Aluminum extrusion is a process where aluminum billets are heated to 450–500 °C and forced through a steel die to create profiles with a specific cross-sectional shape. The extruded length is then cooled, stretched (to relieve internal stress), and cut to specified lengths. After extrusion, profiles typically undergo artificial aging (T5 or T6 temper) to achieve the desired mechanical properties.
China produces over 25 million tons of aluminum extrusions annually — more than half the world's total. For overseas buyers, Chinese extrusion offers significant cost advantages on die fabrication, billet material, and processing, but navigating profile design optimization and surface finish quality can be tricky without local know-how. This guide covers what you need to know before sourcing.
| Parameter | Typical Range | High-End / Precision |
|---|---|---|
| Alloy Grades | 6061, 6063, 6005, 6082, 6060 | 7075, 2024, 3003 |
| Temper Options | T5, T6 | T6511 (stress relieved) |
| Max Profile Circumference | 300–800 mm | Up to 1,200 mm (3500-Ton press) |
| Wall Thickness | 1.0–12.0 mm | 0.6–1.0 mm (precision dies) |
| Linear Tolerance | ±0.5 mm / m (GB/T 5237) | ±0.15 mm / m (EN 755-9) |
| Twist Tolerance | ±0.5° / m | ±0.3° / m |
| Surface Finish | Mill finish, matte | Polished, brushed, anodized |
| Heat Treatment | T5 (air quench), T6 (water quench) | T6511 (stretcher + stress relieve) |
| Standard Lengths | 3 m, 4 m, 6 m, random 2–6 m | Cut-to-length ±2 mm |
The undisputed center of China's aluminum extrusion industry — over 1,200 extrusion factories in the Foshan-Nanhai area alone. Advantages: massive die shops (die costing $200–500 vs $800–1,500 in EU/US), 1,000-ton to 5,000-ton presses, and extreme competition that drives price down. Good for standard architectural and industrial profiles in 6063 T5. MOQ: 500–1,000 kg per profile. Lead time: 3–7 days die, 10–20 days extrusion.
Raw material advantage — home to China's largest primary aluminum smelters. Factories here get billets at near-smelter cost, typically $100–200/ton cheaper than Guangdong. Used extensively for heavy-duty profiles over 4 mm wall. Great for large-volume, cost-sensitive industrial extrusions (heat sinks, solar frames, scaffolding). MOQ: 1–3 tons per profile. Quality: generally OK for industrial but not architectural grade.
Premium quality hub serving foreign OEMs. Factories here often have ISO 9001, IATF 16949 (automotive), and AS9100 (aerospace). Precision T6511 extrusions for automation and machinery. Die costs higher ($500–1,000) but better tolerance control. Surface finish suitable for visible anodized end products. Lead time: 5–10 days die, 15–25 days extrusion.
Specialist in thin-wall precision extrusion (0.6–1.5 mm wall). Used in electronics, LED lighting channels, and display frames. Companies like Xingfa, Jianmei, and Asia Alum operate here. If you need a complex thin-wall profile that looks good after anodizing, this region's die-making skills are unmatched.
Money-saving tip: Design your profile with uniform wall thickness around the cross-section. Each change in wall thickness creates differential cooling and stress — leading to twist that requires additional straightening. A profile with 2 mm uniform walls costs about 15–20% less per meter to extrude than a variable-wall design with 1.5–3.0 mm sections. Die longevity also improves by 2–3x.
The extrusion die is your single biggest cost lever. A poorly designed die = time-wasting trial runs, excessive wear, and out-of-tolerance profiles. Include die flow analysis (FE simulation) in your budget — for complex profiles, it's a $200–500 investment that saves $2,000–5,000 in rework. When engaging a new supplier, ask to see their die flow simulation samples. Run real trials before mass production.
Mill finish profiles can exhibit die lines (runner marks), hot cracking, or pickup galling. These defects become especially visible after anodizing. Always request sample sections from the front, middle, and back of a full-length production run — front-of-extrusion samples are always cleaner because the die is fresh. We've seen buyers approve a 300 mm front-end sample, only to receive 6 m profiles with die lines on 80% of the length.
For window/door profiles requiring thermal insulation, Chinese factories offer PU foam injected thermal breaks. But quality varies dramatically — some factories skimp on the polyurethane density (should be 40–60 kg/m³ in the bridge gap) or use low-adhesion primer, causing delamination within months. Ask for pull-out test certificates per EN 14024: the polyamide strip must withstand 55–75 N per linear mm.
| Cost Component | % of Total | Notes |
|---|---|---|
| Aluminum billet (6063) | 50–60% | LME + premium $300–500/ton. Accounts for material and alloying elements |
| Extrusion processing fee | 25–35% | Varies by profile complexity, wall thickness, and press size. Ranges $500–1,500/ton |
| Die fabrication | 5–10% | Flat die $200–600, solid die $400–1,000. Amortized over production volume |
| Heat treatment (aging) | 3–5% | T5 cheaper (fan cooling), T6 requires aging oven at $50–150/ton |
| Packaging | 3–8% | Wooden crates, foam/paper interleaving. Export packaging adds 3–5% |
| Quality inspection | 2–5% | Hardness, dimensional, chemical analysis reports |
Typical total: $2,500–4,500/ton FOB for 6063 T5, $3,000–5,500/ton for 6061 T6. Die cost per piece added separately.
For 6063 alloy on a standard press: 1.0 mm minimum wall. For precision heavy-press profiles: 0.6 mm achievable with good die design. Thinner walls require higher billet temperature and faster ram speed, increasing die wear and risk of tearing. Thin-wall profiles also need more careful cooling/quench control to avoid distortion.
Best practice: start with GB/T 5237 (China national standard for architectural aluminum profiles) as the baseline, then selectively tighten only the critical dimensions. Over-specifying tight tolerances on every dimension increases rejection rates and cost unnecessarily. Mark critical dimensions on your drawing with a triangle symbol (Δ) or note — Chinese shops will prioritize those. Non-critical dimensions should stay at ±0.5 mm.
Die lines (extrusion streaks) appear as the die wears. For runs over 2,000 kg, schedule in-process die polishing/maintenance every 1,000–2,000 kg. Higher-grade die steel (H13 vs H11) extends the interval. Better factories also apply nitriding treatment on the die surface (gas or plasma nitriding) to increase hardness and delay die line onset.
Standard: 6 m (length of aging ovens). Some factories have 8 m or 14 m ovens for extra-long profiles. For 8 m+ profiles, check if the factory has long-aging oven capacity — not all do. Extra-long profiles also require special trucking (which is expensive for export — 6 m containers are standard, 8 m+ requires special containers).
Yes, but 6061 T6 is harder to extrude than 6063 because it has lower flowability at extrusion temperature (Mg₂Si and CuAl₂ precipitates). Expect higher die cost, slower production speed, and tighter process control. Most Chinese factories quote 15–25% higher processing fee for 6061 vs 6063. For automotive and aerospace applications, specify IATF 16949 or AS9100 certified suppliers.