• Key Takeaways
• Defining Aluminized Sheet
  • 1. The Steel Core
  • 2. The Coating
  • 3. Type 1
  • 4. Type 2
• The Manufacturing Process
  • Surface Preparation
  • Hot-Dip Coating
  • Post-Treatment
• Core Properties
  • Heat Reflectivity
  • Corrosion Resistance
  • Formability
• Common Applications
  • Automotive
  • Appliances
  • Construction
  • Industrial
• Material Comparison
  • Versus Galvanized
  • Versus Stainless Steel
• Design Considerations
  • Welding
  • Forming
  • Fastening
• Conclusion
• Frequently Asked Questions
  • What is aluminized sheet?
  • How is aluminized sheet manufactured?
  • What are the key properties of aluminized sheet?
  • Where is aluminized sheet commonly used?
  • How does aluminized sheet compare to galvanized and stainless steel?
  • What design considerations should I keep in mind?
  • Can aluminized sheet be welded and painted?

Key Takeaways

• Aluminized sheet marries a high-strength steel core with a corrosion-resistant aluminum or aluminum-silicon coating that excellently reflects radiant heat. Choose product form – sheets, panels, or coils – to suit your handling, throughput, and downstream fabrication requirements.
• Choose the steel substrate for mechanical objectives since the core determines yield strength, formability and weight while the coating safeguards surfaces. Design with carbon or alloy grades matched to structural loads and forming depth.
• Match coating type to the environment – Type 1 with 5 to 11% silicon excels at high temperature and oxidation while Type 2 with pure aluminum maximizes corrosion resistance. See ASTM A463 for coating composition and thickness.
• Hot-Dip Coating with thorough surface preparation and post-treatment to provide adhesion, evenness and stable aluminum oxide formation. Add process controls and inspection for coating integrity, thickness and appearance to specification and longevity requirements.
• Leverage key attributes like heat reflectivity, corrosion resistance and excellent formability to save energy and prolong service life in ovens, HVAC units, siding, storage tanks and bakeware. Save the coating through stamping, bending and deep drawing with appropriate tooling and surface protections.
• Match materials to duty because aluminized steel resists heat better than galvanized and, in many cases, provides a cost and weight advantage over stainless. Take the best practice approach to welding and fastening – reduce heat input where possible, clean your joints, select fasteners with compatible metals, and seal any breached areas to preserve the corrosion protection.

Aluminized sheet is steel coated with aluminum or an aluminum‑silicon alloy to provide excellent heat and rust resistance. It resists heat, retains shape under strain and maintains a clean face in steam or warm air. Typical applications are car exhaust components, ovens, as duct work and roofing. Two main types exist: Type 1 (Al‑Si) for heat service and Type 2 (pure Al) for wet service. Standard grades to ASTM A463, service temperatures 650 °C.

Defining Aluminized Sheet

Aluminized sheet is steel coated by aluminum or an aluminum–silicon alloy to increase surface life and heat management. Aluminized sheet defined: the core supports load, the coating stops corrosion and reflects heat. The stack is three layers: a thin aluminum oxide film on top, a stable Al–Fe intermetallic layer, and the steel core beneath.

• Product forms: flat sheets, slit coils, wide coils, stamped panels, welded panels, and roll-formed shapes, used across automotive, HVAC, appliances, construction, agriculture, and energy

1. The Steel Core

The steel substrate provides strength, stiffness and fatigue life. It establishes yield, tensile and dent resistance.

Grades span from low-carbon deep-draw steel to microalloyed high-strength steels. Selection based on bend radius, draw depth, and crash or pressure loads.

Core thickness and grade determine mass per area, therefore weight goals dictate gauge choice. In hard forming, the softer cores lower the risk of splitting and in frames, stronger cores minimize creep and distortion.

2. The Coating

Coating is a hot-dip, thin aluminum or Al–Si layer. It creates an adherent intermetallic zone that bonds the coat to steel. Per ASTM A463, composition and mass are quoted; Type 1 is Al–Si (around 5–11% Si) and Type 2 is near-pure Al. Thickness tuned to service class + environment The coat is a barrier to moisture, salts, and combustion gases and it forms an oxide that limits any further attack. It reflects radiant heat very well, with Type 1 capable of reflecting up to 80% and sustaining approximately 677C (1250°F) in service by virtue of the intermetallic layer’s stability. In typical applications, corrosion resistance is robust below aluminum’s melt point, 660°C (1220°F). Process steps matter: clean the steel, hot dip in Al–11%Si at about 988 K, then air dry to lock in adhesion and surface finish.

