Why are 1060 and 3003 alloys often used in aluminum discs for kitchenware? What are the differences in material properties between different parts?

HW-A. Introduction: The Core Role of Aluminum Discs for Cookware

aluminum disc alloys for cookware for cookware serve as the core base material for stamping-formed cookware (woks, stockpots, frying pans, etc.). Their alloy selection directly determines the thermal conductivity uniformity, forming difficulty, service life, and safety performance of cookware. Currently, 1060 (Series 1 pure aluminum) and 3003 (Series 3 aluminum-manganese alloy) account for over 90% of the market share as mainstream options for this material. Additionally, the material difference between pot bottoms and bodies is a refined design based on the principle of “functional zone adaptation,” which together forms the technical system of aluminum base materials for cookware.

HW-B. Core Reasons for Choosing 1060 and 3003 Alloys for Cookware Aluminum Discs

The properties of 1060 and 3003 alloys are highly compatible with the manufacturing requirements of cookware, and they offer a better balance of “performance-cost-process” compared to other aluminum alloys (e.g., 5052, 6061). The specific reasons can be analyzed from three aspects:

(A) Inherent Alloy Properties: Aligning with Core Cookware Requirements

(B) Compatibility of the Aluminum Disc Material with Cookware Manufacturing Processes

1. Forming Process Compatibility:

• • As a material for these cookware discs, 1060’s high elongation (δ10≥30%) enables “one-time stretch forming,” suitable for complex curved surfaces of pot bodies (e.g., a wok with diameter 32cm has a pot wall stretch height >8cm). Furthermore, it exhibits no obvious springback after forming, with dimensional accuracy up to ±0.1mm;

• • For 3003, its balanced strength and ductility (δ10≥20%) make it ideal for the “stamping thickening” process of pot bottoms (e.g., stamping a 2mm aluminum disc into a 3mm pot bottom to enhance load-bearing capacity). Notably, it maintains shape stability without annealing after stamping—unlike 1060, which requires annealing at 300℃ for 1h to eliminate internal stress after stretching.

2. Post-Processing Adaptability:

• • The oxide film (Al₂O₃) on the surface of 1060-based cookware discs is uniform and easy to color, making it suitable for anodized colored pot bodies (e.g., matte black, champagne gold) with a film thickness of 10-15μm (as required by GB/T 8013.1);

• • For 3003-based cookware discs, their surface is easy to weld or composite with other materials (e.g., stainless steel magnetic layer, copper thermal layer). Moreover, the corrosion resistance at welded joints does not significantly decrease, meeting the induction cooker compatibility requirement of “aluminum-steel composite” pot bottoms.

(C) Logic for Excluding Other Alloys from Cookware Disc Applications

Why are alloys like 5052 (Series 5 Al-Mg alloy) and 6061 (Series 6 Al-Mg-Si alloy) not chosen for this cookware material? The core lies in “performance surplus” or “functional mismatch”:

• 5052: Its tensile strength (σb=230MPa) is much higher than that of 1060/3003, but its low elongation (δ10≤25%) causes cracking during stretching, making it unable to form complex pot bodies. Additionally, its high magnesium content (2.2-2.8%) leads to Mg₂Si precipitation at temperatures >180℃, resulting in uneven thermal conductivity;

• 6061: It has high hardness (HB≥95) but low thermal conductivity (λ=160W/(m·K)), only 69.6% of that of 1060, easily causing “local hot spots” during cooking (e.g., overheating at the pot bottom center and low temperature at the edges). Moreover, its poor ductility after age hardening makes it unsuitable for stamping;

• 1100 (Series 1 pure aluminum): Its purity (Al≥99.0%) is lower than 1060, and its thermal conductivity (λ=223W/(m·K)) is slightly lower. Its corrosion resistance (white rust appears after 300h salt spray test) is inferior to 3003, so it is only used in low-end cookware (e.g., disposable aluminum pots) and cannot serve as a mainstream cookware aluminum disc material.

HW-C. Material Differences Between Different Cookware Parts: Functional Zone Application of Cookware Aluminum Discs

Pot bottoms and bodies face significantly different working conditions (temperature, stress, corrosion environment), so there are obvious differences in the selection, thickness design, and process treatment of the aluminum disc material for cookware. The specific comparisons are as follows:

(A) Core Difference: Functional Requirements Determine Material Selection for Cookware Discs

(B) Material Details: Thickness and Process Enhancement of Cookware Aluminum Discs

1. Pot Bottom Material Design:

• • Base material: 3003-based cookware discs with a thickness of 2-3mm (50-100% thicker than the pot body). Reasons: ① Thickening reduces heat flux density (Q=λ×ΔT/δ; increased δ decreases local temperature gradient), avoiding “burning”; ② Enhances rigidity to prevent high-temperature deformation (e.g., pot bottom warping);

• • Composite enhancement: Mid-to-high-end cookware adopts a composite structure of “3003-based cookware discs + magnetic layer” (e.g., “3003 (2mm) + 430 stainless steel (0.5mm)”) to solve the non-magnetic issue of pure aluminum (incompatible with induction cookers). The stainless steel layer improves wear resistance (430 stainless steel has a hardness of HB≥170, twice that of 3003);

• • Surface treatment: Pot bottoms are usually sandblasted (Ra=1.6-3.2μm) to increase friction with stoves (preventing sliding) and avoid non-stick coating peeling at high temperatures (non-stick coatings tend to decompose when pot bottom temperature exceeds 260℃).

