Can 5083 aluminum be welded?
Yes. 5083 is one of the best aluminum alloys to weld: MIG or TIG with 5183 or 5356 filler, and it keeps its annealed strength across the weld.
5083 is a non-heat-treatable aluminum-magnesium alloy (about 4.0-4.9% Mg with manganese and chromium) and one of the most weldable structural aluminum alloys. It is the standard plate for boat and ship hulls, workboats, LNG and cryogenic tanks, pressure vessels and tank trailers. Its strength comes from magnesium in solid solution and from strain hardening, not from a precipitation heat treatment, so welding costs it only the strain hardening. A 5083-H116 plate with a minimum of 305 MPa (44 ksi) tensile keeps about 275 MPa (40 ksi) across the weld, the annealed (O temper) strength. By comparison, 6061-T6 drops from about 290 MPa (42 ksi) to 165 MPa (24 ksi) welded.
Filler choice is simple. ER5183 (AWS A5.10) is the standard match: it gives the full 275 MPa welded strength and keeps the corrosion resistance of the plate. ER5356 is widely stocked and works well, with slightly lower as-welded strength. ER5556 gives the highest strength. Do not use 4043 or 4047: silicon fillers form brittle magnesium silicide with high-magnesium alloys and the weld loses ductility. MIG with pulsed or spray transfer is the production process for plate; AC TIG is used for thin sheet, tube and root passes. Shield with argon, or an argon-helium mix for thicker sections.
Porosity is the main defect. Hydrogen from moisture, hydrated oxide, oil or damp wire dissolves in the pool and leaves gas pores, so degrease, stainless-brush the joint just before welding, and keep filler wire dry and sealed. Distortion is the other: aluminum expands about twice as much as steel, so sequence welds and fixture thin plate. Keep preheat and interpass low, commonly under about 120 °C (250 °F); preheat is used mainly to drive off moisture. One service limit applies to base metal and filler alike: 5xxx alloys with more than 3% magnesium, 5083 and the 5183 and 5356 fillers included, should not see sustained temperatures above about 65 °C (150 °F). Long exposure sensitizes them to intergranular corrosion and stress corrosion cracking. For hot service choose 5454 with ER5554 filler.
Welding for 5083 parts: where to send them
What to specify
- Base metal: 5083-H116 or H321 per ASTM B928 for marine service, or 5083-O/H111 per ASTM B209 for general fabrication
- Filler: ER5183 per AWS A5.10 (ER5356 acceptable at slightly lower strength, ER5556 for highest strength); no 4043 or 4047
- Welding code: AWS D1.2 for structures, ASME Section IX for pressure vessels, or the classification society rules for classed vessels
- Design strength across the weld on welded values, about 275 MPa (40 ksi) tensile, not the H116 plate values
- Service temperature: no sustained exposure above 65 °C (150 °F); use 5454 with ER5554 for hot service
- Inspection: visual plus radiographic, ultrasonic or dye penetrant where required, with porosity acceptance criteria
- Pre-weld cleaning (degrease and stainless brush) and dry, sealed filler wire
Pitfalls
- 4043 filler on 5083, which forms brittle magnesium silicide in the weld
- Hydrogen porosity from damp wire, hydrated oxide or oily plate
- Service above 65 °C (150 °F), which sensitizes 5083 and its welds to intergranular and stress corrosion cracking
- Designing to H116 yield across the weld; welded yield is closer to 165 MPa (24 ksi) than the 215 MPa (31 ksi) plate minimum
- Distortion of thin plate from high heat input and twice the thermal expansion of steel; sequence and fixture
- Joining 5083 to 6061 and assuming 5083 strength; the 6061 heat-affected zone sets the joint strength
Frequently asked questions
- What filler rod is used for 5083 aluminum?
- ER5183 is the standard. ER5356 is widely used with slightly lower weld strength, and ER5556 gives the highest. Avoid 4043 and 4047, which form brittle compounds with the magnesium in 5083.
- Does 5083 lose strength when welded?
- Only its strain hardening. The weld zone returns to the annealed strength, about 275 MPa (40 ksi) tensile, against a 305 MPa (44 ksi) minimum for 5083-H116. Heat-treatable alloys like 6061-T6 lose far more, dropping to about 165 MPa (24 ksi).
- Is 5083 good for boat building?
- Yes. 5083-H116 and H321 plate to ASTM B928 are the standard aluminum hull materials, welded with ER5183. They resist seawater well, including at the welds. Keep them out of sustained service above 65 °C (150 °F).
