8. Development of Nozzle Blocks New Manufacturing Technology without Blazing

Annotation: The article describes the problems of manufacturing large-size nozzle blocks by classical for Ukrainian space industry method of high-temperature brazing. The Yuzhnoye SDO-selected way of solving this problem and the first strides on the way to organization of new production using innovative technologies of laser welding and surfacing are presented. The step-by-step sequence and procedure of research work to develop and test a new technology of cooled nozzle block manufacturing are described. Four phases are identified, out of which the first two phases have already been successfully performed. The laser welding and surfacing technology will allow avoiding the use of costly and unique equipment and will allow reducing and optimizing the technological manufacturing cycle rejecting the long –term and energy-consuming technological operations. The scientific-and-technological works performed showed the principle feasibility of making connection between the external jacket and internal wall of a nozzle block using laser welding. The test samples manufactured confirmed the high strength characteristics, which had been preliminary obtained by the theoretical calculation methods. The sections obtained by surfacing demonstrate good metallurgical connection between the layers. On the test samples, the technique was tried-out allowing repairing defect areas in a welded seam obtained by laser welding method. This is especially important from the technological and economic viewpoints, as the technology of high-temperature brazing applied currently does not allow making guaranteed repair of brazed joints.