Failure modes
Eight things that go wrong with aluminium — and what to write into the order
Search for a supplier and you get a supplier. Search for the defect you are actually fighting and you get an answer. These eight pages are written for the second kind of search: what the failure is, why it happens, how it is measured, and the sentence to put in your RFQ so it is enforceable afterwards.
Index
The eight failure modes
Each page carries the same four parts: what it is, why it happens, how it is measured, and what to specify. None of them promise the defect will never occur.
Pinholes in Aluminium Foil
Why aluminium foil gets pinholes: melt cleanliness, rolling oil filtration and thin gauge. How pinhole count is measured under ASTM B479 and GB/T 3198.
2Camber and Wavy Edge in Sheet & Coil
Why aluminium sheet and coil show camber or wavy edge, how it is measured under EN 485 and ASTM B209, and what to specify to keep it off your automatic line.
3Weld Cracking & Sensitisation in 5xxx Plate
Why 5083 aluminium plate cracks or corrodes in service: sensitisation above 65°C, H116 vs H32 temper, filler wire choice, and the ASTM G67 test to specify.
4Anodising Colour Variation
Why anodised aluminium varies in colour between batches: alloy drift, extrusion parameters and bath control. How film thickness and colour are specified.
5Thickness Out of Tolerance
Why aluminium arrives thinner than specified: minus-tolerance rolling and edge drop. How to write thickness tolerance into an order under ASTM B209.
6Telescoped or Loose Coil
Why aluminium coils telescope or collapse: winding tension, core strength and transport restraint. What to specify for coil ID, weight, core type and packing.
7Burr on Slit Aluminium Strip
Why slit aluminium strip has edge burr: knife clearance, blade wear and temper. How burr height is measured and what to specify for transformer and fin stock.
8Water Staining & White Rust in Transit
Why aluminium arrives with white stains: condensation inside the packing and undersized desiccant. Packing specification and claim window.
Why we publish this
Defects are a specification problem before they are a quality problem
Most aluminium disputes are not about bad metal. They are about an order that never said what "acceptable" meant. A thickness written as "1.0 mm" is not a requirement; a thickness written as "1.0 mm to ASTM B209 table" is. A finish written as "anodised" is not a requirement; "AA15, single heat, delta E against signed master sample" is.
We would rather tell you what to write into the RFQ than argue about it after the container lands. It is also the cheapest quality control either of us will ever pay for.
The second reason is that a supplier who explains a failure mode is easier to evaluate than one who only lists products. If you are comparing us against a mill that has never mentioned pinhole counts, that difference is information.