A3004 H26 0.4mm thickness color coated aluminum coil

12/10 2025

A3004 H26 0.4mm Color Coated Aluminum Coil: A Thin Material with “Thick” Technical Logic

When engineers choose 0.4mm color coated aluminum coil, they’re not just saving weight; they’re making a point about precision, forming behavior, and lifecycle performance. Among the common alloys, A3004 H26 color coated aluminum coil at 0.4mm thickness occupies a very strategic niche: thin enough for lightweight applications, yet strong and stable enough for demanding façade, roofing, ceiling, shutter, and interior panel systems.

1. What Makes A3004 Different in the 3xxx Family?

In the 3xxx series, the base concept is:
Al-Mn alloy = corrosion resistance + moderate strength + good formability.

A3003 and A3004 are close “relatives,” but A3004 is upgraded:

• A3003: Al–Mn only
• A3004: Al–Mn–Mg
  • Addition of Mg significantly increases strength without destroying formability.

For a 0.4mm color coated coil, this is decisive:

• At small thickness, panel stiffness depends not just on geometry, but also yield strength.
• A3004 keeps bending behavior stable, even with thin gauges, especially in tempers like H26 where moderate hardening is introduced.

From the design engineer’s perspective:
A3004 is the “thin, strong, still workable” solution in the 3xxx coated sheet space.

2. The Hidden Role of H26 Temper in 0.4mm Coils

Temper H26 is often misunderstood as just “hard.” More precisely:

• H2x series: Strain hardened, then partially annealed.
• H26:
  • Significant strain hardening + controlled partial anneal
  • Target: high strength, moderate ductility
  • Higher strength than H24, less ductility than H24, but better resistance to denting and buckling.

Why is H26 especially logical for 0.4mm?

• Surface impact: Thin panels are easily dented; H26 provides higher yield strength, reducing “oil-canning” and visible deformations beneath the coating.
• Edge handling: In slitting and roll-forming, H26 resists edge damage and “tearing” better than very soft tempers.
• Profile stability: For roofing tiles, ceilings, or cassette systems, H26 supports shape retention after forming and service loading.

Engineers discovering coil defects downstream often misattribute problems to “the coating” or “installers”; in practice, improper temper choice at a given thickness can be the root cause.
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3. Typical Chemical Composition of A3004 Alloy

The chemical design of A3004 is what allows the temper and forming processes to be tuned without losing corrosion performance.

Table 1 – Typical Chemical Composition of A3004 (wt.%)

Functional interpretation:

• Mn (1.0–1.5%)

  • Solid solution strengthening and grain control.
  • Improves corrosion resistance in many atmospheric and building environments.

• Mg (0.8–1.3%)

  • Adds a second strengthening mechanism (Al–Mg).
  • Increases yield and tensile strength, crucial for 0.4mm sheet stiffness.

• Low Cu, Zn, Fe

  • Limits pitting and galvanic sites.
  • Keeps general and intergranular corrosion under control under coatings, especially at cut edges.

• Si, Ti (trace)

  • Grain refining and controlled cast structure.
  • Ensures consistent mechanical and surface properties coil-to-coil – vital for uniform color coating behavior.

This chemistry is highly forgiving in paint lines: bake cycles, pre-treatment chemistries, and rolling sequences can be tuned without sudden embrittlement or drastic loss in elongation.

4. Mechanical Properties of A3004 H26 at 0.4mm

A defining feature of H26 at 0.4mm is the balance between stiffness and remaining ductility.

Table 2 – Typical Mechanical Properties (A3004 H26, 0.4mm)

Why this matters for a coated coil:

• Tension leveling & straightness:

  • Adequate yield strength maintains flatness after decoiling and tension leveling.
  • Minimizes coil set and “wave” under the paint film.

• Forming limit in final applications:

  • Even with H26, 0.4mm A3004 can be bent into many roofing, ceiling, and façade profiles with proper radii.
  • Careful tooling design (larger inner radii, polished rolls) preserves both coating and metal integrity.