3. Type 1

Type 1 is hot-dip coated with an aluminum–silicon alloy, typically 5–11% Si. The silicon enhances wetting, restricts brittle intermetallic growth and maintains the coat adhered during forming and thermal cycling. It exhibits superior oxidation resistance at elevated temperatures, hence its presence in automotive mufflers and exhaust components, ovens, ranges, water heaters, fireplaces, heat exchangers, furnaces, and industrial cladding.

Choose it when components experience intermittent heat, direct flame, or flue gases.

4. Type 2

Type 2 uses a near-pure aluminum coating but does not contain silicon. It prefers maximum corrosion resistance in mild to moderate atmospheres.

You see it all the time in siding, roofing, grain bins and storage tanks. Used in ducting, exterior panels and general building products.

Select Type 2 for when the heat is moderate but wet cycles prevail. It handles coastal inland areas better than bare steel, with easier forming and weld prep.

Service life gets better with edges sealed, fasteners matched.

The Manufacturing Process

Aluminized sheet is produced by coating steel with aluminum using a hot-dip line, operated under rigorous process control to provide uniform coating thickness, excellent adhesion and uniform surface appearance through various product grades and finishes.

Surface Preparation

Steel comes onto the line with oil, dirt and scale from prior processes. The surface is washed and completely de-greased with alkaline spray or electrolytic cleaning to remove oils and fine residues that can interfere with bonding.

Any rust and mill scale is removed by pickling in controlled acid baths or light mechanical brushing. This step removes the iron oxide layers so the aluminum can wet the surface and interact with the steel.

A quick rinse and drying cycle comes next to keep the sheet clear of salts and water.

Hot-Dip Coating

The cleaned steel is passed through a molten bath of aluminum or an aluminum–silicon alloy at precise temperatures, usually around 660–700°C, where immersion time, bath chemistry (e.g. 5–11% Si for heat resistance), and line speed are adjusted to the desired coating weight. The hot metal wets the steel and forms a true metallurgical bond via diffusion at the interface, generating intermetallic layers that both mechanically lock the coating in place and enhance peel strength. As strip exits, gas knives wipe excess metal to set thickness across width, while closed-loop sensors test mass per area in real time to maintain tight tolerances. As it cools, a thin, stable aluminum oxide skin naturally forms on the surface, providing an additional barrier protection and assisting the sheet in resisting both heat and corrosion. These parameters are tweaked to manufacture versions for ducts, exhaust components, cookware shells, or construction panels, each with varying coating weight, reflectance, or malleability.

Post-Treatment

After the bath, the sheet is cooled in air or inert gas, and then leveled to eliminate coil set and minor wavy distortions. Surface finishing can be temper rolling for gloss control or micro-brightness, and light oiling to assist forming. A few lines passivate (usually thin inorganic layer) to increase corrosion resistance and minimize storage stain. Quality inspections confirm coating adhesion, thickness consistency, and surface class according to ASTM, with peel tests, bend tests, and visual inspection employed to detect imperfections promptly.

Up stream supply issues to consider. Aluminum is not found in pure form. It is made from bauxite using three steps: mining bauxite, refining to alumina with the Bayer process (Karl Josef Bayer, 1888), and smelting alumina to aluminum by the Hall–Héroult process (invented in 1886 by Charles Hall and Paul Héroult). Around 85% bauxite to alumina, 2 lbs. Alumina = 1 lb. Aluminum, reserves for centuries.

Core Properties

Aluminized sheet pairs a steel core with an aluminum or aluminum‑silicon coat, providing a useful blend of strength, heat resistance and corrosion resistance. Standard density is 7.85 g/cm³, so weight remains reasonable for large plates. Tensile strength often falls in the 350–550 MPa range, with yield strength close to 200–300 MPa, which is sufficient for light structural components that still require neat surfaces.

• Maintains structural durability and surface appearance over time
• Balance of steel strength and aluminum protection
• Suitable for harsh environments and high‑temperature service
• Helps cut upkeep in outdoor and thermal cycling conditions

Heat Reflectivity

The aluminum layer is a good reflector of radiant heat, so less energy is absorbed into the sheet, and less heat passes to the other side, which is why it shows up in ovens, space heaters, furnace panels, and engine bay heat shields. The reflective surface reduces heat load, which can shave energy consumption in temperature-sensitive equipment, particularly where steady-state temperature is more important than short spikes. Thermal conductivity near 50 W/mK facilitates fast heat spreading that prevents hot spots, and a specific heat of approximately 0.46 kJ/kgK assists with buffering swings during heat-up and cool-down periods. It maintains form up to approximately 550 °C with minimal effect on the base metal, and its melting range around 660–700 °C offers a buffer for occasional spiking. Versus bare carbon steel aluminized sheet maintains higher reflectance at elevated temperature and resists scale so performance remains stable; versus stainless grades it has excellent radiant reflectivity at a lower cost across many duty cycles with similar weight due to steel core.

