Aluminum Roll Forming: Alloys, Profiles & Springback Guide | ZTRFM Wiki

1. Definition and Scope

Aluminum roll forming shapes aluminum alloy strip coil into structural and architectural profiles using the same progressive roller bending process as steel roll forming. Aluminum offers density approximately one-third of steel (2.7 g/cm³ vs 7.85 g/cm³), natural corrosion resistance through oxide film, and high thermal conductivity. Roll forming complements aluminum extrusion for profiles where continuous long lengths, thin gauge, or integrated punching/cutting justify coil-based production.

Aluminum strip for roll forming is supplied per ASTM B209, EN 485, or EN 573 in alloys from the 1xxx (pure), 3xxx (Al-Mn), 5xxx (Al-Mg), and 6xxx (Al-Mg-Si) series. Extrusion dominates aluminum profile markets for complex hollow shapes; roll forming competes on open sections (C, Z, U, hat), thin-gauge panels, and applications requiring steel-roll-forming-like production economics at lower weight.

Key differences from steel roll forming include higher springback (due to lower elastic modulus E ≈ 70 GPa vs 210 GPa), galling tendency on unprotected tool steel, lower forming force per unit yield strength, and sensitivity to surface scratching. Successful aluminum roll forming requires alloy and temper selection matched to bend severity, polished or coated tooling, and often higher over-bend compensation than equivalent steel profiles.

2. Aluminum Alloy Selection

Alloy choice depends on strength requirement, corrosion environment, weldability, and formability. Non-heat-treatable 3xxx and 5xxx alloys work-harden during forming; heat-treatable 6xxx alloys derive strength from temper (T4, T6) and may age-harden after forming if left in W or T4 condition.

2.1 Common Roll Forming Alloys

2.2 Aluminum vs Steel Roll Forming Comparison

3. Temper and Mechanical Properties

Aluminum temper designation (H for strain-hardened, T for heat-treated) defines mechanical properties at delivery. Roll forming generally uses O (annealed), H12–H34 (strain-hardened), or T4/T5/T6 tempers depending on whether post-form age hardening is desired.

3.1 Temper Selection for Roll Forming

6063-T5 and 6063-T6 are widely used for solar module frames roll formed from coil. T5 offers better formability during roll forming; T6 provides higher final strength if bend radii are generous. Some producers roll form in T4 temper and allow natural aging in storage before shipment to achieve T4-to-T6 strength without forming T6 at full yield stress.

4. Springback and Low Modulus Effects

Aluminum springback is approximately three times steel springback for the same yield stress and geometry because elastic recovery strain equals stress divided by modulus (σ/E), and E for aluminum is one-third that of steel. A 90° bend in 6063-T5 may require 5–10° over-bend where mild steel requires 2–3°.

4.1 Springback Compensation by Alloy-Temper

4.2 Springback Reduction Techniques

5. Tooling and Surface Protection

Aluminum adheres to unprotected tool steel under pressure (galling), similar to stainless. Roll surfaces require polishing (Ra 0.2–0.4 μm), hard chrome plating, or nylon/bronze wraps on side rolls. Dedicated aluminum tooling avoids iron contamination that would cause galvanic or cosmetic issues when aluminum contacts steel in assembly.

5.1 Tooling Recommendations

Pre-painted or anodized aluminum coil requires contact surfaces free of grit and steel particles. Film-coated stock (PE protective film) is often roll formed with film on exterior surface; roll contour must not shear the film at bend tangent points.

6. Minimum Bend Radius

Minimum inside bend radius for aluminum depends on alloy, temper, and sheet thickness per Aluminum Association data and ASTM B209 supplementary tables. Exceeding limits causes orange peel, grain separation, or cracking on outer bend surface.

6.1 Minimum Inside Bend Radius (Transverse)

7. Process Parameters

Aluminum roll forming lines typically run at moderate speed because high speed generates heat at roll contact that can soften the strip locally and alter springback behavior mid-coil. Uncoiler tension must be lower than steel to avoid permanent elongation of soft tempers.

Aluminum roll formed sections join by MIG welding, riveting, clinching, or bolted connectors. Anodizing and powder coating are applied after forming; bend radius must allow coating coverage without cracking on outer bend. For architectural anodized profiles, forming lubricant must be silicone-free to avoid staining during anodizing.

8. Applications

Designers choosing roll formed aluminum over extrusion should compare tooling amortization (roll sets vs extrusion die), minimum economic volume, section complexity (extrusion wins on hollow and multi-void), and tolerance requirements. Roll forming suits open sections with continuous holes (punched inline) and lengths exceeding extrusion press capacity (typically < 25–30 m extrusion length vs unlimited coil).

8.1 Environmental and Lifecycle Considerations

Aluminum roll formed profiles are fully recyclable without property loss. Coil-based production generates less trim scrap than nested brake-formed blanks when developed width is optimized. Combined with lower transport energy due to reduced mass, aluminum roll forming appears in solar and electric vehicle programs targeting lifecycle carbon reduction alongside structural function.

Related topics

• Springback in Roll Forming
• Material Hardness and Thickness Limits in Roll Forming
• Zinc-Aluminum-Magnesium (Zn-Al-Mg) Coated Steel