Patent RU-2722211-C1 (RU)
Title: Spiral manufacturing method for twt retardation system
Inventor: SHALAEV PAVEL DANILOVICH
IPC: H01J23/24
Filed: 2019-07-05
Granted: 2020-05-28
Abstract: FIELD: electronic equipment.SUBSTANCE: invention relates to the field of electronic equipment, namely to spiral slow-wave systems of traveling-wave tubes (TWT). Making the slow-wave systems for the TWT retardation system comprises the steps of winding the metal band onto the rotating inner mandrel, degreasing, cleaning, moulding annealing and spiral release from the internal mandrel, at that, the spiral is wound from two tapes - tapes from refractory metal, for example, tungsten or molybdenum, and metal bands with high plasticity and electrical conductivity, for example, copper or composite material based on copper. When performing the winding of these tapes on the rotating internal mandrel, these tapes are wound on the internal mandrel simultaneously, wherein refractory metal tape is wound directly on inner mandrel, and tape from metal with high plasticity and electric conductivity is wound on internal mandrel over tape from refractory metal, providing in spiral tight attachment of this tape to tape from refractory metal. After winding ends of spiral are fixed on inner mandrel, unused parts of metal bands are cut off, from which spiral is wound, and degreasing is performed and spiral is cleaned on inner mandrel. Then, without removing from the inner mandrel, the defatted and cleaned spiral is placed in the other, external to the spiral, mandrel from material with a lower coefficient of thermal expansion than the metal with high plasticity and electrical conductivity, from which the external spiral tape is made; fixing the spiral with internal mandrel in external mandrel with provision of tight fit of internal surface of external mandrel enveloping spiral, to external surface of spiral. Then forming spiral annealing is performed, thermal reduction of part of spiral from metal band with high plasticity and electric conductivity and diffusion welding of helically wound ribbons from tape with metal band with high plasticity and electroconductivity at low pressure - no more than 10mm of mercury (1.33⋅10Pa), forming temperature of part of spiral from refractory metal and thermal reduction of part of spiral from tape from metal with high plasticity and electrical conductivity 880–930 °C for 15–20 minutes and temperature of diffusion welding 550–600 °C for 30–40 minutes. During moulding of spiral annealing at temperature of 880–930 °C, due to difference in coefficients of thermal expansion of material of outer mandrel and metal with high ductility and electrical conductivity, thermal reduction of part of spiral from metal band with high ductility and electric conductivity. When temperature is reduced to 550–600 °C, tapes wound in a spiral are squeezed due to difference in coefficients of thermal expansion of refractory metal and metal with high ductility and electrical conductivity. At that, all necessary conditions for diffusion welding are provided. Under the conditions obtained under low pressure, compression of welded metals and temperature during 30–40 minutes, diffusion welding of ribbons from refractory metal and metal with high plasticity and electroconductivity along their common boundary is performed. After moulding of spiral annealing and diffusion welding of tapes wound on inner mandrel, spiral is released from mandrels at normal temperature and atmospheric pressure and spiral is re-cleaned.EFFECT: manufacturing of spiral for TWT retarding system, reduction of spiral temperature, reduction of losses of UHF power in slow-wave systems, increased service life of TWT, increased contour and general efficiency of TWT.4 cl, 3 dwg