What Makes 5454 Different
5454 is an aluminum-magnesium alloy with deliberately restricted magnesium content and higher manganese than its neighbours in the family. Magnesium at 2.4-3.0 % keeps strength useful while leaving enough solubility that the alloy does not sensitise in the way the high-magnesium grades do, and manganese at 0.50-1.0 % with a chromium addition stabilises the microstructure and improves resistance to stress corrosion cracking. The result is a moderate-strength alloy that can be used in welded structures at service temperatures where 5083 can no longer be trusted.
Chemical Composition
| Element | Range (wt %) |
|---|---|
| Magnesium | 2.4 - 3.0 |
| Manganese | 0.50 - 1.0 |
| Chromium | 0.05 - 0.20 |
| Silicon | 0.25 max |
| Iron | 0.40 max |
| Copper | 0.10 max |
| Zinc | 0.25 max |
| Titanium | 0.20 max |
| Aluminum | Remainder |
Mechanical Properties
| Property | 5454-O | 5454-H32 |
|---|---|---|
| Tensile strength, minimum | 215 MPa (31 ksi) | 250 MPa (36 ksi) |
| Yield strength, 0.2 % offset, minimum | 85 MPa (12 ksi) | 180 MPa (26 ksi) |
| Typical tensile strength | 230 - 250 MPa | 260 - 280 MPa |
| Elongation, 50 mm | 18 % minimum | 10 % minimum |
| Density | 2.69 g/cm3 | |
| Elastic modulus | 70 GPa | |
The minima above follow ASTM B209 for sheet and plate in the respective tempers, with tensile testing to ASTM E8/E8M; EN 485-2 carries the equivalent European requirements. Mill finish plate is normally supplied to the standard thickness, width and flatness tolerances of the governing product standard unless a tighter schedule is agreed at order stage.
Elevated Temperature and Stress Corrosion Behaviour
The practical reason 5454 is specified is sensitisation. In the high-magnesium grades, sustained exposure above roughly 65 degrees C precipitates beta phase at grain boundaries, and the material then becomes susceptible to intergranular corrosion and stress corrosion cracking under sustained tensile stress. Because 5454 contains less magnesium and more manganese, it remains resistant in the same temperature window and is therefore the standard substitute in hot service. Hot cargo tanks, hoppers, exhaust-adjacent structures and pressure vessels that operate above about 65 degrees C are the classic applications, and the alloy also holds strength better than 5052 as temperature rises. As with all work-hardened tempers, some strength is lost if service temperature is high enough to overage the cold work, so the design code's allowable stress values should govern.
Mill Finish Supply and Fabrication
Mill finish means the plate is supplied with the as-rolled surface, without polishing, brushing or coating; it is the normal, lowest-cost condition and is intended for painting, lining or straightforward structural use. Buyers should expect the usual rolled surface characteristics rather than a bright or decorative appearance, and should specify whether the material is to be supplied flat, stretched, or with a protective film on one or both faces.
Fabrication follows standard 5xxx practice. 5454-H32 shears, saws and machines without difficulty, bends to an inside radius of roughly one and a half times the thickness in the H32 temper, and welds with 5554 filler, which is the filler developed for this alloy and gives the best match in strength and hot-cracking resistance. 5356 is an acceptable general alternative. No post-weld heat treatment is required, and the heat-affected zone retains most of the parent-metal strength.
Typical Applications
Tank truck barrels and chemical transport vessels, especially those carrying hot or reactive cargoes; pressure vessels and process equipment; dump truck bodies and hoppers; road tanker frames; automotive and off-road wheel applications; and structural components that see both welding and moderate heat. Where the service temperature stays below about 65 degrees C and maximum strength is needed, 5083 is the better choice; where the temperature is higher or stress corrosion cracking is a design concern, 5454-H32 takes over.
Frequently Asked Questions
Q: Why choose 5454 instead of 5083?
A: Above about 65 degrees C, 5083 can sensitise and become susceptible to stress corrosion cracking, while 5454 remains resistant because of its lower magnesium content.
Q: What does mill finish mean on this plate?
A: The plate is supplied with the as-rolled surface, unpainted and unpolished, ready for painting, lining or direct structural use.
Q: Which filler metal is used to weld 5454?
A: 5554 filler is the standard choice because it matches the alloy's strength and resists hot cracking; 5356 is a general alternative.
Q: Does 5454 need post-weld heat treatment?
A: No. The alloy is not heat treatable, and post-weld thermal treatment is unnecessary and would only reduce the cold-worked strength.
Q: How does 5454-H32 form?
A: It bends to an inside radius of roughly one and a half times the thickness and machines and cuts easily, though it is less formable than 5052.
Q: Is 5454 suitable for marine use?
A: Yes, it resists sea water well and is often specified for marine components that also see elevated temperature, where 5083 is restricted.
