The drink cans’ strength is obtained through the utilization of specific aluminum alloys, primarily 3004 and 3104, which provide the necessary strength, corrosion resistance, and light efficiency. They consist of approximately 95% to 98% aluminum, 1.0% to 1.5% manganese, and 0.8% to 1.3% magnesium, which enhance mechanical properties without compromising formability and economy.
The ironing and deep drawing (D&I) operation, employed in can production, demands aluminum capable of withstanding high-pressure forming without fracture. The 3004 aluminum alloy, commonly applied to the can body, possesses superior elongation and tensile properties, enabling it to resist internal carbonation pressures of over 90 psi (pounds per square inch). The 3104 aluminum alloy, which is often used on the can ends and tabs, provides additional rigidity and impact strength to make the can able to withstand stacking forces in the retail and distribution industries.
The strength of an aluminum can is not lost despite its light weight. A standard 12-ounce can would weigh approximately 13.5 grams, with an average wall thickness of 0.097 mm to 0.115 mm. This slender yet tough structure of material saves manufacturing cost and material waste, adding to overall manufacturing efficiency. Aluminum processing improvements since 1972 have reduced beverage can weight over 30%, allowing more cans to be made from an equivalent amount of raw material.
Durability is also a concern when it comes to corrosion resistance, especially for acid beverages like carbonated soft drinks and fruit juices. The aluminum can for beverages is coated with a polymeric or epoxy resin lining to prevent the beverage from coming into direct contact with metal. The interior coating, typically 1 to 2 microns in thickness, is for leach and oxidation protection, ensuring product safety and shelf life. In recent years, manufacturers have moved to BPA-free coatings under pressure from regulatory and consumer requirements for safe packaging materials.
Recyclability becomes a key attribute in maintaining aluminum’s strength along with increasing sustainability. The recycling rate of the world for aluminum is over 70%, of which the United States recycles over 105 billion cans yearly. Recyclable aluminum boasts 100% of its initial properties, while requiring 95% less energy compared to initial aluminum production. This high rate of recyclability maintains aluminum beer and soft drink cans structurally functioning through several life cycles.
Overseas demand for aluminum cans continues to increase as giants like Ball Corporation, Crown Holdings, and Ardagh Group continue to invest in greater alloy formulations with increased strength but decreased weight. Innovations in high-strength processing of aluminum make the cans thinner and stronger to withstand impacts. 3004 and 3104 aluminum alloys’ ability to resist mechanical stress, carbonation pressure, and environment place them most ideally suited for today’s beverage packaging requirements.
The shape of aluminum alloys in the case of cans for beverages is such that it would satisfy the requirements of balancing cost, strength, and recyclability so that the cans would be light but strong enough to endure transport, stacking, and storage conditions. Further information on what type of aluminum is used in beverage cans can be found at what type of aluminum is used in beverage cans.