What Makes 5052 a Corrosion-Resistant Alloy
5052 belongs to the 5xxx Al-Mg family, with magnesium at 2.2-2.8% and chromium at 0.15-0.35% under ASTM B209/B209M. The magnesium addition is the main reason for the alloy's performance in wet and chemically aggressive service: it promotes a dense, self-repairing oxide film on the surface that is more stable than the film on pure aluminium, and the chromium addition refines the microstructure and improves resistance to stress corrosion cracking.
Unlike the 6xxx and 7xxx families, 5052 does not depend on alloying phases for strength, so there is no copper-rich constituent to set up galvanic cells. This is why it holds up in chloride environments where a higher-strength alloy would need protective coating.
The H116 Question and Marine Service Tempers
The H116 designation has a precise home: ASTM B928/B928M defines it for high-magnesium alloys containing 3% or more magnesium, such as 5083, 5086, 5383 and 5059, along with H321. Alloy 5052 carries 2.2-2.8% magnesium, so H116 is not a standardised temper for it. Where a drawing calls for 5052 in a marine service condition, the practical supply route is a documented mill condition aligned to ASTM B209/B209M tempers such as H32 or H34, with the sensitisation evidence supplied through ASTM G67 nitric acid mass loss testing and the visual exfoliation assessment of ASTM G66.
This distinction matters in procurement because the acceptance test, not the temper label, is what proves corrosion performance in service. Buyers specifying 5052 for seawater duty should require G67 mass loss data on the supplied lot rather than relying on a temper name.
Specification Data for 5052 Plate
Composition limits are taken from ASTM B209/B209M and match EN 573-3 for EN AW-5052.
| Element | Mg | Cr | Si | Fe | Cu | Mn | Zn |
|---|---|---|---|---|---|---|---|
| Content, % | 2.2-2.8 | 0.15-0.35 | 0.25 max | 0.40 max | 0.10 max | 0.10 max | 0.10 max |
| Property, H32 condition | Value |
|---|---|
| Tensile strength min, MPa | 215 |
| 0.2% proof stress min, MPa | 170 |
| Elongation min, % (thin sheet) | 7-12 depending on gauge |
| Density | 2.68 g/cm³ |
| Electrical conductivity | About 35% IACS |
| Melting range | About 607-650 °C |
H32 is the most widely stocked condition: strain hardened and stabilised, which fixes the mechanical properties well enough for formed and welded parts without the springback problems of harder tempers.
Applications in Marine and Chemical Plant
Marine: hulls and decks of small craft, superstructures, gangways, tanks and fittings that see splash and salt spray.
Chemical and process: storage tanks, reactor cladding, piping and ducting for mildly corrosive media, heat exchanger components.
Transport: fuel and water tanks for trucks and buses, trailer panels, RV bodies.
General engineering: pressure vessels working at moderate temperature, cryogenic insulation jacketing, electrical enclosures.
Consumer and architectural: cooking utensils, signage, appliance panels and cladding.
The alloy performs best in neutral and mildly acidic chloride environments. Strong alkalis and hot concentrated acids will attack aluminium regardless of alloy, so 5052 is not a blanket answer for every chemical service condition.
Fabrication, Welding and Quality Control
5052 is one of the easiest 5xxx alloys to fabricate. It cold forms to complex shapes, machines acceptably, and welds reliably with ER5356 or ER4043 filler to AWS A5.10. Formed and welded assemblies are commonly used as-welded without post-weld treatment, which is a significant cost advantage in tank and vessel work.
Anodising thickens the natural oxide film and is often specified for exterior architectural and marine fittings; EN ISO 7599 gives the coating specification framework. Where the part will be painted, a conversion coating improves adhesion on the mill finish surface.
Chemical composition verified per cast against ASTM B209/B209M.
Tensile and proof stress tested per production lot.
ASTM G67 mass loss reported where intergranular corrosion resistance must be demonstrated.
Surface inspected for roll marks, scratches, oil spots and edge burrs before packing.
Mill test certificate to EN 10204 3.1 with heat number and mechanical data.
Frequently Asked Questions
Q: Is H116 a valid temper for 5052?
A: H116 is defined in ASTM B928/B928M for high-magnesium alloys with 3% or more magnesium, so 5052 at 2.2-2.8% magnesium is normally supplied in ASTM B209 tempers such as H32 or H34 for marine work.
Q: Why does 5052 resist seawater so well?
A: Magnesium in the alloy produces a dense, stable surface oxide film, and the low copper content removes the galvanic cells that drive pitting in other alloy families.
Q: What strength does 5052-H32 offer?
A: Minimum tensile strength of 215 MPa and minimum 0.2% proof stress of 170 MPa under ASTM B209/B209M, which is roughly two thirds of the strength of 5083.
Q: Can 5052 be welded without post-weld treatment?
A: Yes. ER5356 or ER4043 filler per AWS A5.10 produces sound joints, and tank and vessel work is commonly left as-welded.
Q: How is intergranular corrosion resistance demonstrated for a supplied lot?
A: By ASTM G67 nitric acid mass loss testing, supported where required by the ASTM G66 visual exfoliation assessment.
Q: Which chemicals should be avoided with 5052 equipment?
A: Strong alkalis and hot concentrated acids, which break down the protective oxide film; the alloy is intended for neutral and mildly acidic chloride service instead.
