Brazed spiral finned tubes are high-performance heat exchange elements that firmly connect fins to base tubes through advanced brazing technology. Their manufacturing process adheres to extremely strict technical specifications and precise process requirements to ensure reliability and durability in harsh industrial environments.

 

In terms of core processes and technical parameters, the brazing process is typically conducted in a vacuum or inert gas protective environment to prevent oxidation of the base material and brazing filler metal. In specific operations, the vacuum degree must be strictly controlled at a high level, such as in the range of 10⁻³ Pa to 10⁻⁵ Pa, which can effectively inhibit the formation of oxides and reduce defects such as pores and slag inclusions. Depending on the type of brazing filler metal selected, the process parameters vary: when using silver-based brazing filler metal, the furnace temperature needs to be accurately raised to 700–750 degrees Celsius and held for 20 to 30 minutes; if nickel-based brazing filler metal is used, the furnace temperature should be raised to 1000–1050 degrees Celsius and held for 40 to 60 minutes. During the post-welding cooling stage, the cooling rate must be controlled at 5–10 degrees Celsius per minute to avoid structural deformation caused by excessive temperature differences. Finished products must undergo non-destructive testing such as X-ray flaw detection to ensure no defects in welded joints and a tensile strength of over 40 megapascals.
 

 

 

In terms of performance characteristics and application scope, the brazing process endows finned tubes with excellent welded joint strength and outstanding high-temperature resistance. However, the production cycle of this process is relatively long, usually requiring 4 to 6 hours per batch, and the overall cost is relatively high due to the high price of brazing filler metal. Therefore, brazed spiral finned tubes are mainly suitable for special heat exchange requirements in high-end industrial fields such as high temperature and high pressure, such as high-efficiency heat exchangers in chemical, energy, and power industries.

 

Dimensional and quality requirements strictly follow industry standards. The fin height deviation shall not exceed ±0.5 mm, and the fin thickness deviation shall be controlled within ±0.1 mm. The average deviation of fin pitch within 10 pitches shall not be greater than 0.5 mm. The allowable straightness deviation of the finned tube is 0.1% of its length, with a maximum not exceeding 8 mm; the length deviation of a single finned tube is limited to ±2.0 mm. In terms of appearance, the fins shall be flat without warping, and the surface of the base tube shall be smooth without cracks, folds, or other defects.

 

It should be noted in the supplementary explanation that there are significant differences in process principles and application scenarios between brazed spiral finned tubes and high-frequency resistance welded spiral finned tubes. High-frequency resistance welding mainly achieves connection through resistance heating and is suitable for pressure vessels such as boilers; while brazing process relies on molten brazing filler metal for filling and focuses more on special working conditions such as high temperature and corrosion resistance. When selecting, a comprehensive judgment should be made based on actual operating conditions such as temperature, pressure, and corrosive environment to ensure optimal performance and safety.