Aluminum wins on weight and corrosion, steel wins on price and stiffness, and wrought iron wins on nothing but style, because the real thing is no longer made at scale. For a B2B buyer sourcing outdoor furniture from China, the decision is a trade-off between the FOB price and the cost of the frame failing in the customer’s yard. This guide puts numbers on that trade-off and tells you which frame to specify for which market.

The starting point is physics. Aluminum weighs about 2.7 g/cm3 against steel’s 7.85 g/cm3, so an aluminum frame of the same wall thickness is roughly 60% lighter. In our Foshan order book, aluminum-framed furniture quotes 20-40% higher FOB than painted steel for the same design, and steel frames fail in coastal conditions after 3-7 years where aluminum frames from the same programs pass 10.

The Three Frame Materials at a Glance

This is the spine of the decision. Every outdoor frame you will be quoted in Foshan sits somewhere in these three rows, and the choice comes down to where your product sells, not which material is “better”.

Frame	Weight	Corrosion	FOB vs steel	Best for
Aluminum	~60% lighter	Oxide layer, no rust	+20-40%	Coastal, hotels, e-commerce freight
Steel	Baseline	Rusts once coating fails	Baseline	Budget retail, inland markets
Wrought iron style	Heaviest	Rusts, needs maintenance	Mid range	Traditional hospitality, garden decor

The FOB premium and corrosion figures come from Riwick’s own outdoor programs, not from a brochure. The rest of this guide explains when the 20-40% aluminum premium pays for itself and when it is wasted margin.

Aluminum Frames: The Coastal Default

Aluminum does not rust because it forms its own oxide layer, and that single property is why it dominates coastal and hospitality outdoor furniture. In our coastal export programs, powder-coated aluminum frames from Foshan suppliers typically run 1.2-2.0 mm wall thickness, which is enough for a dining chair or lounge set while keeping the piece light enough for one person to move. The premium powder lines report 500+ hours in neutral salt spray testing, against the 72-hour minimum our inspection records use as the acceptance threshold for outdoor frames.

The trade-offs are real. Aluminum is softer than steel, so thin extrusions bend under heavy commercial use, and repairs need TIG welding with a clean surface, which most field repair shops cannot do. Frames for contract use must be specified at the heavier end of the wall range. The frame also costs more: the 20-40% FOB premium over painted steel is the price of the material, the extrusion dies and the better coating line.

When the premium pays: any program shipping by volume, any order going to a coastal or resort market, and any retailer whose customers return furniture when it rusts. When it does not: a low-price promotion line for an inland market where the frame will live under a covered porch. The material comparison logic mirrors what we wrote for teak versus acacia versus eucalyptus: match the material to the exposure, not to the showroom.

Steel Frames: The Price Leader

Carbon steel is the baseline of the outdoor furniture market for one reason: it is cheap and stiff. Foshan steel frames commonly use 1.0-1.5 mm tube, and the mechanical properties of the structural grades are defined by standards such as ASTM A36 structural carbon steel, which buyers reference when they specify minimum yield strength. A steel frame shrugs off the abuse a commercial terrace dishes out, and when it breaks, any local welder can fix it.

Steel’s weakness is corrosion, and the timeline is brutal in the wrong climate. Powder-coated steel that starts with a pin-prick scratch in a coastal garden develops rust bloom within months, and in our coastal programs buyers replaced steel-framed sets after 3-7 years while aluminum frames from the same orders stayed in service past 10. The coating is the whole game: surface prep, zinc-rich primer and a quality topcoat determine whether a steel frame lives in the sun or dies in the salt.

Steel is also a freight problem. A 40HQ container carries a maximum payload of roughly 26,500 kg, and heavy steel furniture hits that weight limit before the volume limit, which raises freight per unit exactly when you are trying to win a low price. For inland, price-driven programs steel remains the right call, and the weather-resistant outdoor furniture sourcing guide walks through the coating specs that keep steel alive longer.

Wrought Iron Frames: Style Over Substance

True wrought iron, the hand-forged material of 19th-century balconies, is no longer produced at scale, and almost every “wrought iron” outdoor furniture set sold today is mild steel tube bent and welded into a traditional design, or aluminum cast and coated to imitate it. Foshan suppliers in the forging and tube-bending districts will happily quote a scroll-arm bench or a filigree bistro set; what you are buying is a style, not a material.

