Copper Evaporator Tube

Compared with aluminum tubes, what are the advantages and disadvantages of copper evaporator tubes?

Technical advantages of copper evaporator tubes
1. Excellent thermal conductivity
The thermal conductivity of copper is about 397 W/(m·K), which is significantly higher than that of aluminum, about 237 W/(m·K), which means that under the same conditions, copper evaporator tubes can conduct the heat of the refrigerant more quickly and effectively. This advantage is particularly important in energy-saving air conditioners, industrial cooling and high-efficiency heat pump systems.
2. Higher strength and pressure resistance
Copper materials have higher mechanical strength, especially in thin-walled pipe designs, they can better resist the impact of high-pressure refrigerants and are not prone to cracking or deformation. This feature makes copper evaporator tubes more suitable for the new generation of high-pressure environmentally friendly refrigerant (such as R410A, CO₂, etc.) systems.
3. Excellent corrosion resistance and service life
Copper has natural oxidation resistance and pitting resistance, and can maintain stable performance in humid and corrosive environments. Especially in scenarios such as seaside, industrial areas or using salt water cooling systems, copper evaporator tubes show better life guarantees.
4. Easy processing and diversified structural design
Copper tubes have good ductility and formability, and can be processed into complex structures such as internal threaded tubes, flat tubes, finned copper tubes, etc., to optimize the heat exchange efficiency of the inner surface. Zhejiang Jingliang Copper-Tube Products Co., Ltd has long focused on the production of high-performance internal rib copper tubes and precision copper capillaries.
5. Reusable, environmentally friendly and recyclable
Copper has high recycling value and strong reusability. It is in line with the current trend of green manufacturing and sustainable development under the "dual carbon" strategy, and is also one of the reasons why many developed countries in Europe and the United States still favor copper.
Potential disadvantages of copper evaporator tubes
Although copper has many advantages, it also has certain limitations in certain scenarios and cost-driven:
1. Relatively high material cost
Copper prices fluctuate greatly, and the overall cost is usually higher than aluminum. For the low-end market that pursues cost control, such as some low- and medium-end household air conditioners and refrigerator products, aluminum has a certain appeal.
2. Heavy weight
The density of copper is 8.96 g/cm³, which is significantly higher than the 2.70 g/cm³ of aluminum. In areas with strict weight requirements (such as automotive air conditioning and aviation systems), aluminum tubes can reduce the overall load of the system and improve energy efficiency.
3. The connection process is more complicated
Although copper tubes have good welding performance, in some automated production lines, the brazing connection of copper tubes is slightly disadvantageous in terms of cost and efficiency compared with the mechanical expansion process of aluminum tubes. However, this problem is being gradually solved through the continuous technological upgrades of enterprises such as Zhejiang Jingliang in intelligent manufacturing.

What are the common defects and control measures of copper evaporator tubes in the welding process?

Common defects in the welding process of copper evaporator tubes
1. Porosity
Porosity is one of the most common problems in copper tube welding, usually caused by oil, moisture, oxides or impure shielding gas in the welding area. These tiny holes will weaken the airtightness of the weld and affect the pressure resistance and service life of the evaporator.
2. Lack of Fusion
This defect is manifested as incomplete bonding between the base material and the solder, usually caused by insufficient welding temperature, uneven heating or improper operation. Lack of fusion will cause the structural strength to decrease and easily lead to leakage risk.
3. Weld Cracks
Cracks usually occur during the cooling process, mainly due to excessive thermal stress, mismatch of welding materials or too fast cooling speed after welding. Once cracks occur, they are extremely difficult to repair, which seriously affects the safety of use.
4. Slag Inclusions
Slag inclusions are non-metallic impurities entrained in the welding molten pool, which may come from solder, flux residue or contaminants on the surface of the copper tube, affecting the strength and corrosion resistance of the weld.
5. Poor Wetting
The solder fails to evenly wet the joint surface, often because the oxide film on the surface of the copper tube is not cleaned or heated insufficiently, resulting in an unreliable solder joint and increasing the probability of desoldering.
Control measures and process optimization of common defects
1. Surface pretreatment-prerequisite guarantee of welding quality
The copper evaporator tube should be strictly cleaned before welding, including degreasing, deoxidation film and drying. Zhejiang Jingliang Copper-Tube Products Co., Ltd uses multiple pretreatment processes, including automatic cleaning systems and plasma surface treatment, to effectively avoid pollution sources in the early stage of welding.
2. Reasonable selection of flux and solder
High-quality flux can effectively remove the surface oxide film and improve welding wettability. Zhejiang Jingliang uses internationally certified environmentally friendly halogen-free flux and silver-based or phosphor copper-based solder to match the welding scheme according to different pipe diameters and process requirements to ensure welding strength and corrosion resistance.
3. Precise temperature-controlled welding equipment
Welding temperature control is the key to preventing unfusion and cracks. Zhejiang Jingliang introduced an intelligent temperature-controlled brazing system, combined with infrared temperature measurement and real-time monitoring technology, to achieve precise control of welding temperature within the range of ±5℃, greatly improving welding consistency.
4. Optimize welding process
For copper tubes of different specifications, formulate personalized process parameters (such as welding time, gas flow, preheating time, etc.), and through continuous improvement of advanced processes such as pulse brazing and laser-assisted welding, significantly reduce the welding defect rate.
5. Nondestructive testing and automated quality inspection
In order to ensure that each welded copper tube meets the standard requirements, Zhejiang Jingliang is equipped with eddy current flaw detection, X-ray nondestructive testing system and pressure sealing test line to achieve full quality tracking from welding to finished product delivery.

