of the production of DHW blanks. The solution to the problem can be welding of shells from sheet blanks on a forming device, followed by the execution of a longitudinal seam. As part of the solution of the task, the calculation of the amount of energy required to melt the edges of the part was carried out, the analysis of the possibility of assembly by various welding methods for welding thin-walled shells with exact dimensions was carried out. The analysis of the material showed that welding should be carried out in inert media. The following methods were chosen for welding the samples: arc welding in the environment of argon protective gas with a non-melting electrode, microplasma and laser welding. In the course of the work, 30 samples of 100 ´ 200 were welded, showing that 70 % of the samples are defective during arc welding and microplasma welding, while only 5 % are formed during laser welding. The following conclusions are obtained: with arc welding methods of small thicknesses, unacceptable defects occur due to the instability of the arc, whereas when using laser welding, uniform formation of the weld is observed. Metallographic studies and tensile tests were carried out on samples welded by laser welding, showing the specific strength of the weld metal at least 90 % of the strength of the base metal and the absence of defects in the cross section of the weld metal.