Understanding Aluminium Alloy Sheet Series
Aluminium sheet and plate are grouped into series according to their main alloying elements. The 1xxx series is commercially pure aluminium; the 3xxx series uses manganese; the 5xxx series uses magnesium; the 6xxx series combines magnesium and silicon; and the 7xxx series adds zinc for very high strength. This classification directly affects mechanical properties, weldability, corrosion behaviour and surface finish, so it is the first decision point in material selection.
Grade-by-Grade Characteristics
6061 is a general-purpose structural alloy with medium-to-high strength, good weldability and excellent corrosion resistance, making it a default choice for frames, platforms and machined parts. 6063 offers slightly lower strength but superior extrudability and a smooth surface that accepts anodizing well, which is why it dominates architectural profiles. 6082 is a European-workhorse grade with strength comparable to 6061 and improved machinability in heavier sections. 5052 and 5083 are magnesium-rich marine grades with outstanding corrosion resistance; 5083 in particular is widely used for ship hulls, decks and welded pressure vessels because of its high strength in the welded condition. 7075 is a zinc-based aerospace grade with the highest strength in this group, specified where stiffness and load capacity outweigh cost and formability.
What Temper Designations Mean
Temper describes the mechanical state of the alloy after processing. O means fully annealed, giving maximum formability for deep drawing and bending. H tempers apply to strain-hardened non-heat-treatable alloys such as 3xxx and 5xxx; H14 is half-hard, H18 full-hard, and H32, H34, H36 and H38 are stabilized tempers for alloys like 5052 and 5083 that need controlled ductility. T tempers apply to heat-treatable alloys: T4 is solution heat treated and naturally aged, T6 is solution heat treated and artificially aged to peak strength, while T3 to T8 describe different combinations of working and aging. Specifying the correct temper is as important as choosing the grade, because it determines whether the material will bend, weld and perform as expected.
Typical Sizes and Specification Ranges
Cold rolled aluminium sheet is commonly supplied in thicknesses from about 0.20 mm to 3.5 mm, with widths around 1000 to 2650 mm and lengths of 2000 to 3000 mm. Hot rolled plate covers heavier sections, typically 12 to 260 mm thick, with widths up to 3800 mm and lengths up to 38000 mm depending on the mill. Grades such as 5005, 5052 and 5083 can be supplied across a very wide range, from thin foil-like gauges up to thick plate, in tempers from O through H12 to H116 and H321. Exact availability should always be confirmed with the supplier against the required gauge, width and quantity.
How to Choose the Right Grade
Start with the application environment. For saltwater exposure, welding and marine structures, choose 5083 or 5052. For general fabrication, machine frames and transport components, 6061 or 6082 offer the best balance of strength and workability. For architectural and anodized finishes, 6063 and 5005 produce bright, uniform anodized surfaces. When maximum strength per kilogram is required and formability is secondary, 7075 is the appropriate choice. Always confirm the required standard, such as ASTM B209 or EN 485, so that composition, tolerances and mechanical properties are clearly defined in the purchase specification.
FAQ
Q1: What is the difference between 6061 and 6063 aluminium sheet?
6061 has higher strength and is preferred for structural and machined parts, while 6063 has better extrudability and surface quality for architectural applications. Both are heat treatable to T6 and offer good corrosion resistance.
Q2: Can 5083 aluminium plate be welded without losing strength?
Yes, 5083 retains a high proportion of its strength after welding, which is why it is standard for shipbuilding and welded tank construction. Matching filler alloys should be selected according to the welding standard.
Q3: What does temper H116 mean for 5083?
H116 is a special temper developed for marine service, combining controlled strength with resistance to intergranular corrosion. It is commonly specified for boat hulls and offshore structures.
Q4: Is 7075 aluminium sheet suitable for welding?
7075 is not recommended for fusion welding because its high strength is lost in the heat-affected zone. It is usually joined by mechanical fasteners or adhesive bonding in aerospace applications.
Q5: Which aluminium alloy is best for anodizing?
Alloys with low alloying content, such as 6063, 5005 and the pure 1xxx grades, anodize to bright, uniform finishes. Magnesium-containing 5xxx alloys also respond well to clear anodizing.
Q6: What information should a buyer provide when ordering sheet or plate?
Specify the alloy grade, temper, thickness, width, length, quantity, surface finish and the governing standard. Providing the end application helps the supplier confirm the material is suitable.