What are the main steps in the production process of copper evaporator tubes?

Raw material preparation for copper evaporator tube production
The starting point of copper evaporator tube production is high-quality copper. Relying on the advantages of a complete industrial chain, Zhejiang Jingliang has its own smelting and copper material procurement channels to ensure that the purity and physical properties of raw copper meet the standard requirements. Commonly used raw materials include high-purity oxygen-free copper and specific copper alloys, which lay a solid foundation for subsequent processing.
Extrusion molding
The first step in the production process is the extrusion of copper. After high-temperature heating, the copper billet is extruded into a round tube billet to achieve the basic tube diameter and wall thickness specifications. Zhejiang Jingliang uses advanced extrusion equipment and a scientific temperature control system to ensure the stability of the tube billet size and surface quality, preparing for subsequent drawing processing.
Heat treatment annealing
The extruded copper tube billet needs to go through the annealing process to improve the metal's organizational structure, enhance plasticity and toughness, and facilitate subsequent drawing and forming. Zhejiang Jingliang Copper-Tube Products Co., Ltd has a modern continuous annealing line that can achieve precise control of temperature and atmosphere, avoid oxidation and impurity intrusion, and ensure uniform performance of the copper tube.
Cold drawing process
The annealed copper tube enters the cold drawing process, and the copper tube is gradually drawn to the design specifications using a drawing machine. This process requires multiple drawing passes, combined with multiple annealing, to control the tube diameter and wall thickness accuracy. Zhejiang Jingliang uses its own high-precision drawing technology to ensure that the product has a small dimensional tolerance and high surface finish.
Finishing and surface treatment
In order to further improve dimensional accuracy and surface quality, the copper evaporator tube will undergo a finishing process. This step adjusts the outer diameter and wall thickness of the tube by multi-roll pressing. The subsequent surface treatment steps include cleaning, degreasing, rust removal and drying to ensure that the tube is free of oil and oxide layer, providing a clean surface for welding or subsequent processes.
Internal rib (internal thread) processing
The heat exchange efficiency of copper evaporator tubes depends largely on the structure of the inner surface. The internal rib copper tubes produced by Zhejiang Jingliang adopt advanced internal thread forming technology to form a regular thread structure on the inner wall of the tube, increase the heat exchange area and improve the flow state of the refrigerant, thereby significantly improving the evaporation efficiency and system performance.
Welding and connection processing
Some copper evaporator tubes need to be welded or brazed with other accessories. Zhejiang Jingliang is equipped with intelligent welding equipment and strict process standards to ensure stable and reliable welding quality and avoid leakage and structural defects. Its intelligent manufacturing system monitors welding parameters in real time to ensure the welding pass rate of each copper tube.
Quality inspection
Zhejiang Jingliang implements full-process quality control, from raw material inspection, size inspection, non-destructive testing to pressure testing. Especially for the air tightness and pressure resistance of evaporator tubes, the company uses advanced water pressure testing, air tightness testing and eddy current flaw detection equipment to ensure that the products fully meet industry standards and customer customization requirements.
Packaging and warehousing
The copper evaporator tubes that have passed strict inspection enter the packaging stage, and use moisture-proof and shock-proof professional packaging materials to ensure that they are not damaged during transportation. Zhejiang Jingliang is located in Tangpu Town, the "Hometown of Copper Tubes in East China", adjacent to Shangsan Expressway and National Highway 104, and only about 70 kilometers away from Hangzhou and Ningbo. The logistics and transportation are fast and convenient, effectively supporting the timely delivery of customers across the country and even around the world.