Can 5052 aluminum be welded?
Yes, easily. 5052 is one of the best welding aluminum alloys: TIG or MIG with ER5356 filler gives a strong, crack-free joint, and the only strength loss is the H32 work-hardening, which drops the weld zone to the O temper.
5052 is a magnesium-strengthened (5xxx) alloy that gets its strength from cold work, not heat treatment, and that is exactly why it welds so well. There is no precipitation structure for the arc to over-age, hot-cracking resistance is excellent, and the weld metal made with a 5xxx filler is nearly as strong as the parent. The heat-affected zone of an H32 sheet does anneal back to the O condition, so the weld region falls from about 230 MPa (33 ksi) tensile to roughly 195 MPa (28 ksi), a loss of 15-20% rather than the 35-45% that welded 6061-T6 suffers. Designers who build tanks, boat hulls, truck bodies, enclosures and fuel tanks in 5052 usually do not have to think about the weld as the weak point.
ER5356 is the standard filler and matches the parent alloy in colour after anodizing and in corrosion resistance; ER5556 or ER5183 are used where higher weld strength is wanted, and ER5654 in some chemical service. ER4043 will weld 5052 but gives a weaker, less ductile joint that turns grey under anodize, and its silicon-magnesium combination in the weld metal can form brittle Mg2Si; use it only if the assembly also contains 6xxx or cast parts that need it. All the aluminum hygiene rules apply: degrease, stainless-brush the oxide off immediately before welding, use clean argon, and keep the interpass temperature moderate to limit the annealed zone. Magnesium alloys spatter a little more than 6061 under MIG and the arc is slightly more sensitive to contamination, but 5052 is forgiving compared with any heat-treatable alloy.
Two points for the drawing. 5052 is only about half as strong as 6061-T6 in the parent metal, so a welded 5052 structure and a welded 6061 structure end up with similar joint strengths; choose 5052 when the part is formed and welded, 6061 when it is machined and bolted. And 5052 in the H32 and H34 tempers is stable at any normal service temperature, unlike 5083 and 5456 with more than 3% magnesium, which sensitise to intergranular corrosion above about 65 °C (150 °F); 5052 at 2.5% Mg does not have that problem in practice.
Welding for 5052 parts: where to send them
What to specify
- Process and filler: GTAW or GMAW with ER5356 per AWS A5.10 (ER5183 or ER5556 for higher weld strength)
- Temper as purchased (5052-H32 is the usual sheet temper) and a note that the weld zone is designed at O-temper strength
- Weld symbols and sizes per AWS A2.4; continuous or intermittent, and which welds are leak-tight
- Acceptance criteria per AWS D1.2 (structural) or the pressure or tank code that applies; leak or dye-penetrant test if it holds fluid
- Distortion control on thin sheet: fixturing, back-step or skip sequence, and any flatness requirement after welding
- Finish after welding: as-welded, ground flush, and whether the assembly is anodized (5356 matches) or painted
Pitfalls
- ER4043 on 5052: a weaker, grey-anodizing weld with Mg2Si in the fusion zone; specify 5356 unless there is a reason not to
- Expecting H32 strength across the weld: the heat-affected zone anneals to O, about 15-20% weaker, and cannot be re-hardened
- Warping of thin sheet from aluminum's high expansion and conductivity; clamp, skip-weld, and use the smallest bead that meets the size
- Porosity from oil, moisture or old oxide; brush the joint right before welding, and keep the argon dry
- Burn-through on sheet under 1.5 mm (0.060"): use pulsed MIG or AC TIG with a small tungsten and a backing bar
- Confusing 5052 with 5083 or 5456 for hot service: the higher-magnesium alloys sensitise above about 65 °C, 5052 does not
Frequently asked questions
- What filler should I use to weld 5052?
- ER5356 for nearly everything: it matches strength, colour and corrosion behaviour. ER5183 or ER5556 where the weld must be stronger. Avoid ER4043 unless the joint also includes a 6xxx alloy or a casting that needs it.
- Is 5052 easier to weld than 6061?
- Yes. It has no heat-treated temper to lose, a smaller strength drop at the weld, better hot-cracking resistance and fewer filler restrictions. It is the preferred alloy for welded sheet-metal work, tanks and marine parts.
- How much strength does 5052 lose when welded?
- About 15-20% at the weld zone on H32 sheet, from roughly 230 MPa (33 ksi) tensile to the O-temper level of about 195 MPa (28 ksi). The loss is cold work annealing out, so it applies to H34 and H36 as well and cannot be recovered by heat treatment.
