Galvalume steel, defined as 55% aluminum, 43.4% zinc, and 1.6% silicon alloy-coated steel, is governed by two dominant global standards: ASTM A792 (US) and EN 10346 (Europe). While both specify hot-dip Al-Zn coated steel for corrosion and heat resistance, they differ in scope, grading, coating rules, and testing-critical for cross-border project compliance, cost control, and performance predictability.
What Is Galvalume Steel?
Galvalume (Al-Zn alloy-coated steel) is a continuous hot-dip coated flat product with a 55% Al-Zn-Si coating, offering 2–6× better corrosion resistance than galvanized steel, heat resistance up to 450°C, and 70%+ solar reflectivity. It is the preferred material for roofing, siding, HVAC, and industrial panels worldwide. ASTM A792 and EN 10346 are the primary standards ensuring consistent quality across regions, with ASTM A792 dominating North America and EN 10346 leading Europe and global trade.
ASTM A792: US Standard for 55% Al-Zn Coated Steel
ASTM A792/A792M-25 (2025) is the latest US standard specifying 55% aluminum-zinc alloy-coated steel sheets/coils for corrosion and heat resistance applicationsASTM International. It focuses on product-specific requirements for North American construction, automotive, and industrial markets.
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Scope & Key Specifications
Coating Composition: Fixed at 55% Al, 43.4% Zn, 1.6% Si; two types: Type 1 (Al-Zn-Si) and Type 2 (Al-Zn-Mg-Si)ASTM International.
Thickness: 0.2–1.2 mm; Width: 800–1,250 mm.
Grading System:
Base Steel: CS (Commercial), FS (Forming), DS (Drawing), DDS (Deep Drawing), SS (Structural)ASTM International.
Structural Grades: Grade 33 (230 MPa), 37 (255 MPa), 40 (275 MPa), 50 (340 MPa), 80 (550 MPa).
Coating Weight: Designated as AZ50–AZ180 (g/m²); e.g., AZ150 = 150 g/m² total coating mass.
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Core Advantages & Applications
Superior Heat Resistance: Withstands up to 450°C (short-term) without oxidation, ideal for high-temperature environments.
Long Service Life: >40 years in rural (C2) environments; 25 years without perforation in industrial (C4) zones.
Key Applications: Metal roofing, wall siding, HVAC ducts, automotive parts, and agricultural equipment.
EN 10346: European Standard for Continuous Hot-Dip Coated Steel
EN 10346:2015 is the European standard specifying continuously hot-dip coated flat products (including Al-Zn, Zn, ZF, ZA, AS, ZM coatings) for cold forming, construction, and high-strength applications. It has a broader scope than ASTM A792, covering multiple coating types and steel grades.
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Scope & Key Specifications
Coating Composition: Al-Zn (AZ) coating matches ASTM A792: 55% Al, 43.4% Zn, 1.6% Si.
Thickness: 0.20–3.0 mm (up to 6.5 mm by agreement); Width: all widths (≥600 mm sheets, <600 mm cut lengths).
Grading System:
Base Steel: DX51D, DX52D, DX53D, DX54D (cold forming); S220GD–S550GD (structural).
Coating Designation: AZ100–AZ200 (g/m²); e.g., AZ150 = 150 g/m².
Compliance: Mandatory CE marking for EU market access.
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Core Advantages & Applications
Versatility: Covers more steel grades and thicknesses, suitable for diverse European construction and industrial needs.
Enhanced Formability: DX-series grades offer excellent ductility for complex bending, stamping, and profiling.
Key Applications: Building envelopes, solar supports, refrigeration panels, marine architecture, and prefabricated components.
ASTM A792 vs. EN 10346: Critical Differences
1. Scope & Coverage
ASTM A792: Exclusive to 55% Al-Zn coated steel (sheets/coils); narrow focus on product qualityASTM International.
EN 10346: Broad scope covering Zn, ZF, ZA, AZ, AS, ZM coatings; includes cold-forming, construction, and high-strength steels.
