Technical Overview of Mill Finish Aluminum Coil, Sheet, and Foil
Mill finish aluminum refers to aluminum alloy products in their raw, untreated state directly following the hot rolling or cold rolling process, without any secondary surface finishing, mechanical polishing, or chemical conversion coating. It features a natural, lightly oxidized surface film with standard rolling oil traces and a characteristic metallic sheen. Operating under standards such as ASTM B209, EN 485, and GB/T 3880, mill finish aluminum serves as the primary substrate for subsequent coating processes—including Polyvinylidene Fluoride (PVDF) coating, Thermoset Powder Coating, and Anodizing—as well as structural applications where surface aesthetics are secondary to mechanical strength, formability, and thermal conductivity.
Technical Specifications: Mill Finish Aluminum Matrix
The selection of aluminum alloy grade, temper, and mechanical properties dictates the material’s suitability for subsequent coil coating or direct structural integration.
| Technical Parameter | 1000 Series (e.g., 1050 / 1100) | 3000 Series (e.g., 3003 / 3105) | 5000 Series (e.g., 5052 / 5083) |
| Alloy Composition Focus | ≥ 99.0% Pure Aluminum | Aluminum-Manganese (1.0%～1.5%) | Aluminum-Magnesium (2.2%～4.9%) |
| Typical Temper States | O, H14, H24 | O, H14, H24, H18 | O, H32, H34, H111 |
| Tensile Strength (MPa) | 75 – 145 | 140 – 200 | 210 – 305 |
| Yield Strength (MPa) | 35 – 115 | 115 – 180 | 110 – 240 |
| Elongation (%) | 5 – 35 | 3 – 25 | 7 – 25 |
| Corrosion Resistance | High (Atmospheric) | Very High (Atmospheric/Chemical) | Exceptional (Marine/Salt Spray) |
| Substrate Compatibility | Decorative trim, foil insulation | Roof roofing sheets, color-coated coil base | Marine hulls, pressure vessels, high-stress architectural panels |
| Applicable Standards | ASTM B209, EN 485-2 | ASTM B209, EN 485-2, GB/T 3880 | ASTM B209, EN 485-2, ISO 6361 |
Structural Breakdown of Mill Finish Form Factors
Mill Finish Aluminum Coil
Mill finish aluminum coil is manufactured through continuous rolling processes and supplied in tightly wound cylindrical reels. It acts as the primary feed material for continuous pre-painted aluminum coil lines (CCL), roll-forming equipment, and continuous stamping operations. Coils are categorized by inner diameter (typically 508 mm or 610 mm) and coil weight capacities (3–10 metric tons).
Mill Finish Aluminum Sheet
Mill finish aluminum sheets are flat-rolled products cut to specific lengths directly from coils or produced via plate mills. Ranging typically from 0.5 mm～6.0 mm in thickness, these sheets are widely used in structural cladding, transportation panels, and electrical enclosures where direct fabrication (bending, laser cutting, welding) is performed prior to post-painting or powder coating.
Mill Finish Aluminum Foil
Defined as gauge thickness below 0.2 mm (200 μm), mill finish aluminum foil exhibits high barrier performance against moisture, oxygen, and light. It undergoes double-roll cold reduction to achieve ultra-thin gauges down to 0.006 mm. It serves as a core substrate for thermal insulation laminates, HVAC fin stock, flexible packaging, and transformer winding applications.