Due to its good electrical and thermal conductivity, anti-magnetic properties and resistance to atmospheric corrosion, TP2 copper violet tube is widely used in refrigeration tubes for air-conditioners and refrigerators, water tubes, tubes for condensers, evaporators and heat exchangers, vapor tubes, and tubes for distillation devices. In recent years, with the rapid development of the air conditioning and refrigeration industry, people have put forward more stringent technical requirements for TP2 copper tubes, the key material for heat exchangers in air conditioning and refrigeration equipment. Not only the requirements of copper tube fine diameter, thin-walled, efficient heat transfer, high cleanliness, but also on the microstructure and mechanical properties of copper tube has also developed a strict technical standards.
Annealing plays a vital role in the whole production process of copper tube, which not only improves the surface cleanliness of copper tube, but also controls the internal microstructure and improves the mechanical properties of copper tube. In response to these new technical standards, many engineers and technicians have conducted in-depth research on the copper tube annealing process. In terms of improving the surface cleanliness of copper tube, Li Wei started from the two main factors affecting the surface brightness of copper tube annealing, and through the annealing process experiments proposed that the use of acidic cleaning agent to remove the oil on the surface of the copper tube before annealing and the selection of suitable protective gas during the annealing process can help to improve the brightness of the surface of the copper tube. Liao Nanlian et al. conducted an experimental study on three different blowing methods on a bell-type furnace and found that the hot blowing method has the most ideal effect on improving the cleanliness of the inner surface of copper tubes. In terms of improving the organization and mechanical properties of copper tubes, Zhu Maoxiang solved the phenomenon of hardening of copper tubes, which often occurs in the annealing of pit-type furnaces, by improving the structure of the material rack and the length of the internal blowing inlet. Liu Zhanhai and other experiments to compare and analyze the online annealing furnace induction frequency on the surface quality of the female pipe thread and production efficiency, the results show that the use of medium-frequency induction annealing that can get a bright surface, the internal organization is uniform, excellent mechanical properties of the female pipe, but also to maintain a high production efficiency.
Currently, due to the limitations of the factory testing equipment and the confined nature of the annealing environment, a series of changes that occur during the annealing process, such as temperature field changes and tissue evolution can not be directly, dynamically, continuously observed, and indirectly observed is also very difficult. As a result, most of the research on the copper pipe annealing process is from the macro aspects of the beginning, while the micro aspects of the mechanism of change is not enough research, insufficient understanding.
With the development of air-conditioning and refrigeration industry, there is no doubt that the demand for copper tubes will increase substantially, the technical requirements of copper tubes will be more demanding, and then simply rely on the traditional research methods to improve the quality of copper tube products have not met the user's needs, annealing process research and the combination of computer technology will be a fast, economical and efficient research methods.