5. Standard Compliance & Implementation Framework

To ensure consistency from the casting furnace to the building façade, A3004 H26 0.4mm color coated coils generally align with:

Aluminum substrate standards

Depending on target market and customer specification, base metal typically complies with:

• EN 573-3 – Chemical composition of wrought aluminium alloys.
• EN 485-1/2/4 – Mechanical properties, tolerances, and test methods for sheet and strip.
• Or equivalent:
  • GB/T 3190, GB/T 3880 (China)
  • Related national standards per region.

Color coating standards / systems

For architectural coils, paint performance is often specified by:

• EN 13523 series – Prepainted metal test methods (impact, bend, gloss, color, adhesion, etc.).
• ISO 2810 / ISO 6270 or ASTM G154/G155 – Accelerated weathering, UV and humidity.
• AAMA 2603 / 2604 / 2605 – North American performance criteria for architectural coatings
  (PVDF 70% based systems typically aligned to AAMA 2605).

Thickness and dimensional tolerances

0.4mm thickness is usually controlled within:

• Thickness tolerance
  • Typically ±0.02mm (or tighter per premium spec).
• Width tolerance
  • Commonly ±2.0mm or better, depending on slit width.
• Coil inner diameter (ID):
  • 405mm / 508mm / 610mm typical.
• Coil outer diameter (OD) & weight
  • Customized, often 2–4 tons per coil for easier handling at job sites.

The implementation insight:
Quality is not only “what alloy and coating you used” but whether mechanical and dimensional tolerances are tight enough for your forming line. Small variations in 0.4mm can drastically affect bending, pressing, and profile machine setup.

6. What “Color Coated” Technically Means in A3004 Coils

The value of A3004 truly emerges after coating. The full system is:

Base metal (A3004 H26 0.4mm)
→ Pre-treatment
→ Primer
→ Topcoat
→ Optional back coat

6.1 Pre-treatment

Typical conversion layers:

• Chrome-free or low-chrome systems:
  • Phosphate / zirconium / titanate-based.
• Purpose:
  • Improve corrosion resistance and paint adhesion.
  • Uniform wetting and bonding of organic coating.

Matching pre-treatment to A3004’s Al–Mn–Mg chemistry is important:
Mg-rich sweated areas during anneal and bake need proper chemical control to avoid paint adhesion defects.

6.2 Primer + Topcoat Systems

Common paint systems used on A3004 H26 0.4mm coils:

• Polyester (PE):
  • Cost-effective, good flexibility, suitable for interior & mild exterior.
• High-Durable Polyester (HDP):
  • Better chalk resistance, UV resistance than standard PE.
• PVDF (Fluorocarbon, e.g., 70% PVDF):
  • Premium UV, color, and gloss retention for high-end façades.
• SMP (Silicone-Modified Polyester):
  • Enhanced weatherability over conventional PE.

Typical total dry film thickness (DFT):

• Top side: 15–25 μm primer + 20–25 μm topcoat
  (Often 25 ± 5 μm in a single top layer for some PE systems, or 30+ μm for PVDF extremes.)
• Back side: 5–10 μm service coat or full backcoat as required.

The interaction is subtle: A harder coil temper (H26) combined with an adequately flexible system (like PVDF or high-quality PE) allows deep, yet crack-free bending—if minimum bending radii and process speed are respected.

7. Why 0.4mm is a “Sweet Spot” in Application

Designers and contractors often debate between 0.35, 0.4, and 0.5mm. For A3004 H26, 0.4mm is a balanced choice when:

• Weight is a constraint (e.g., curtain wall, soffits, ceiling, roller shutters).
• Surface aesthetics are critical (less chance of dents than thinner gauges).
• Profiles require light to moderate forming but not severe stretch drawing.

Common applications:

1. Building envelope & façade cassettes

   • 0.4mm allows lighter suspension systems and substructures.
   • A3004 H26 reduces “waviness” under sunlight vs lower-strength alloys at same thickness.

