Fan blades for industrial ceiling fans, high-volume low-speed units and axial ventilation equipment must combine low rotating mass with enough stiffness to hold their pitch at speed. 5052 aluminum plate is the established choice for this duty: a magnesium addition of 2.2–2.8% lifts strength well above 1100 or 3003 sheet while keeping the material highly formable, weldable and resistant to atmospheric corrosion. Blades are normally cut, drilled and bent from 1.5–3 mm plate supplied in the H12, H22 or H32 tempers.
Why 5052 Aluminum Plate Suits Fan Blade Manufacturing
Light weight with useful strength - a density of about 2.68 g/cm³ keeps blade inertia and motor load low, while a tensile strength of 210–280 MPa in H12 supports the aerodynamic and centrifugal loads developed at operating speed.
Corrosion resistance - no copper is added to the alloy, so the surface remains stable in humid, coastal and mildly chemical atmospheres without painting or plating.
Formability - the semi-hard tempers bend to tight radii without cracking, which is essential for single-piece airfoil profiles and rolled leading edges.
Thermal conductivity and fatigue life - heat generated near the hub is spread quickly through the blade, and the alloy tolerates the repeated reversed bending stress imposed by every revolution.
H12, H22 and H32: Which Temper to Choose
All three tempers are strain hardened, but they differ in how that hardening is finished. H12 receives a controlled amount of cold work and is left at that level. H22 is strain hardened and then partially annealed, trading a little strength for extra ductility. H32 is strain hardened and stabilised, which gives a more stable structure during long service and at slightly elevated hub temperatures. The corresponding temper designations follow ANSI H35.1 and EN 515, while chemical composition and mechanical property limits are covered by ASTM B209 and EN 485-2.
| Temper | Tensile strength | Minimum yield strength | Typical blade use |
|---|---|---|---|
| H12 | 210–280 MPa | 180 MPa | Stiff blades with moderate bend severity |
| H22 | 210–260 MPa | 130 MPa | Deep-drawn and compound-curved blades |
| H32 | 210–260 MPa | 130 MPa | Stable pitch in warm hubs and long duty cycles |
Standard Specification Range
| Item | Range |
|---|---|
| Alloy | 5052 |
| Temper | H12, H22, H32; H38 and H112 also available |
| Thickness | 1.5–3.0 mm |
| Width | 1000–2000 mm |
| Length | 3000–6000 mm |
| Surface finish | Single-sided or double-sided polished, mill finish, anodised, colour coated |
| Colour | Silver or to project requirement |
| Packing | Strapped bundles on wooden pallets |
Mechanical Properties by Temper and Thickness
| Temper | Thickness | Tensile strength | Proof strength | Elongation |
|---|---|---|---|---|
| H12 | 0.50–1.50 mm | 210–280 MPa | 180 MPa | 5% |
| H12 | 1.50–3.00 mm | 210–280 MPa | 180 MPa | 5% |
| H12 | 3.00–6.00 mm | 210–280 MPa | 180 MPa | 8% |
| H22 / H32 | 0.50–1.50 mm | 210–260 MPa | 130 MPa | 5% |
| H22 / H32 | 1.50–3.00 mm | 210–260 MPa | 130 MPa | 7% |
| H22 / H32 | 3.00–6.00 mm | 210–260 MPa | 130 MPa | 10% |
Forming, Surface Treatment and Inspection
Blade blanks are usually laser cut or blanked, the root holes are punched or drilled, and the airfoil is produced by press bending or roll forming. Because H22 and H32 retain 7–10% elongation in the 1.5–3 mm range, they tolerate drawing and stretch forming better than H12, which is preferred where flatness and stiffness dominate over bend severity. The recommended minimum bend radius for 5052 in the H32 temper is approximately 1.5 times the sheet thickness across the rolling direction and around 1.0 times with the bend line parallel to rolling.
Surface treatment options include chemical conversion coating, anodising and polyester or PVDF colour coating. Anodising raises wear resistance at the leading edge, where airborne dust abrasion is most severe, and improves the aesthetic finish of exposed blades. Every lot should be released against a mill certificate showing composition, temper, tensile strength, elongation and flatness, and thickness should be verified with a calibrated gauge at multiple points across each plate, since blade balance depends directly on consistent mass distribution.
Frequently Asked Questions
Q: Which temper is best for a bent airfoil blade?
H22 or H32 is normally chosen because the partially annealed or stabilised condition provides 7–10% elongation, allowing the airfoil to be formed without cracking while keeping a tensile strength of 210–260 MPa.
Q: Does 5052 plate need painting for outdoor fans?
No, the alloy resists atmospheric and coastal corrosion without coating. A coating or anodised layer is added mainly for appearance, abrasion resistance or colour matching.
Q: What thickness is used for 2 to 3 metre fan blades?
Cold-bent industrial blades commonly use 1.5–3.0 mm thickness, with the heavier end of the range selected for larger diameters and higher rotational speeds.
Q: Is 5052 suitable for welded blade hubs?
Yes. 5052 is readily joined by gas tungsten arc welding and by resistance spot welding, and it is more crack resistant than high-magnesium grades above 3.5% Mg.
Q: What tolerance can be held on thickness and width?
Thickness and width tolerances are agreed against ASTM B209 or EN 485-4 limits; typical commercial tolerances are a few hundredths of a millimetre on thickness and a few millimetres on width.
Q: How is the material supplied to protect the surface?
Plates are supplied strapped in bundles on wooden pallets, with interleaved protective film or paper available so that the polished or coated face arrives without handling marks.
