One Alloy, Two Tempers
5052 H32 and 5052 H34 are the same material chemically: an aluminum-magnesium alloy with 2.2-2.8% magnesium and 0.15-0.35% chromium, in the same 5xxx family, both non-heat-treatable. What differs is the amount of cold reduction applied after the final anneal. In the H3x series the first digit means the product was strain hardened and then stabilized, and the second digit records the degree of cold work: 2 for quarter hard (H32) and 4 for half hard (H34). Stabilization is a low-temperature treatment that removes the age-softening tendency of magnesium-bearing alloys and gives the sheet a stable strength level at service temperature.
Typical Mechanical Properties
| Property (room temperature, typical) | 5052 H32 | 5052 H34 |
|---|---|---|
| Tensile strength | about 228 MPa | about 260 MPa |
| 0.2% proof stress | about 193 MPa | about 215 MPa |
| Elongation in 50 mm | about 12-18% | about 8-12% |
| Minimum bend radius, 90 degrees | about 1.0 times thickness | about 1.5 times thickness |
| Density | 2.68 g/cm3 | 2.68 g/cm3 |
ASTM B209 / B209M and EN 485-2 set minimum property values for each temper and thickness band, and the minima for H34 sit one step above those for H32. Both tempers share the same corrosion resistance, weldability and density, so the choice between them is made on strength against formability rather than on any difference in alloy behaviour.
Forming, Springback and Bendability
The higher cold work in H34 buys strength at the cost of ductility. In practice H34 needs a larger bend radius, shows more springback after bending so the tool has to over-bend, and is more prone to edge cracking when blanking or shearing thick sheet. H32 is the friendlier forming temper and is the usual choice for panels that will be rolled, stamped or press-braked into shape. Where a tight radius has to be combined with H34 strength, the part is often formed in the softer temper and used without further hardening, or the bend line is arranged transverse to the rolling direction to reduce cracking risk.
Welding and Heat Effects
Both tempers weld readily by MIG and TIG with 5356 or 5556 filler. Welding removes the cold work in the heat-affected zone, so local strength falls toward annealed values regardless of the temper supplied, and the difference between H32 and H34 narrows sharply next to a weld. For a welded assembly, therefore, paying for H34 in the parent metal brings little benefit along the joint itself; H34 pays off in unwelded areas that need stiffness or dent resistance. Residual stress and distortion are slightly greater in H34 because it starts with more stored strain energy, which is another reason to prefer H32 for large welded panels.
Choosing Between H32 and H34
Specify H32 for general sheet-metal fabrication, curved panels, formed enclosures, fuel and hydraulic tanks, marine trim, trailer and truck body skins, and any part where forming dominates the production route. Specify H34 where greater stiffness or strength is needed without added thickness: floor plates and tread panels, heavy-duty fascia, shelving and racking, machine guards and guards subject to impact, and structural brackets that will be bolted rather than welded. If both formability and strength are needed, consider 5052 H32 with a slightly greater thickness, or move to a higher-magnesium alloy such as 5083 in a marine temper where the extra strength is justified.
Frequently Asked Questions
Q: Is H34 stronger than H32?
A: Yes. H34 is half hard against quarter hard for H32, so it carries a higher minimum tensile and yield strength, with a correspondingly lower elongation.
Q: Can H34 be bent to a tight radius?
A: Only with care. It needs roughly 1.5 times the thickness as a minimum 90 degree bend radius, against about one thickness for H32, and may crack if bent across the rolling direction at a tighter radius.
Q: Do the two tempers corrode differently?
A: No. Chemistry and therefore corrosion behaviour are the same, so temper selection in a corrosive environment is driven by strength and stress level rather than by corrosion resistance.
Q: Which temper welds better?
A: Both weld equally well with 5356 or 5556 filler, but H32 distorts less and is easier to bring back into tolerance after welding large panels.
Q: What does the number after H3 mean?
A: It records the degree of cold work: 2 is quarter hard, 4 is half hard, 6 is three-quarter hard and 8 is full hard. The 3 shows the product was strain hardened and then stabilized.
Q: Can H32 be upgraded to H34 by cold rolling?
A: Not reliably at the user's site. Temper is set by controlled mill processing to a standard minimum, so the sheet should be ordered in the temper required for the finished part.