Alu-Mg-Mn Alloy Sheets are roll-formed from AA3004 aluminium strip for use in standing seam roof and wall systems. The alloy contains manganese and magnesium for improved strength and corrosion resistance, making it suitable for large public buildings where long spans and low maintenance are required. SENBO carries out incoming material verification on alloy grade, tensile properties, and coating thickness before forming. The production team also checks rib geometry and panel width at regular intervals to keep the profiles within the specified tolerance.
AA3004 contains approximately 1.0% to 1.5% manganese, 0.8% to 1.3% magnesium, and small amounts of silicon, copper, and zinc. This formulation balances formability with structural strength. The Alu-Mg-Mn Alloy Sheet surface is coated before roll forming using a PVDF fluorocarbon system with a minimum resin content of 70%. The coating process is carried out on a continuous line and includes cleaning, chromate treatment, primer, and topcoat. The finished coating provides consistent colour and long-term weather resistance.
| Property | Value | Basis / Comment |
|---|---|---|
| Base alloy | AA3004 (AlMg1Mn1) | Mn 1.0–1.5%, Mg 0.8–1.3%, balance Al |
| Thickness | 0.7–1.2 mm | 0.6 mm possible for corrugated profiles |
| Common profiles | YX65-300, YX65-400, YX65-430, YX65-500 | Standing seam; other sections on request |
| Density | 2.73 g/cm³ | About one third of steel |
| Tensile strength | 240–285 MPa | H36/H46 temper |
| Yield strength | ≥190 MPa | Minimum |
| Elongation | ≥3% | At break |
| Thermal expansion coefficient | 0.000023 /°C | 20–100°C |
| Fire rating | A1 | Non-combustible |
| Service life | >50 years | Coating warranty 15–20 years |
| Relevant standards | GB 50345, GB 50207, EN 573-3 | Design and material references |
The density of aluminium is 2.73 g/cm³, while steel is 7.85 g/cm³. For the same panel area, the aluminium roof weighs about one third as much as a steel roof. This weight reduction lowers the load on purlins, columns, and foundations. The tensile strength of AA3004 in H36 temper reaches 240 to 285 MPa, which is adequate for standing seam profiles and for long panels that must resist wind uplift and thermal movement. Several airport and stadium projects have used this material specifically to reduce structural steel tonnage.
Aluminium forms a thin, dense oxide layer when exposed to air. This layer prevents further oxidation of the base metal. Independent measurements indicate an annual thickness loss of roughly 0.5 micrometres in normal atmospheric conditions. A 0.7 mm panel would still retain about 0.65 mm after 100 years of exposure. The PVDF coating adds an additional barrier against industrial pollutants and salt spray. These two mechanisms support the specified design life of more than 50 years.
Metal roofs expand and contract with temperature changes. The standing seam system uses sliding T-clips that allow each panel to move along the slope while remaining fixed to the purlins. This prevents buckling or fastener fatigue. Single panels can be produced in lengths up to 120 metres without end laps, which removes potential leak points and improves watertightness. At Xiamen Xiang'an Airport, individual panels reached 101 metres. High-altitude roll forming machines produced the panels on site at 48 metres above ground, which increased installation efficiency by more than 35%.
The roof system at Xiamen Xiang'an Airport underwent wind uplift testing in a laboratory. The test programme simulated severe typhoon conditions using static and dynamic pressure loading. Four rounds of validation confirmed that the system can withstand wind forces equivalent to a Category 17 super typhoon. The tests covered metal roof panels, purlins, gutters, and fasteners, not just the panel alone.
The system achieves a Class A1 fire rating. The metal surface can withstand sparks and flames without contributing to fire spread. For lightning protection, panels with a thickness of 0.7 mm or more may serve as air terminals according to GB 50057. This eliminates the need for separate lightning rods that would require roof penetrations. The standing seam profile itself provides a continuous conductive path when correctly connected.
AA3004 has higher manganese and magnesium content than AA3003, giving it better strength and corrosion resistance. For standing seam roofs, AA3004 is often preferred because it can handle higher wind loads and longer spans without adding thickness.
Yes, the same material and standing seam profile can be applied to wall cladding. The profile dimensions and clip design may differ, and wind load requirements for walls must be checked separately.
A slope of 5% is typical for standard details. Lower slopes down to about 1.5 degrees may be possible with continuous panels and careful sealing, but the project engineer should verify the design for the specific climate and rainfall intensity.
A vapour control layer is normally included on the warm side of the insulation to prevent condensation within the roof build-up. The exact layers depend on building use and climate. The roof system designer should specify the complete assembly.
Material certificates should confirm the alloy grade, temper, mechanical properties, and coating type. Dimensional checks during production cover panel width, rib height, and length. For large projects, samples can be tested for coating thickness and adhesion. On-site receiving should verify the panel count, profile, and surface condition before installation begins.
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