Metal round cans are widely used in the food and chemical industries due to their high barrier properties, mechanical strength, and recyclability. However, extreme temperature environments (such as high-temperature sterilization or low-temperature refrigeration) can easily cause can deformation, leading to seal failure or structural damage, directly affecting product safety and shelf life. Therefore, researching the deformation control and structural stability of metal round cans under extreme temperatures has become a key issue in ensuring their reliability.
The coefficient of thermal expansion of metallic materials is the fundamental cause of deformation. When the ambient temperature changes drastically, different parts of the can experience uneven expansion or contraction due to the temperature gradient, which in turn induces internal stress. For example, in high-temperature environments, the vibration of metal atoms intensifies, the lattice spacing increases, and the radial expansion of the can may cause the rolled edge structure to loosen; while in low-temperature environments, the material's toughness decreases and its brittleness increases, making the can prone to cracking due to contraction stress. If this thermo-mechanical coupling effect is not effectively controlled, it will directly damage the can's sealing and pressure-bearing capacity.
To suppress deformation caused by extreme temperatures, it is necessary to address both material selection and process optimization. At the materials level, using alloys with low coefficients of thermal expansion (such as aluminum alloys) or balancing thermal stress through composite structures (such as steel-aluminum bimetallic cans) can significantly reduce the risk of deformation. At the process level, annealing can eliminate residual processing stress and improve material uniformity; while controlling the can wall thickness and aspect ratio can optimize heat conduction paths and reduce temperature gradients. Furthermore, improvements in the edge-rolling process (such as using a double-rolled edge structure) can enhance the mechanical strength of the joints and prevent seal failure due to thermal expansion and contraction.
Structural stability design must consider both static pressure bearing and dynamic temperature shock. In static scenarios, the can must withstand the weight of the contents and external pressure (such as stacking loads). In this case, finite element analysis is needed to optimize the can wall thickness distribution and ensure strength redundancy in stress concentration areas (such as the transition between the can bottom and sidewalls). In dynamic temperature shock scenarios (such as rapid freezing or high-temperature sterilization), the stress-strain behavior during thermal cycling needs to be simulated, and stress peaks can be reduced by adjusting can geometric parameters (such as fillet radius). For example, increasing the fillet radius at the can bottom can disperse local stress and prevent crack initiation. The impact of extreme temperature environments on the sealing performance of tanks cannot be ignored. At high temperatures, gaskets may soften and lose elasticity, leading to loosening of the rolled edge structure; at low temperatures, gasket hardening may cause peeling of the sealing surface. Therefore, it is necessary to select appropriate sealing materials (such as silicone rubber or fluororubber) according to the temperature range, and to balance sealing performance and temperature resistance by optimizing gasket thickness and compression ratio. Furthermore, the fit precision between the tank and the lid (such as radial clearance) must be strictly controlled to avoid excessively loose or tight fits due to thermal expansion and contraction.
Experimental verification is a crucial step in evaluating the effectiveness of deformation control. Temperature shock tests (such as rapid switching from -40℃ to 121℃) can simulate extreme operating conditions in actual use, allowing observation of tank deformation, sealing failure, and crack propagation. Simultaneously, 3D scanning technology can quantify the degree of deformation, providing data support for structural optimization. For example, one study compared the sealing performance of tanks with different rolled edge structures after high-temperature sterilization, finding that the leakage rate of the double-rolled edge structure was significantly lower than that of the traditional structure, verifying the effectiveness of the process improvement.
Future research can further explore the application of smart materials and novel structures. For example, shape memory alloys can recover their original shape through temperature triggering, thereby actively compensating for deformation caused by thermal expansion and contraction; while honeycomb sandwich structures can improve the impact resistance of cans through lightweight design. Furthermore, combining digital twin technology can enable full life-cycle simulation of cans under extreme temperatures, providing precise guidance for personalized design.
Research on deformation control and structural stability of metal packaging round cans under extreme temperatures requires collaborative advancement from multiple dimensions, including materials, processes, structures, and experimental verification. By optimizing thermal expansion matching, strengthening sealing design, and introducing smart materials, the reliability of cans under extreme conditions can be significantly improved, providing safer packaging solutions for food preservation, chemical storage, and other fields.
