How stable is the thermal conductivity of corrugated radiator tubes in automotive components under different temperature conditions?
Publish Time: 2025-08-11
In automotive thermal management systems, corrugated radiator tubes, as key heat transfer elements connecting heat sources and cooling media, directly affect the temperature control efficiency of the engine, transmission, battery, and electric drive system. The stability of thermal conductivity—the core parameter of a material's ability to conduct heat—over a wide temperature range directly determines the reliability of the cooling system under cold starts, high loads, or extreme climates.
1. Mainstream Material Selection: Metals Dominate, Balancing Thermal Conductivity and Formability
Currently, automotive corrugated radiator tubes are primarily manufactured using metal materials, with aluminum alloys being the dominant choice. Stainless steel or copper alloys are used in some high-performance or special-purpose applications. These materials are chosen not only for their good corrosion resistance and machinability but, more importantly, for their high intrinsic thermal conductivity and its gradual change over a wide temperature range.
2. Mechanism of Temperature's Influence on Thermal Conductivity
The thermal conductivity of metallic materials is mainly contributed by the movement of free electrons. As temperature increases, lattice vibrations intensify, enhancing the scattering of electron motion and leading to a slight decrease in thermal conductivity. However, for structurally stable metals, this decrease is continuous, predictable, and limited in magnitude. More importantly, bellows do not transfer heat in isolation during service but are coupled with the coolant via forced convection. The overall heat transfer efficiency is more influenced by the convective heat transfer coefficient, and small fluctuations in the material's thermal conductivity have a limited impact on system-level performance.
Automotive bellows are mostly manufactured using hydroforming or roll forming processes, which may introduce residual stress or texture. To ensure stable thermal performance, finished products typically undergo stress-relief annealing to eliminate work hardening and restore a uniform grain structure. A stable microstructure means that during long-term thermal cycling, there will be no abrupt changes in thermal conductivity due to phase transformation, precipitation, or recrystallization. Furthermore, although the surface oxide film is a poor conductor of heat, its thickness is only a few nanometers, and its impact on overall thermal conductivity is negligible. If further improvement in interfacial thermal conductivity is required, micro-arc oxidation or thermally conductive coatings can be used for optimization.
4. Empirical Performance Under Extreme Conditions
In the application of battery cooling plates in new energy vehicles, corrugated aluminum tubes often need to frequently switch between -30℃ and 60℃. Extensive bench testing shows that their transient thermal response curves are highly repetitive, with no significant performance degradation, proving that their thermal conductivity stability is sufficient to support precise temperature control requirements. Similarly, in engine EGR coolers, facing the interlayer heat transfer between exhaust gas above 200℃ and coolant at 80℃, aluminum alloy corrugated tubes can still maintain reliable operation for tens of thousands of hours, with no cases of localized overheating failure due to thermal conductivity degradation observed.
In summary, the aluminum alloy and other metal materials used in corrugated radiator tubes for automotive components exhibit excellent stability in thermal conductivity within typical automotive operating temperature ranges—small fluctuations, predictable trends, and high long-term reliability. This stability stems from the intrinsic physical properties of the metal, mature heat treatment processes, and a rigorous engineering verification system. It is this "silent reliability" that makes the corrugated radiator tube a trustworthy heat transfer bridge in the automotive thermal management system, continuously protecting the safety and efficiency of the power core between the limits of cold and heat.
