Spiral wound fin tube: How does brazing technology ensure high bonding strength for long-term stability?

Spiral wound fin tube, as an indispensable high-efficiency heat transfer element in modern industry, is widely used in many fields such as power, HVAC, petrochemical industry, etc. Its core advantage lies in the unique spiral winding design, which greatly increases the heat dissipation area, thereby significantly improving the heat exchange efficiency. The bonding strength between the fin and the steel tube is one of the key factors affecting the long-term stability and reliability of spiral wound fin tubes.
In the manufacturing process of spiral wound fin tubes, brazing technology plays a vital role. Brazing is a welding method that relies on diffusion to form a strong joint by filling a brazing material with a low melting point between the welded parts and heating it to the brazing temperature so that the brazing material melts and wets the brazing surface. Although the bonding rate between the fin and the steel tube may be affected by many factors such as the brazing material composition, brazing temperature, and insulation time during the brazing process, a higher bonding strength can be achieved by optimizing these process parameters.
First of all, the selection of brazing material is crucial to the bonding strength. The composition of the brazing filler metal should have good fluidity and wettability to ensure that the gap between the fin and the steel tube can be fully filled during the brazing process and a uniform brazed joint can be formed. At the same time, the melting point of the brazing filler metal should match the material of the fin and the steel tube to avoid excessive thermal stress during the brazing process, which may cause cracking or deformation of the joint.
Secondly, the optimization of the brazing process parameters is also the key to improving the bonding strength. This includes selecting the appropriate brazing temperature, holding time, and cooling rate. The brazing temperature should be high enough to allow the brazing filler metal to fully melt and wet the brazing surface; but at the same time, it should also be avoided to be too high to avoid damage to the material of the fin and the steel tube. The holding time should be long enough to ensure that the brazing filler metal is fully diffused and forms a strong joint; but it should also be avoided to be too long to avoid overheating the joint and grain growth, thereby reducing the mechanical properties of the joint.
In addition, the gap adjustment between the fin and the steel tube is also an important factor affecting the bonding strength. Too large or too small a gap may result in the inability of the brazing filler metal to fully fill or form a poor brazed joint. Therefore, the gap between the fin and the steel tube needs to be strictly controlled during the manufacturing process to ensure the stability and reliability of the brazing quality.
By optimizing the brazing material composition and brazing process parameters, the spirally wound fin tube can achieve a higher bonding strength during the brazing process. This high bonding strength not only ensures the stability of the fin tube in long-term use, but also improves its corrosion resistance, fatigue resistance and other properties, thereby extending the service life of the equipment.