Aluminum circle for cooker

Selecting the correct alloy is critical for performance. 1050 and 1100 alloys are the most common for basic cookware due to their 99% purity, excellent thermal conductivity, and high ductility, making them ideal for deep drawing. For high-end or pressure cookers, 3003 alloy is preferred because the addition of manganese increases mechanical strength by 20% and provides superior corrosion resistance.

To prevent 'orange peel' effects or cracking during production, buyers must specify the grain size (typically 25-40 microns) and elongation rate (≥30%). Ensure the temper is set to 'O' (annealed) to provide the necessary softness for complex shaping. Additionally, the thickness tolerance should be strictly controlled within ±0.02mm to ensure uniform heat distribution in the final product.

The surface must be free of oil stains, scratches, and oxidation. For cookers intended for non-stick coating, a fine-sanded or brushed finish is often required to increase the surface tension and adhesion of the PTFE or ceramic layer. Always request a tension test report to confirm the surface is chemically clean and ready for secondary processing.

Since the product comes into contact with food, it must comply with FDA (USA), LFGB (Germany), or EU 1935/2004 regulations. Ensure the supplier provides a Material Test Report (MTR) and a Heavy Metal Content Analysis to prove the aluminum is free from harmful impurities like lead or cadmium.

Aluminum is highly sensitive to moisture. You must require the supplier to use seaworthy packaging, which includes plastic film wrapping, desiccant silica gel packets, and waterproof kraft paper, all secured on fumigated wooden pallets. For long-distance shipping, vacuum packaging is the gold standard to prevent 'white rust' caused by condensation.

Pricing in this industry is usually tied to the LME (London Metal Exchange) aluminum price plus a fabrication fee. Negotiate a fixed fabrication fee while allowing the base metal price to fluctuate with the market. For orders exceeding 5 tons, aim for a 3-5% discount on the fabrication cost, and always clarify if the price includes export tax rebates.

Prioritize Audited Suppliers who have undergone third-party inspections by SGS, Bureau Veritas, or TÜV Rheinland. Check their export history to your specific region and request a video factory audit to inspect their rolling and punching equipment. This ensures the supplier is a direct manufacturer rather than a middleman, which reduces costs and lead times.

Use Secured Trading services provided by Made-in-China.com to ensure funds are only released upon proof of shipment. For the first order, insist on a Third-Party Pre-shipment Inspection (PSI). If the thickness or hardness does not meet the agreed-upon Proforma Invoice (PI) specs, the inspection report serves as your primary evidence for a refund or replacement claim.