Corrosion Resistance

The covering creates a bond with a tight aluminum oxide layer that prevents water, salts and numerous combustion by‑products, so base steel does not pit or corrode readily. This passive layer is self‑healing when scratched, within reason, prolonging life in wet‑dry cycles.

The relatively high resistivity (~1×10⁻⁶ Ω·m) can reduce galvanic currents between dissimilar metals in some joints.

Checklist:

• Rooftop HVAC housings and ducts
• Exterior siding and soffits
• Storage tanks and grain bins
• Chimney liners and flues
• Exhaust hoods and industrial ovens

Formability

Sheets maintain excellent formability for stamping, roll forming, hemming and deep draw. The steel core supports strain and the metallurgical bond minimizes flake‑off, provided bend radii, draw ratios and lubrication are carefully selected. Smooth dies and guarded handling prevent deep scratches that break the coat. Correct blanks, draw beads, and clean oils preserve surface quality despite several hits.

This is a no brainer for automotive heat shields and inner panels, appliance housings and bakeware where a bright, clean face counts. Notice the machinability index is around 60, so drilling and milling go slower than free-machining steels. Cut with sharp cutters and moderate feeds.

Common Applications

Employed structural and non-structural applications, aluminized sheet combines steel’s strength with the heat and rust-resisting properties of an aluminum-silicon coating. It endures as high as 550 °C (1,022 °F) with minimal alteration to the substrate metal, accounting for its ubiquity across transportation, architecture, appliances, and process equipment. North America consumes nearly 700,000 tons annually for water heaters, ranges, furnaces, space heaters, grills and beyond.

1. Vehicles: mufflers, full exhaust lines, motorcycle exhausts, patch panels, bumper beams.

2. Appliances: kitchen ranges, ovens, dryers, water heaters, fireplaces.

3. Food service: bakery trays, cooking sheets, muffin pans, roasting pans.

4. HVAC: residential furnaces, air‑conditioner condenser housings, commercial rooftop units.

5. Construction: corrugated roofing and siding, grain bins, storage tanks.

6. Industrial: drying ovens, heat exchangers, furnaces, space heaters, Type 2 jacketing and cladding over insulation and pipes that carry steam or acids. Something like this, maybe, for quick industry-to-product type scans.

Automotive

Aluminized sheet is popular in mufflers, resonators, tailpipes and complete exhaust systems due to the coating’s resistance to hot condensate, chlorides and sulfur compounds from exhaust gas, while minimizing scale growth at elevated temperatures. In arid areas, they typically last for over eight years, but in temperate climates, replacements are needed within three to five years, from moisture and de‑icing salts. Automakers tap the metal for patch panels and body panel repair kits where corrosion resistance and weldability count and for some bumper beams or shields where weight goals drive engineers to thin gauges without sacrificing stiffness. Motorcycle exhaust parts lean on the same heat and oxidation resistance, with lighter weight than numerous stainless options at comparable formability and price.

Appliances

Kitchen ranges, ovens, clothes dryers and water heaters use aluminized sheet for hot boxes, liners, burner pans and flues – the coating safeguards against oxidation cycles and humid storage, while the steel core retains form and strength at heat. Fireplaces and barbecue burners utilize it for firebox panels and shields, and bakeware–cooking sheets, muffin pans, and roasting pans–reaps lower oxide accumulation than bare steel, which prolongs tool life in repeated thermal cycling.

The brilliant finish cleans with easy swipe-wipes, appliance brands love for consumer-maintenance and showroom sheen.

Construction

Roofs and sidings, particularly corrugated panels, enjoy extended service in seaside and desert regions because of their robust corrosion resistance.

Commercial rooftop HVAC housings utilize it for skins, doors, and bases, balancing weight, cost, and weathering.

Grain bins and storage tanks — Type 2 or heavy‑coat sheet for structural performance against wet feedstocks and seasonal thermal swings.

Because of high solar reflectance, it can reduce cooling demand in hot climates when applied to roofs or sun‑exposed walls.

Industrial

Heat exchangers, furnaces, space heaters, and drying ovens all use aluminized sheet for housings, guards and combustion chambers that are exposed to constant, high heat and oxidation.

Type 2 aluminized steel is the standard for cladding and jacketing over insulation, as well as pipes carrying steam or acidic/corrosive media.

