What is EN AW-5083?

EN AW-5083, chemical designation EN AW-Al Mg4,5Mn0,7, is a wrought aluminium alloy with about 4.5 % magnesium and some manganese. It cannot be hardened by heat treatment: its strength comes from magnesium in solid solution and from cold work. The temper that follows the designation fixes that condition, for example O or H111 (annealed, then slightly strain-hardened by levelling or stretching) or H116 and H321, strain-hardened tempers for marine plate that carry corrosion requirements. It is mostly sold as rolled plate, less often as drawn or extruded bar or sections.

What do the properties of EN AW-5083 depend on?

Properties depend on temper and product form. 5083 holds up well in seawater and in damp, salty environments. In long-term service above about 65 °C, alloys with more than 3 % magnesium can become sensitised: a magnesium-rich phase forms on the grain boundaries and leaves the alloy prone to intergranular corrosion and stress corrosion cracking. At those temperatures 5083 is not an obvious choice. It welds well by MIG and TIG with a matching AlMg filler. In a strain-hardened temper, though, the heat-affected zone drops back to roughly annealed strength, particularly in yield strength; in O or H111 the loss is small. In machining, 5083 is gummier than 6082-T6, especially in soft tempers, which means longer chips and a tendency to built-up edge. Sharp cutting edges with positive rake help.

What does the standard say about EN AW-5083?

The designation follows EN 573: part 1 for the numbering system, part 2 for the chemical-symbol designation, part 3 for the chemical composition. Strength is only fixed once the temper to EN 515 and the product standard are known: for plate, EN 485-2 gives mechanical properties per temper and thickness; for drawn and extruded bar, EN 754-2 and EN 755-2. A drawing that only says EN AW-5083 therefore leaves the temper open. AW denotes wrought material; casting alloys are designated EN AC. The material certificate, usually a 3.1 to EN 10204, states which standard and temper were supplied.

How does EN AW-5083 behave in the shop?

5083 is chosen mainly for welded structures, marine and transport work, and parts that serve in salty or damp conditions. For milled parts with tight dimensional tolerances the product form matters too: rolled plate can distort from residual stress when a lot of material comes off one side. Cast plate of a similar composition is then an alternative, provided the customer approves the substitution. The alloy can be anodised, though the result often looks different from 6xxx alloys, and how even the finish comes out depends on temper, product form and the anodiser. Where appearance is specified, agree a sample beforehand.

What is EN AW-5083 often confused with?

EN AW-5083 is not 6082. 6082 is a precipitation-hardening AlMgSi alloy that gets its T6 strength from heat treatment and loses much of it in the heat-affected zone when welded; 5083 is not heat-treatable and keeps relatively more of its strength after welding. Nor is cast plate with a 5083-like composition the same as rolled EN AW-5083: it is a cast product with different properties and is not covered by the rolled-plate standard.