A method for fixing the attenuation ring in the inner cavity of a short millimeter wave coaxial magnetron

Abstract

The invention discloses a method for fixing an inner cavity of a short millimeter wave band coaxial magnetron and a damping ring. The method comprises the following steps: (A) spot welding of trace solder in advance: scissoring thin belts of gold-based brazing solder to perform indirect spot welding with an inner cavity pressure ring; (B) the inner cavity pressure ring after proper spot welding of the thin belts of the gold-based brazing solder is placed on the damping ring of the inner cavity of the short millimeter wave band coaxial magnetron under the condition of no stress; (C) secondary fusion welding of the trace solder: the local high-frequency heating of high-frequency heating equipment is used for fusing the thin belts of the gold-based brazing solder, and after the thin belts of the gold-based brazing solder are fused, the inner cavity pressure ring is firmly connected with an inner cavity wall. Through the adoption of the method, two-step welding of the thin belts of the gold-based brazing solder is used for fixedly connecting the inner cavity of the short millimeter wave band magnetron with the damping ring firmly, inner cavity blades and the inner cavity wall are not deformed easily, especially in high-temperature working environment, and as the gold-based series solder is used as continuous solder, evaporants are few, adverse effects on a negative pole are not easy to generate, the fixing reliability is high, and the stability of high-temperature work is good.

Description

technical field [0001] The invention belongs to the component welding technology of ultra-high frequency vacuum electronic devices, and in particular relates to a method for fixing an attenuation ring of a short millimeter wave band coaxial magnetron inner cavity. Background technique [0002] For the long-band coaxial magnetron, due to the large size of the inner cavity and the thickness of the inner cavity wall (above 0.8mm) is large enough, its hardness and mechanical strength are sufficient to ensure that the attenuation ring and the inner cavity of the magnetron will not be fixed. Cavity wall deformation. Therefore, there is no problem in the connection between the two by riveting or spot welding of oxygen-free copper strips. However, for the short millimeter wave band coaxial magnetron, because the cavity size of the short millimeter wave coaxial magnetron is small (diameter less than 5mm), and the inner cavity wall is also very thin (0.11-0.16mm), it is easy to cause...

AI Technical Summary

Problems solved by technology

If the direct welding fixation method is adopted, since the welding position is very close to the internal cavity gap, if the amount of solder is not well controlled, the molten solder will easily penetrate into the internal cavity gap during welding, resulting in unpredictable changes in the length of the gap. Unable to control welding quality

[0003] In addition, for the coaxial magnetron in the short millimeter wave band, since the electronic efficiency of the coaxial magnetron in the long millimeter wave band is generally 15-30%, the electronic efficiency of the coaxial magnetron in the long millimeter wave band is generally 15-30%. and lumen wall temperatures are much higher than the long millimeter band

When the electron efficiency of the long millimeter-wave band magnetron is 15-30%, the temperature of the blade and the inner cavity wall is lower than 120°C; while the temperature of the blade and the inner cavity wall of the short millimeter-wave band magnetron is 400°C even when the electron efficiency is 4%, When the efficiency is lower due to other factors, the temperature of the blade and the inner cavity wall may even reach 1000°C. Therefore, when the solder used for soldering is silver-based solder, the high-temperature evaporation of silver not only affects the reliability of the soldering place for long-term use, but also for The stable operation of the cathode has a strong hazard

Images