Chemical resistance holds up air‑heater ducts, scrubber shells and condenser housings in severe service.

Plants love it for insulation lagging because it forms well, sheds water and stands up to UV and thermal shock.

Material Comparison

Concentrate on corrosion resistance, heat resistance, weight, and cost for aluminized sheet, galvanized steel and stainless steel. A simple matrix can help guide choices, and then you can validate against your load case, duty cycle and environment. Make a pros and cons table for rapid screening.

Material	Advantages	Drawbacks
Aluminized steel	Strong steel core; high heat resistance; good corrosion in many atmospheres	Coating can crack on severe forming; not marine-grade; mid cost
Galvanized steel	Low cost; broad corrosion protection in non-heated service	Poor high-temp tolerance; zinc fume risk at heat; aesthetic weathers
Stainless steel	Excellent corrosion; high durability; clean surface	High cost; higher forming force; heavier than aluminum options

Versus Galvanized

Aluminized steel, a steel substrate coated with an aluminum–silicon layer, holds up well at heat due to the stable alumina scale and silicon diffusion barrier. Typical service temperature can reach about 650°C without severe coating failure. Galvanized steel relies on zinc, which protects steel by sacrificial action and barrier film in ambient and mildly heated service, yet zinc softens and oxidizes quickly above about 200–250°C, and the coating can peel or vaporize near 420°C, which rules it out for hot zones. This is why aluminized grades are common in ovens, catalytic converter shells, mufflers, and heat shields, where radiant heat and cyclic thermal loads demand both reflectivity and oxide stability. The aluminum layer reflects infrared and slows scale growth, while the steel core provides strength at temperature. In non-heated or low-heat environments—roof panels, cable trays, HVAC ducting, fencing—galvanized sheet often wins on price and availability. It is easy to spot-weld, easy to paint after passivation, and delivers broad corrosion coverage in rural and many urban atmospheres. Select based on exposure: wet-dry cycling with de-icing salts favors heavy zinc coatings. Sustained heat or exhaust condensates favor aluminized coatings. Splash zones with chlorides need upgrades or sealing.

Versus Stainless Steel

Stainless steel attains corrosion resistance by chromium-rich passive films, with 304 and 316 stainless performing well in most industrial environments, though cost per kg and forming force are higher than aluminized sheet. Aluminized sheet offers excellent heat reflectivity and good corrosion resistance for numerous enclosures, appliances and exhaust components, at a lower cost and more straightforward fabrication. It’s lighter per panel when gauge is reduced for reflectivity, but keep in mind steel’s density (~ 7.8) remains greater than aluminum (~ 2.7) and steel’s higher density is often accompanied with higher strength at the same thickness.

When weight is a hard limit, compare against aluminum alloys: 5052 resists corrosion well, even in marine spray. 6061 contributes strong impact resistance from Mg–Si. 7075 provides high tensile strength from zinc but sacrifices corrosion, especially as its copper content increases. Alloy series matter: 1000 is near-pure, 5000 uses magnesium for corrosion performance, and copper additions can cut corrosion resistance. If heat beyond 250°C is commonplace and budgets lean, aluminized sheet becomes a convenient compromise. If chloride-heavy or food-grade settings prevail, stainless is more secure despite cost.

Design Considerations

Aluminized sheet provides the strength of steel with an aluminum-based coating of heat and corrosion protection. Design decisions around welding, forming, and fastening establish the upper limit on performance, life, and finish, so design for coating integrity starting at the initial sketch. Match sheet type and thickness to service load, heat range and environment, check Air bend force charts and coating class prior to tooling.

Welding

Aluminized steel is weldable, although the coating requires protection to remain intact. Address design considerations and use processes and settings that keep heat input low—short-arc GMAW, pulsed transfer, GTAW with controlled amperage, or resistance spot welding with dressed electrodes and tight schedules. Up to 700 ºC, enough to vaporize the aluminum layer, expose bare steel, and accelerate oxidation in the vicinity of the joint – local fume extraction is mandatory because of the aluminum fumes. Mechanically clean the weld area — no oils, no oxides, and if you strip the coating at the joint, make it the smallest workable band. Select filler metals compatible with the steel substrate and considerate of the coating—want sound fusion without overwetting edges. Backside shielding (or copper backing) minimizes burn-through and spatter that would mar the coating. When welding, clean off flux residues, inspect for coating burn-off and touch up exposed steel with aluminized touch-up or aluminum-rich paint to re-establish barrier protection.