That distinction matters in the spec. If the look requires sharp scrolls and tapered legs, expect heavier tube and more weld cleanup, which pushes the quote into the middle of the price range. If the product must actually survive outdoors, specify powder coating with the same salt-spray threshold as any steel frame, because the classic black finish hides rust until the paint bubbles and the customer photographs it.

The buyer for wrought-iron style is the traditional hospitality operator, the garden-center decor line and the Mediterranean-style terrace. The buyer who should avoid it is the coastal hotel, where the maintenance budget will eat the aesthetic. If the same traditional silhouette is needed at the coast, specify the aluminum imitation and say nothing at the sales meeting.

Corrosion and Finishing Reality

Every outdoor frame decision is really a coating decision. The common acceptance threshold across our supplier network is 72 hours of neutral salt spray with no blistering, and premium aluminum programs report 500+ hours. Coating adhesion is verified with cross-cut tape tests, and the reference method is ASTM D3359 adhesion test standard, which buyers can ask the factory to run on a production sample.

Ask for three things at quoting: the wall thickness, the coating system, and the salt spray report. A steel frame with a zinc-rich primer and a two-coat topcoat is a different product from the same frame with one coat of black paint, at nearly the same price. In our inspection records, coating failure is the second most common outdoor furniture defect after weld quality, and both are visible in a 10-minute factory check.

If you need to identify a frame in the field, the magnet settles it in five seconds: a magnet sticks to steel and to the steel core of wrought-iron style pieces, and slides off aluminum. Scratch depth is the second test: aluminum scratches to a silvery base while steel shows the darker coating layer. Warehouse teams use both before accepting a mixed container, because mislabeled frames are a regular occurrence when one program sources the same design in two materials.

Cost, Freight and MOQ Math

The FOB delta is the headline: aluminum 20-40% above painted steel for the same design. The freight delta runs the other way. A 40HQ loads about 68 cubic meters, and because aluminum is lighter, an aluminum program fills the container by volume and ships more units per freight dollar, while a steel program can hit the 26,500 kg payload ceiling with space to spare. On dense products like chairs and benches, the freight saving on aluminum covers 10-20% of the FOB premium, shrinking the real gap to single digits.

MOQs follow the tooling. Standard steel and aluminum catalog frames quote from 50-100 sets in our outdoor programs. A custom aluminum extrusion means a die, which in Foshan runs roughly $800-$2,000 depending on profile complexity, and that die cost is why custom aluminum programs start at 200-300 units while custom steel tube frames, which need only bending and welding tools, can start lower. Our outdoor furniture MOQ case study shows how one retailer scaled a 500-unit aluminum program, and the container loading guide covers the freight-side math in detail.

Which Frame for Which Buyer

Resort and coastal hotels should specify aluminum and amortize the premium over a decade of service. Budget retailers selling inland should take steel, specify the coating, and plan for a 3-7 year product life. Traditional hospitality and garden decor should use the wrought-iron style in steel for the price and in aluminum for coastal exposure. E-commerce brands shipping single sets should favor aluminum, because the 60% weight saving cuts courier and freight claims at once.

Buyer profile	Frame to specify	Why
Coastal resort or hotel	Aluminum, 1.5-2.0 mm	Salt resistance, 10+ year service
Budget retail, inland	Steel with quality coating	Lowest landed cost
E-commerce single sets	Aluminum	Lighter freight, fewer damage claims
Traditional hospitality	Wrought-iron style	Aesthetic, moderate budget

One warning applies to every row: verify the wall thickness on the production sample, because the quote for a 1.2 mm aluminum frame and a 1.0 mm frame looks identical until the first chair collapses under a heavy guest. The rattan versus wicker versus bamboo guide covers the companion decision for the weave, and our furniture materials and hardware page lists the full material range we source for outdoor programs.

Frequently Asked Questions

Conclusion

Specify aluminum for coastal and commercial exposure, steel for inland price programs, and the wrought-iron style only where the look is the sale. Then verify wall thickness and salt spray on the production sample, because the coating and the tube decide how long the frame lasts.

Send us your outdoor product list and target markets, and we will quote the same design in aluminum, steel and wrought-iron style side by side, with the freight math and the salt spray reports before you choose.