2. Residential & light industrial roofing

   • Metal tiles, sheets, and roll-formed profiles:
     • Good compromise between anti-dent behavior and ease of hemming, crimping, or seaming.

3. Interior ceilings and wall panels

   • Linear or clip-in ceilings: 0.4mm A3004 H26 yields crisp edges and stable joints.
   • Lighter ceilings → easier handling, less load on hanging grid.

4. Shutters & blind systems

   • Low inertia for effortless movement
   • Adequate stiffness to resist distortion and loud vibrations during operation.

In many of these cases, using A3004 instead of A1100/A3003 means one can reduce thickness slightly without compromising mechanical stability – a significant lifecycle cost and sustainability advantage.

The core lesson from a technical perspective:

A3004 H26 0.4mm color coated aluminum coil is a functional engineered system, not a commodity strip.

Its performance emerges through four synchronized choices:

1. Alloy design (A3004 Al–Mn–Mg)

   • Provides the mechanical foundation and corrosion resistance.

2. Temper (H26) tuned to 0.4mm

   • Determined hardening vs. ductility → affects dent resistance, shape retention, and forming margin.

3. Color coating system (PE / HDP / PVDF / SMP)

   • Balancing flexibility and weatherability with coil-handling conditions and target service life.

4. Standard-based implementation & QC (EN, GB, ISO, AAMA)

   • Guarantees repeatability: thickness tolerance, mechanical targets, coating adhesion, color consistency.

From the viewpoint of fabricators and project specifiers, choosing A3004 H26 at 0.4mm often means:

• Simpler forming setup: fewer rejections due to cracking or wrinkling.
• Cleaner surfaces on-site: fewer visible defects, dents, and waves.
• More predictable long-term color and gloss retention (when married to a robust coating spec).

9. Typical Technical Parameter Sheet (Integrated Example)

Below is a concise parameter snapshot that a specifier or purchaser might use:

Product: A3004 H26 Color Coated Aluminum Coil
Thickness: 0.40 mm (±0.02mm or per customer spec)
Width: 50–1600 mm (customizable)
Coil ID: 405 / 508 / 610 mm
Coil Weight: 2–4 tons (customizable)

Alloy & Temper:

• Alloy: A3004 (Al–Mn–Mg)
• Temper: H26

Chemical Composition: As per Table 1 (EN 573-3 or equivalent)

Mechanical Properties:

• Tensile Strength: 220–260 MPa
• Yield Strength: 180–230 MPa
• Elongation (A50): ≥2–4 %
• Hardness: corresponding to H26 per EN / GB standards

Coating System (Example – PVDF or Polyester):

• Pre-treatment: Chrome-free / environmentally compliant conversion layer
• Primer: Epoxy / Polyester, 5–10 μm
• Topcoat: PE / HDP / PVDF, 20–25 μm (or as specified)
• Backcoat: 5–10 μm service coat or full backcoat
• Color: RAL / NCS / custom color matching available
• Gloss: Matt, silk, or high gloss (typically 20–80 GU at 60°)

Standards Compliance:

• Base metal: EN 573-3, EN 485 series / GB/T 3190, GB/T 3880
• Coating tests: EN 13523 series, ISO / ASTM climatic and UV testing
• Optional: AAMA 2604 / 2605 alignment for high-end architectural finishes

10. Takeaways for Specifiers and Engineers

• Choose A3004 when:
  • You need higher strength and better stiffness than A3003 or A1100 at equal thickness.
• Choose H26 when:
  • 0.4mm parts must resist denting and maintain shape but still undergo moderate forming.
• Check standards and coating synergy:
  • Confirm both metal and coating specifications are harmonized to your forming process and exterior durability requirements.
• Consider lifecycle cost, not just initial gauge and price:
  • A properly specified A3004 H26 0.4mm coil can allow lighter structures, easier installation, fewer site damages, and longer repaint cycles.

3004   

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