Forming

Smooth, hard tooling with generous radii should be used to avoid cracks or flaking of the aluminum coating. Sharp dies and small punch radii increase local strain and scratch the coating.

Aluminized sheet can be formed nicely for complex draws if you control strain trajectories. Minimize inside bend radius to a default of 1.0–1.5× thickness for standard bends. For deep draws increase radii and utilize consistent lubrication.

Locate holes minimum 6× thickness apart and 2.5× thickness + bend radius from bends. For minimum flange length, the distance from the outside to bottom of a cutout should satisfy the air bend force chart’s minimum flange guidance. For holes or slots less than 25mm, D = 2t + r to Hole 2 center; for everything else, D = 2.5t + r. Bend allowance varies with the K‑factor (0–0.5), which you can customize by averaging three bent samples to calibrate flat patterns. Hemming requires a flange length of at least 4× thickness, keep tabs 2× thickness or 3.2 mm, whichever is greater. For extruded holes, maintain 1–2 mm spacing between parts to prevent crossover cutting, and space two extruded holes apart at 6× thickness. Notching is cost efficient with conventional punches—employ it to reduce corner relief and avoid stressing the coating.

Trial runs on sample blanks allow us to lock in radii, clearances, lube and press tonnage before going to scaled production.

Fastening

Select fasteners that will not cause galvanic mismatch or damage to the coating. Use aluminized or zinc‑plated carbon steel hardware whenever possible, or isolate dissimilar metals with nylon washers, plastic bushings, or sealants. Match fastener type-self-tapping screws for light assemblies, rivets for thin stack-ups, bolts for serviceable joints-to load case and environment (temperature, moisture, salt, chemicals). Pre‑drill clean holes, deburr edges and maintain hole spacing rules from forming to safeguard coating near bends and flanges. If installation damages the coating, paint or sealant with aluminum content under heads and in threads to maintain an unbroken protective layer, and manage torque to restrict fretting. Check fastener locations post-assembly to ensure complete coverage and no bare steel.

Conclusion

Aluminized sheet gets the nod for heat, rust and cost. The steel core imparts high strength. The Al-Si coat blocks scale and rust in wet air. The bond maintains above 600 °C. Welds stay clean with the right wire and gas. Bends look sharp with the proper die. Thin stock, as 0.8 mm, is suitable for ducts. Thicker stock, say 2.5 mm, suits heat shields.

In actual applications, it glistens in bake ovens, vent lines and automobile exhaust heat guards. It outperforms plain steel in hot air and salt spray. It’s less than full stainless for the same work.

Want an easy action to take? Chart your heat spectrum, stream, and breadth. Forward your target temp and sheet gauge and we’ll forward your weld plan. I can assist in selecting a grade and test cutting.

Frequently Asked Questions

What is aluminized sheet?

Aluminized sheet is steel coated with aluminum or aluminum–silicon alloy. The coating metallurgically adheres to the steel. It provides corrosion resistance, heat reflectivity and increased durability for use where heat and oxidation are a concern.

How is aluminized sheet manufactured?

By hot-dipping steel in molten aluminum or aluminium–silicon alloy. It creates an intermetallic layer for powerful bonding. Precise cooling guarantees consistent coat thickness. Which gives you uniform surface finish and dependable results.

What are the key properties of aluminized sheet?

It provides high heat resistance (to approximately 677°C for Type 1), excellent corrosion resistance, and good formability. This surface reflects radiant heat. It exhibits dimensional stability in thermal cycling. It welds and paints fine with proper prep.

Where is aluminized sheet commonly used?

It’s utilized in automotive exhausts and shields, ovens, grills, HVAC components, industrial ducts and combustion chambers. These applications require heat resistance, oxidation resistance and long service life. Aluminized sheet – Does well in moderate to high temperatures.

How does aluminized sheet compare to galvanized and stainless steel?

Versus galvanized: better heat resistance and oxidation protection, similar formability, often higher temperature limits. Versus stainless: lower cost and better heat reflectivity, but less corrosion resistance in chlorides and harsh chemicals. Select based on environment, temperature and budget.

What design considerations should I keep in mind?

Indicate coating type (Type 1 Al–Si or Type 2 pure Al), coating mass, and gauge. Remember thermal expansion and temperature exposure. Employ appropriate bend radii to avoid cracking. Consider weldability and post-weld coating repair if applicable. Think about drainage and avoiding crevices.

Can aluminized sheet be welded and painted?

Yes. Employ suitable welding processes (resistance spot, MIG) with fume extraction. Strip coating locally if necessary. Once welded, guard exposed areas with compatible coatings. For painting, wash and lightly pretreat for adhesion.