2. Grading & Nomenclature
| Aspect | ASTM A792 | EN 10346 |
|---|---|---|
| Base Steel | CS, FS, DS, DDS, SS | DX51D–DX54D (cold forming); S220GD–S550GD (structural) |
| Structural Grades | Grade 33 (230 MPa) to 80 (550 MPa) | S220GD (220 MPa) to S550GD (550 MPa) |
| Coating Label | AZ50–AZ180 | AZ100–AZ200 |
3. Coating & Dimensional Rules
ASTM A792: Thickness 0.2–1.2 mm; width 800–1,250 mm; strict coating weight tolerance (±10%).
EN 10346: Thickness 0.20–3.0 mm (up to 6.5 mm by agreement); all widths; more flexible tolerance for special orders.
4. Testing & Compliance
ASTM A792: Requires triple-spot coating weight tests, bend tests, and salt spray resistance (1,200+ hours)ASTM International.
EN 10346: Mandatory CE marking; tests per EN 13523 series (coating adhesion, corrosion resistance, formability).
5. Regional Preferences & Performance
ASTM A792: Preferred in North America, Australia, and parts of Asia; optimized for high heat resistance (450°C).
EN 10346: Dominant in Europe, Middle East, and Africa; emphasizes cold formability for complex designs.
Frequently Asked Questions (FAQ)
1. What is the main difference between ASTM A792 and EN 10346?
ASTM A792 is US-specific, focusing exclusively on 55% Al-Zn coated steel with fixed thickness/width rangesASTM International. EN 10346 is European, covering multiple coating types (Zn, ZF, AZ, etc.) and broader thickness/width options, with mandatory CE marking.
2. Are ASTM A792 and EN 10346 galvalume interchangeable?
Yes, for most applications-both use 55% Al-Zn-Si coating with identical corrosion/heat resistance. However, EN 10346 offers more grades (e.g., DX51D, S550GD) and thicknesses (up to 3.0 mm). ASTM A792 is preferred for North American projects; EN 10346 for EU/global trade.
3. What coating weight options are available for each standard?
ASTM A792: AZ50, AZ70, AZ100, AZ120, AZ150, AZ180 (g/m²).
EN 10346: AZ100, AZ120, AZ150, AZ180, AZ200 (g/m²); AZ150 is the most common for both.
4. Which standard is better for roofing applications?
Both work, but ASTM A792 is more widely used for roofing in North America due to its superior heat resistance (450°C) and long-term durability (>40 years in rural areas). EN 10346 is preferred for European roofing, offering better formability for complex profiles.
5. What mechanical properties do ASTM A792/EN 10346 galvalume have?
ASTM A792: Yield strength 230–550 MPa; tensile strength 310–650 MPa; elongation 18–20%.
EN 10346: DX-series (cold forming): yield 140–260 MPa, tensile 270–420 MPa; S-series (structural): yield 220–550 MPa.
6. How to verify compliance with ASTM A792 or EN 10346?
ASTM A792: Check for ASTM A792/A792M-25 marking; verify coating composition (55% Al, 43.4% Zn, 1.6% Si) and weight via SGS/BV test reportsASTM International.
EN 10346: Look for CE marking and EN 10346:2015 certificate; confirm grade (DX51D/S550GD) and coating weight (AZ150) per EN 13523 tests.
7. Can GNEE STEEL provide customized galvalume per both standards?
Yes. GNEE STEEL offers custom thickness (0.2–3.0 mm), width (800–1,500 mm), and coating weight (AZ100–AZ200) for both ASTM A792 and EN 10346. We also provide surface finishes (smooth, orange peel, crystalline) and cut-to-length services.
8. What is the typical lead time and MOQ for GNEE STEEL galvalume?
Lead Time: 20 days for standard sizes; 25–30 days for customized specifications.
MOQ: 18 tons (one coil); small trial orders (≥5 tons) available upon request.
Delivery: Global shipping to North America, Europe, Southeast Asia, and the Middle East; door-to-door delivery available.
