High-frequency brazingRefers to heating the weld seam to the melting temperature of the alloy filler, while the metal being brazed has not yet reached its melting temperature. The low melting point alloy adheres the two metals together through strong surface tension, forming a solid weld after cooling.

With the development of technologies such as aerospace, rockets, missiles, radar, etc., microwave electronic traveling wave tubes, as key components of corresponding systems, are also continuously evolving. Due to stainless steel's excellent elasticity, thermal conductivity, and non-magnetic properties, high-frequency brazing has been widely applied in the microwave electronics field. Especially in high-frequency systems, microwave electronic traveling wave tubes use many complex-shaped, finely sized, and highly precise stainless steel parts. In fact, these stainless steel parts all need to be connected through high-frequency brazing methods. However, due to the poor brazing properties of stainless steel parts, the brazing must meet requirements for high strength, high vacuum tightness, and ease of mass production. Therefore, high-frequency brazing of stainless steel parts naturally becomes a key process in the manufacturing of traveling wave tubes. To meet brazing requirements, it is essential to first resolve which high-frequency brazing method to choose.

　　High-frequency brazingThere are various methods such as flux brazing, hydrogen-filled brazing, vacuum brazing, etc. Although these methods can achieve the connection of parts, analysis suggests that these methods are not suitable. This is because flux brazing can stick inside the device and is difficult to remove; absorbed hydrogen is hard for the gas-absorbing agent in the tube to absorb, leading to incomplete degassing issues; vacuum brazing requires heating both the welded object and its surroundings entirely. In cases where the size of the traveling wave tube itself is small, this large range of heating can directly damage assembled parts on the tube (such as ceramic-metal seals, slow-wave lines, collectors, concentrated attenuators, input-output components, etc.), causing deformation and ceramic cracking among other issues.

High-frequency brazing is achieved by generating heat flow through high-frequency current passing through metal to melt the filler material, filling the gaps of the welded parts and solidifying to form an inseparable connection. Since it involves localized heating of the welded parts with a fast heating speed, this method is particularly suitable for mass production of small-sized parts.