Specify the coated product
Galvalume steel coil carries the conventional 55% aluminum-zinc metallic coating on a steel substrate. The delivery specification combines substrate grade, coating designation, dimensions and surface treatment. This page focuses on those fields; the Galvalume explanation explains chemistry and terminology.
AZM150 is a coating field
ASTM A792/A792M-25a covers the 55% aluminum-zinc family with Type 1 (Al-Zn-Si) and Type 2 (Al-Zn-Mg-Si). Specify the coating type; a reference to A792 alone does not prove conventional Galvalume chemistry or a licensed trademark product. AZM150 denotes a 150 g/m² minimum triple-spot average total coating mass on both faces under the ASTM metric system. Other test minima remain part of the standard. The designation does not identify steel strength.
The current ASTM A792/A792M-25a public scope , checked active on 18 September 2026, confirms the two types. BIEC is the source for Galvalume trademark and licensing identity. Retain the contract edition; a public scope does not replace full grade/coating tables. Under EN 10346, AZ is the Al-Zn coating suffix; under ASTM, AZ and AZM distinguish inch-pound and SI designations. Always retain the system and units when transcribing a certificate.
Base thickness, width and surface treatment
Specify BMT if the requirement concerns the steel substrate. Total coated thickness adds metallic layers on both sides. For coil handling, give width, edges, ID, maximum OD and net mass; for roofing, separate flat feed width from the panel’s installed cover.
Surface options include a metallic finish and producer-specific clear resin treatments intended to improve handling and reduce marking. A clear resin layer is different from an exterior pigmented topcoat. When painting follows, agree the exact surface treatment with the coating line. The PPGL layer diagram shows the additional paint system.
For the ASTM route, A924/A924M-26 gives general requirements and a base-steel-plus-coating thickness basis. A required BMT must be explicitly reconciled with that basis. Record passivation, oil or named resin treatment separately, including paint-line compatibility; do not treat “resin coated” as a complete surface specification.
A product-description reading example
| Field | Example or required decision |
|---|---|
| Product standard | ASTM A792/A792M, contract edition and coating Type 1 or Type 2 recorded; state licensed product identity if required. |
| Substrate | Choose the forming or structural designation required by the panel or component. |
| Metallic coating | AZM150; retain total-both-side and sampling requirements. |
| Dimensions | Example: 0.50 mm required BMT × 1,200 mm; separately reconcile total coated thickness and its standard tolerance basis, trimmed/mill edge and width tolerance. |
| Surface | Name the supplied resin/passivation/oil condition and painting compatibility. |
| Coil / inspection | Specify bore ID, maximum OD and net coil mass for the receiving line, packing, heat/coil identity, ordered inspection certificate and coating/grade/dimension test results. |
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The example dimensions describe a worksheet, not an available product range. A roofing-system design supplies the final grade, thickness and profile requirements. The coating converter can convert mass units, while its zinc-designation table remains specific to galvanized sheet.
Forming and building applications
Al-Zn sheet is widely used in roof and wall panels and as the metallic substrate for PPGL. Roll-forming tooling, lubrication and surface treatment need to control marking as well as panel shape. Tight bends and drawn parts require evidence for the selected grade/coating combination.
The GalvInfo Al-Zn note, revision 1.2 (2017) discusses building cladding and clear-resin treatments. For severe drawing, compare the coating adhesion demands against the galvanized alternative .
For building use, obtain the panel supplier’s exposure and contact-material restrictions, fastening details and underside-condensation guidance. Bare Al-Zn has specific limitations around alkaline concrete contact and intensive animal-confinement environments; those selection differences are covered in the comparison .