High frequency welded finned tubes are used to heat the steel strip and the outer surface of the steel tube until the plastic state or melting by using the skin effect and proximity effect of the high-frequency current while the steel strip is wound around the steel tube, and the welding is completed under a certain pressure when the steel strip is wound. This kind of high-frequency welding is actually a solid phase welding. Compared with inlaying, brazing (or overall hot galvanizing) and other methods, it is good in terms of product quality (high welding rate of fins, up to 95%), productivity and automation. High frequency current is adopted, and winding is carried out at the same time
The tube and fin are basically integrated, and the welding rate is an important index to judge the quality of the fin tube.
High frequency welded finned tubes are suitable for high temperature and high pressure applications. The base tube is made of stainless steel or ND steel for corrosion protection. When the cooling temperature is above the dew point, it is clear that there is no working environment where condensate is generated. Ordinary carbon steel can also be used as the base tube.
The thickness of high-frequency welded fin tube is usually more than 0.8. Due to the limitation of processing technology, the fin height should be less than the radius of the base tube. If it is necessary to make a high fin, it can be made into a serrated fin. So High-frequency welded finned tubes have two types, one is High-frequency welded solid finned tube and the other is High-frequency welded serrated finned tube. Now it is widely used in electric power, metallurgy, water and petrochemical industries.
High frequency welded finned tube is a new type, wear-resistant and efficient heat exchange material and an efficient and energy-saving heat exchange element. It uses the national patented technology and high-frequency welding production process to heat the steel strip and steel pipe at the same time with the high-frequency power supply as the heat source, so that they can be fused and welded together. It has the characteristics of high heat exchange efficiency, large heat dissipation area, long service life, wide temperature range and high pressure bearing. The production process is to wind the 0.8-1mm thick strip steel on the finned tube and adopt high-frequency welding
On the tube, the joint strength between the tube and the fin is ensured, and the metal thermal strength has reached 1.10~1.20w/kg ℃.
Advantages of high-frequency welded finned tubes
1. The installation is simple and economical. The length of high-frequency welding spiral finned tube can reach 6m, reducing the connection points, making the installation economical and fast, and reducing the probability of water leakage at the connection.
2. The maintenance is simple. After the installation of high-frequency welding spiral finned tube, the maintenance is basically unnecessary.
3. High efficiency. High frequency welding of spiral finned tube is the full contact welding between fins and steel pipes. The heat dissipation area is more than 8 times that of smooth tube. The internal is smooth and the internal water flow resistance is small.
4. Long service life, high mechanical strength of the combination of fins and pipes, and tensile strength of more than 200Mpa. The inside and outside of the pipes are all hot-dip galvanized.
Material of weldable fins: carbon steel, corrosion resistant steel, stainless steel, alloy steel.
Application of high-frequency welded finned tube
High frequency welded finned tube is an efficient heat transfer element. Its heat transfer area is several to dozens of times that of the bare tube, which can enhance heat transfer, reduce flow resistance, and reduce metal consumption, thus improving the economy and operation reliability of the heat exchange equipment.