High cleanliness copper tube for refrigerator
High-cleanliness copper tubes for refrigerators are core components of the refrigeration system, primarily used in the evaporator, condenser, and connecting lines. Their cleanliness directly impacts the refrigerator’s cooling efficiency and service life. Made from high-purity oxygen-free copper, these tubes feature smooth, impurity-free inner surfaces and undergo rigorous degreasing and cleaning processes. This effectively prevents wear on the compressor, reduces refrigerant flow resistance, and ensures long-term, stable operation.
The production of high-cleanliness copper tubes for refrigerators requires multiple precision machining steps. First, oxygen-free copper billets are produced through horizontal continuous casting or the upward drawing method to ensure copper purity reaches above 99.99%, minimizing the impact of oxides on tube performance. Subsequently, the copper billets are processed into thin-walled copper tubes through cold rolling and stretching, with a wall thickness tolerance of ±0.02 mm to meet the efficient heat exchange requirements of the refrigeration system. The most critical cleaning step involves ultrasonic cleaning and high-pressure water flushing to remove impurities such as oil, metal debris, and other impurities from the inside and outside of the copper tubes. Cleanliness levels must reach NAS level 8 or higher, ensuring the absence of visible contaminants.
In terms of performance requirements, high-cleanliness copper tubes for refrigerators must not only possess excellent thermal conductivity but also good corrosion resistance and brazing properties. Due to the presence of refrigerants and lubricants in refrigerator refrigeration systems, the inner wall of the copper tubes must be resistant to corrosion caused by long-term contact. Furthermore, when connecting the pipes, the brazing between the copper tubes and fittings must ensure a secure, leak-free interface, requiring the copper tubes to possess excellent welding compatibility. Furthermore, to adapt to the trend toward lightweight refrigerator designs, the wall thickness of copper tubes is gradually decreasing. Currently, the wall thickness of mainstream products has been reduced from the traditional 0.7 mm to below 0.5 mm, further improving heat exchange efficiency while reducing material costs.
Different refrigerator types have different requirements for high-cleanliness copper tubes. The evaporators of direct-cooling refrigerators often use serpentine coils, requiring the copper tubes to have excellent bending properties to prevent cracking during bending. The condensers of air-cooling refrigerators use a finned-tube structure, requiring a tube expansion process to tightly bond the copper tubes to the aluminum fins. This places higher demands on the dimensional accuracy and hardness of the copper tubes. With the increasing popularity of inverter and smart refrigerators, the operating pressure and temperature fluctuation range of refrigeration systems have increased, driving the use of high-pressure, high-cleanliness copper tubes. These products utilize optimized heat treatment processes to increase the tensile strength of the tubes to over 300 MPa, meeting the demands of complex operating conditions.
In terms of industry development, the production of high-cleanliness copper tubes for refrigerators is moving towards greener, higher-performance manufacturing. Companies are improving smelting processes to reduce energy consumption and emissions during production. Furthermore, they are developing ultra-thin diameter and special-shaped copper tubes to further enhance the compactness and energy efficiency of refrigeration systems. With increasing global demand for energy conservation and environmental protection, refrigerator energy efficiency standards are constantly being upgraded, which will continue to drive innovation in high-cleanliness copper tube materials and provide strong support for the sustainable development of the refrigeration industry.
