Can stainless steel welded tubes be used as heat exchanger tubes?
In the past five years, the development trend of stainless steel welded pipes is relatively good, and great progress has been made in all aspects of scale, quality and production technology, especially its demand area is gradually expanding. In addition, as the stainless steel welded pipe technology becomes more and more mature, stainless steel seamless pipes can be gradually replaced in many applications, such as heat exchanger equipment pipes, medium and low pressure boiler pipes, etc.
1. Production characteristics of stainless steel pipe welding equipment: light production equipment, low investment, fast construction, simple welding methods, complete product specifications, high dimensional accuracy, small wall thickness deviation, surface smoothness, and high yield. In the case of mass production, welded pipes are 20% lower than seamless pipes. In recent years, the domestic technology of "welding-cold-rolling" stainless steel pipes has been adopted in China. Cold-rolled coils have been used for longitudinal shearing and upsetting according to specifications. Welded into a pipe by a multi-gun argon arc welding machine and then cold-rolled (pulled) to make welding. The performance index of the seam is basically consistent with the base material, and the product quality is significantly improved. Therefore, the advantages of using stainless steel welded pipes instead of stainless steel seamless pipes are becoming more and more obvious.
2. Advantages of stainless steel welded pipe production: First, in the production process of stainless steel welded pipe, the pipe body is evenly squeezed, and then online bright solid annealing is performed, the surface becomes very smooth, the surface is smooth and easy to expand, and it has antifouling function. . This facilitates heat dissipation, does not require frequent cleaning, saves time and effort, and saves money. Secondly, welded pipe is a deep-processed product of sheet metal. Its uniform wall thickness has unparalleled advantages. It can also be arbitrarily fixed with high accuracy. Similarly, stainless steel is corrosion resistant and has a long service life.
3. Current status of stainless steel welded pipe products: China's industrial stainless steel welded pipe production capacity does not meet the domestic market demand. Most of the existing stainless steel welded pipe equipment units do not match the process equipment, such as lack of heat treatment and-line testing equipment, so that the unit's production capacity cannot be fully utilized. Generally, only general decorative pipes can be produced, and the low-end standard stainless steel decorative welded pipes in the market are in excess of demand; higher-standard industrial welded pipes, such as chemical machinery pipes and heat exchanger pipes, can only be produced by a few manufacturers, and the production capacity is seriously insufficient.
Can welded pipes work on heat exchange equipment?
NO.1, higher standard product tubes are possible. Heat exchanger tubes are an indispensable part of tube-tube heat exchange equipment. Heat exchanger tubes are usually selected based on pressure and fluid medium. One of the misunderstandings in selecting heat exchanger tubes on the market today is that stainless steel welded tubes cannot be used as heat exchanger tubes, but GB / 151-1999 clearly stipulates that stainless steel welded tubes can be used when the pressure of the tube is. ≤6.4MPa. Especially now that the production process of stainless steel welded pipes has been very mature, it can fully meet the needs of general heat exchanger pipes and show its unique advantages.
NO.2, mature production technology, stainless steel welded pipe will become the first choice
Since the heat exchanger tube forms the heat transfer surface of the heat exchanger, the size of the heat exchanger tube has a great influence on the heat transfer. When using a small-diameter tube, the heat exchange area per unit volume of the heat exchanger is large, the equipment is relatively compact, the metal consumption per unit heat transfer area is small, and the heat transfer coefficient is also high. Although it is troublesome to manufacture, the use of austenitic stainless steel welded pipe as a heat exchange tube can avoid the above problems, because austenitic stainless steel welded pipe has good corrosion resistance and smooth surface, and the production process is mature, so stainless steel welded pipe is heat exchange The first choice of tube.