The comparison between light steel keels and aluminum alloy keels

I. Material Essence and Basic Properties

Comparison Dimension	Light Steel Keel	Aluminum Alloy Keel
Material Composition	Made from galvanized steel strips (Q235 steel), formed by cold bending, with a galvanized (hot-dip or electro-galvanized) anti-corrosion surface.	Manufactured from aluminum base material with added alloying elements like magnesium, silicon, and manganese, with a density about 1/3 that of steel (approximately 2.7g/cm³).
Density and Weight	High density (7.85g/cm³), heavier in weight for the same 规格，requiring consideration of load-bearing during transportation and installation.	Low density, lightweight, easy to carry and install by a single person, reducing construction labor intensity.
Flexibility and Processability	High strength but lower flexibility, requiring professional tools (e.g., cutting machines, punching machines) for processing; custom fittings needed for complex shapes.	Excellent ductility, easy to cut and bend, allowing for curved or irregular shapes using manual or simple tools, offering flexible construction.

II. Core Performance Comparison

1. Load-Bearing Capacity

Light Steel Keel:
High tensile strength (yield strength ≥235MPa), suitable for medium to high-load scenarios, such as supporting gypsum boards, double-layer panels in ceilings, or as a skeleton for partition walls. Note: Standard specifications (e.g., 50/60 series for ceilings) are only suitable for light loads; increased density or larger specifications (e.g., 75/100 series) are required for heavy loads.
Aluminum Alloy Keel:
Lower strength than steel (tensile strength approximately 150–300MPa, depending on the alloy), mainly used for light-load scenarios, such as supporting mineral wool boards, aluminum 扣板，or lightweight gypsum boards. Not suitable for heavy ceilings (e.g., hanging large lights or equipment) or load-bearing partitions.

2. Corrosion Resistance

Light Steel Keel:
Relies on the galvanized layer for anti-corrosion; prone to rust if the coating is damaged (especially in wet environments), requiring regular maintenance. In bathrooms, kitchens, or coastal areas, moisture-resistant gypsum boards or additional anti-corrosion coatings are needed.
Aluminum Alloy Keel:
Naturally forms a dense aluminum oxide film on the surface, with excellent corrosion resistance. No additional treatment is required for long-term use in wet or high-humidity environments (e.g., bathrooms, swimming pools), and it outperforms steel in acid and alkali resistance.

3. Fire Resistance

Light Steel Keel:
Steel has a melting point of about 1500℃ but loses strength rapidly above 300℃, with a fire resistance rating typically 0.5–1 hour (requires fire-resistant gypsum boards). Fireproof coatings are needed for high-rise buildings.
Aluminum Alloy Keel:
Melting point around 660℃, lower than steel, more prone to softening at high temperatures. Fire resistance is slightly inferior to light steel keels, also relying on fireproof panels to improve fire ratings.

4. Sound and Thermal Insulation

Both are metallic materials, suffering from “sound bridges” and “thermal bridges,” requiring filling materials like soundproof cotton or rock wool for improvement; differences are minimal.

5. Deformation Resistance

Light Steel Keel: High rigidity, less prone to bending over time, but susceptible to thermal expansion and contraction (expansion joints need to be 预留) due to temperature changes.
Aluminum Alloy Keel: Thermal expansion coefficient about twice that of steel, more obvious deformation in high-temperature environments; spacing and fixing methods must be noted during installation.

III. Application Scenario Differences

Scenario	Light Steel Keel	Aluminum Alloy Keel
Ceilings	Suitable for gypsum board ceilings, double-layer composite ceilings, and heavy equipment hanging (with reinforcement), common in living rooms, offices, and corridors.	Suitable for light-load ceilings with aluminum 扣板，mineral wool boards, or calcium silicate boards, common in bathrooms, kitchens, and commercial spaces (requiring aesthetic surface treatment).
Partition Walls	Used for lightweight partitions (e.g., office dividers, residential 分户 walls), capable of supporting wall decorations (e.g., tiles, stone).	Rarely used for partitions, only suitable for extremely lightweight partitions (e.g., glass partition frames) or decorative dividers.
Wet Environments	Requires additional moisture-proof treatment; otherwise, prone to rust, with limited use.	Naturally moisture-resistant, no special treatment needed, the preferred choice for bathroom and shower ceilings.
Outdoor or Highly Corrosive Scenarios	Requires thickened galvanized layers or anti-corrosion treatment, high cost; generally not recommended.	Can be directly used for outdoor sunshades, balcony ceilings, or corrosive environments like chemical plants and coastal buildings.
Complex Shapes	Requires custom fittings or welding, high construction difficulty and cost.	Easy to process and bend, suitable for personalized ceiling shapes like arcs or circles, with high construction efficiency.

IV. Construction and Cost

1. Construction Difficulty

Light Steel Keel:
Requires electric tools (e.g., drills, rivet guns) for fixing; fittings (hangers, connectors) rely on bolts or welding, with high precision requirements (e.g., levelness and spacing errors ≤3mm), suitable for industrialized construction.
Aluminum Alloy Keel:
Fittings are mostly snap-in or plug-in designs (e.g., T-type, L-type keels), adjustable by hand or simple tools during installation, fast construction speed, suitable for on-site manual operation and quick installation.

2. Cost Comparison

Material Cost:
Aluminum alloy keels are 1.5–2 times more expensive than light steel keels (e.g., ordinary ceiling light steel keels cost approximately 8–15 RMB per meter, while aluminum alloy keels cost 15–25 RMB per meter), but fitting costs are lower (fewer bolts and hangers needed).
Maintenance Cost:
Light steel keels require regular anti-corrosion treatment in wet environments, with high long-term maintenance costs; aluminum alloy keels require almost no maintenance, offering lower life-cycle costs.
Service Life:
Light steel keels last 10–15 years under normal use (halved in wet environments); aluminum alloy keels can last over 20 years.

V. Environmental Protection and Recycling

Light Steel Keel: 100% recyclable, but galvanized layer treatment may generate pollutants, requiring professional recycling.
Aluminum Alloy Keel: High recycling rate, with recycling energy consumption only 5% of primary aluminum, offering stronger environmental advantages.

Summary: How to Choose?

Choose Light Steel Keel:
Suitable for medium-heavy load, non-wet environments, and cost-sensitive scenarios (e.g., living room ceilings, office partitions), with attention to fire and moisture protection.
Choose Aluminum Alloy Keel:
Suitable for light-load, wet environments, and scenarios requiring construction convenience or personalized shapes (e.g., kitchen/bathroom ceilings, outdoor decorations), with higher long-term cost-effectiveness.

The core differences lie in load-bearing capacity, corrosion resistance, and construction flexibility, which should be comprehensively evaluated based on specific building environments (humidity, load), budget, and design requirements.