2. Pot Body Material Design:

• • Base material: 1060-based cookware discs with a thickness of 1-1.5mm. Advantages: ① Lightweight (15-20% lighter than 3003 for the same-sized pot body), providing a more comfortable hand feel; ② High ductility supports “deep drawing” (e.g., stockpot depth >15cm) without wrinkles after forming;

• • Surface treatment: Anodic oxidation is the main process (70% application rate) with an oxide film thickness of 8-12μm, featuring: ① Scratch resistance (HB≥3H, withstands light scratches from wok spatulas); ② Stain resistance (closed surface pores, preventing oil residue). For instance, some high-end cookware uses ceramic coatings (based on 1060-based cookware discs) with a thickness of 20-30μm to improve high-temperature resistance (withstanding short-term dry burning at 400℃);

• • Structural adaptation: The connection area between the pot body and bottom (e.g., “pot neck”) adopts “1060-based + local 3003-based cookware disc splicing.” The reason is that the connection area needs to withstand heat and stress conducted from the pot bottom, and the strength of 3003 prevents cracking (TIG welding is used for splicing, with weld tensile strength ≥100MPa).

(C) Practical Cases: Application of Cookware Aluminum Discs by Mainstream Brands

1. Supor “Red Hot Spot” Wok:

• • Pot bottom: 3003-based cookware discs (2.5mm thick) + 430 stainless steel magnetic layer (0.4mm thick). The composite process is “hot rolling lamination” (lamination strength ≥50N/cm), solving induction cooker compatibility and high-temperature deformation issues;

• • Pot body: 1060-based cookware discs (1.2mm thick) with “anodic oxidation + nano-ceramic coating” on the surface. Its elongation reaches 32%, enabling “one-piece stretch forming” (seamless pot wall).

2. ZWILLING “Motion” Stockpot:

• • Pot bottom: 3003-based cookware discs (3mm thick) + pure copper core (0.8mm thick, λ=401W/(m·K)). The copper core improves thermal conductivity (twice that of pure 3003 pot bottoms), suitable for rapid soup boiling;

• • Pot body: 1060-based cookware discs (1.5mm thick) with “brushed anodic oxidation” on the surface (Ra=0.8μm), enhancing appearance texture and fingerprint resistance.

HW-D. Industry Trends: Upgrade of Cookware Aluminum Discs and Application Expansion of Composite Materials

With the refinement of cookware functional requirements (e.g., low-sugar cooking, induction compatibility, lightweight design), the application of cookware aluminum discs (based on 1060 and 3003) is also upgrading, with the main directions including:

1. Alloy Composition Optimization:

• • “Ultra-low impurity” version of 1060-based cookware discs (Fe≤0.15%, Si≤0.10%) with thermal conductivity increased to 235W/(m·K), suitable for high-end precision cookware (e.g., baby food pots);

• • “Micro-alloyed” 3003-based cookware discs (adding 0.1-0.2% Zr) with high-temperature strength (σb≥80MPa at 300℃) 15% higher than ordinary 3003, suitable for woks used for long-term open-flame cooking.

2. Multi-layer Composite Structure:

• • Four-layer structure: “1060-based cookware discs (pot body) + 3003-based cookware discs (transition layer) + 430 stainless steel (outer pot bottom) + copper core (center).” It balances thermal conductivity, corrosion resistance, magnetism, and appearance, and has been applied in high-end cookware priced at over 10,000 yuan.

3. Eco-friendly Process Adaptation:

• • Both 1060 and 3003-based cookware discs comply with EU RoHS 2.0 and U.S. FDA food contact standards (FDA 21 CFR 175.300), and can be 100% recycled (the performance of recycled aluminum is only 5-8% lower than primary aluminum), aligning with the “green cookware” trend.

HW-E. Conclusion

The selection of 1060 and 3003 for cookware aluminum discs is essentially a balance of “alloy properties – cookware requirements – process cost”: 1060-based discs adapt to the forming and appearance requirements of pot bodies with high ductility and uniform thermal conductivity, while 3003-based discs adapt to the high-temperature and stress conditions of pot bottoms with high strength and corrosion resistance. By contrast, the material difference between pot bottoms and bodies is a refined application of these cookware discs based on “functional zoning.” Through alloy selection, thickness adjustment, and composite enhancement, the optimal overall performance of cookware is achieved. In the future, with the advancement of composite materials and alloy optimization, 1060 and 3003 will remain the core alloy choices for cookware aluminum discs, while more upgraded solutions adapting to segmented scenarios will emerge.