When sourcing marine-grade aluminum for naval vessel construction on Alibaba.com, understanding the specific temper designation is crucial. The "H128" in 5083-H128 isn't just a random code—it represents a specialized heat treatment developed specifically for extreme marine environments. This temper was introduced by Aleris in November 2013, responding to US Navy requirements for aluminum plates that could withstand the most demanding saltwater conditions [5].
The 5083 alloy itself belongs to the 5xxx series of aluminum alloys, characterized by magnesium as the primary alloying element. What sets 5083 apart is its magnesium content ranging from 4.0% to 4.9%, combined with 0.40-1.0% manganese and 0.05-0.25% chromium [6]. This specific chemical composition delivers the highest strength among all 5xxx series alloys, making it the preferred choice for shipbuilding applications where structural integrity cannot be compromised.
The H128 temper designation indicates enhanced thermal stability that prevents sensitization—a critical concern for marine aluminum. Sensitization occurs when aluminum is exposed to elevated temperatures (typically 50-200°C) for extended periods, causing chromium-rich precipitates to form along grain boundaries. This makes the material susceptible to intergranular corrosion, particularly dangerous in saltwater environments. The H128 treatment specifically addresses this vulnerability, maintaining corrosion resistance even after thermal exposure [7].
"This new innovation meets the requirements of our marine and shipyard customers who need an aluminum plate solution that can meet this standard of corrosion resistance in the most extreme conditions." [5]
