The heat exchange tube is the heat exchange element of the heat exchanger. The quality and performance characteristics of the heat exchange tube will affect the heat exchange work and heat exchange efficiency. Therefore, in order to better use the heat exchange tube, it is necessary to Choose carefully and deal with it correctly. Under normal circumstances, we recommend that you choose stainless steel heat exchange tube because it has good corrosion resistance; and the treatment of stainless steel heat exchange tube mainly includes: heat treatment, grinding treatment, pickling passivation, etc., among which heat treatment Is more important. So, do you know how the heat treatment of stainless steel heat exchange tubes is done? Next, SEKO Machinery will show you all.
The structure of the stainless steel tube can be changed by heat treatment, and the machinability can be changed. For example, the 06Cr19Ni10 stainless steel heat exchange tube has a low carbon content. Even if normalizing is used, it is difficult to achieve the required surface roughness of the tooth shaper, and the tool life is reduced. The low-carbon martensite and ferrite structure are obtained after incomplete quenching, and the hardness (HRC20～25) is improved. Not only the surface roughness meets the requirements, but the life of the stainless steel heat exchange tube is increased by 3 to 4 times, so for better The use of stainless steel heat exchange tubes requires heat treatment of the stainless steel tubes.
The correct selection of the heat treatment process by the stainless steel pipe factory can effectively improve the grinding performance of the steel. For example, strictly controlling the mass fraction of carbon in the carburized layer (not exceeding W=1.10%), eliminating network carbides, etc., can improve heat transfer Grinding performance of the tube.
The heat treatment of stainless steel heat exchange tubes in foreign countries generally uses a non-oxidation continuous heat treatment furnace with protective gas. The intermediate heat treatment in the production process and the final heat treatment of the finished product are carried out. As a bright surface without oxidation can be obtained, the traditional acid is eliminated. Washing process, the use of this heat treatment process not only improves the quality of steel pipes, but also overcomes the environmental pollution caused by pickling.
According to the current world development trend, bright continuous furnaces are basically divided into three types:
(1) Roller hearth type bright heat treatment furnace. The protective gas that can be used for this furnace type is high-purity hydrogen, decomposed ammonia and other protective gases. It can be equipped with a convection cooling system to cool the steel pipe faster. It is suitable for heat treatment of large-size and large-scale steel pipes. The hourly output is 1.0 tons. the above. Hangao Tech (SEKO Machinery) is very specialized in the field of this roller-hearth continuous coil bright annealing furnace. In addition to the synchronization of the front and rear traction speed of the whole line, we have done a very good job in temperature control accuracy and air tightness. The leading domestic stainless steel heat exchange tube manufacturer has become a loyal user of our brand.
(2) Mesh belt type bright heat treatment furnace, this furnace type is suitable for small diameter thin-wall precision steel pipe. The hourly output is about 0.3-1.0 tons, and the length of steel pipe can be up to 40 meters, and it can also process capillary tubes in coils.
(3) Muffle type bright heat treatment furnace. It is to install the steel pipe on a continuous rack and run heating in the muffle tube. This heat treatment method can process high-quality small-diameter thin-walled steel pipes at a lower cost, and the hourly output is about 0.3 tons or more.
