แผ่นอลูมิเนียมคอมโพสิตสำหรับเครื่องครัว: การออกแบบกระบวนการกลิ้งและการตรวจสอบประสิทธิภาพเพื่อขจัดฟองอากาศและการหลุดร่อนระหว่างชั้น

1. การแนะนำ

Composite aluminum discs for kitchenware are core substrates for high-end cookware (เช่น, กระทะทอดแบบไม่ติด, หม้อซุปบุสแตนเลส, และกระทะที่เข้ากันได้กับการเหนี่ยวนำ), requiring three non-negotiable core performances to meet daily cooking demands:

1. Thermal conductivity uniformity: Temperature deviation across the disc surface must be ≤5% to avoid local overheating (เช่น, burnt egg edges in a frying pan) — this is achieved via the outer 3003 โลหะผสม, which has a thermal conductivity of 200W/(ม·เค), 30% สูงกว่าอลูมิเนียมบริสุทธิ์;

2. Structural strength: Yield strength ≥180MPa to resist deformation during stamping (เช่น, forming a 10cm-deep soup pot) and long-term use — the middle 5052 โลหะผสม (Al-Mg 系) provides this strength, ที่มีเนื้อหา Mg ของ 2.5% enhancing corrosion resistance (critical for acidic foods like tomatoes);

3. Thermal shock resistance: No cracking after 20+ cycles between -20℃ (refrigerated storage) and 260℃ (oven baking) — a key requirement for cookware that transitions between cold storage and stovetop heating.

The typical composite structure is 3003/5052/3003, with diameters ranging from 100mm (small saucepans) to 300mm (large woks) and total thicknesses of 3-8mm (thicker for soup pots, thinner for frying pans).

A critical quality bottleneck is interlayer defects: Bubbles with diameter ≥0.5mm cause uneven heating (temperature differences up to 50℃), while delamination leads to cookware deformation or even detachment of the non-stick coating. ตาม 2024 data from the China Kitchenware Association, 32% of composite aluminum disc scrap stems from interlayer issues, with an average single-batch loss of ≥800,000 yuan (เช่น, a 5,000-piece batch of 24cm pan discs due to bubbles).

Traditional rolling processes fail to address these defects due to mismatched parameters (เช่น, insufficient temperature for atomic diffusion, uneven pressure leaving air pockets). ดังนั้น, precise synergistic control of rolling temperature, ความดัน, and reduction rate is essential to achieve “zero interlayer bubbles and delamination”.

2. Causes of Interlayer Defects

Interlayer defects arise from the combined effects of material inherent properties and process fluctuations, with clear mechanisms for each:

(1) Material-Related Barriers

ที่ 3003 และ 5052 alloys in composite discs have inherent property differences that hinder interface bonding, ตามรายละเอียดในตารางด้านล่าง:

(2) Process-Related Defects

Even with well-matched materials, improper rolling parameters directly generate defects:

• Temperature mismatch:

• • Below 380℃: Atomic kinetic energy is too low — Mg atoms in 5052 can only diffuse 0.1-0.2μm, failing to cross the oxide layer. This leaves “physical contact gaps” (5-10ไมโครเมตร) between layers, which trap air and form bubbles.

• • Above 500℃: มินอิน 3003 precipitates as Al₆Mn hard particles (1-3ไมโครเมตร), which scratch the 5052 layer during rolling. high temperature accelerates oxidation, thickening the Al₂O₃ layer to >10นาโนเมตร, worsening bonding.

• Pressure issues:

• • Below 10MPa: Insufficient force to expel interlayer air (initial thickness 5-10μm). The compressed air forms bubbles (0.3-1เส้นผ่านศูนย์กลางมม), and the interface contact area is only 60-70%, leading to weak bonding.

• • Pressure deviation >5MPa: Due to uneven roll stress, the disc edge (แรงดันสูง) overflows metal, while the center (low pressure) retains air — a common defect in large-diameter discs (≥250mm).

• Unreasonable reduction rate:

• • Total reduction rate <40%: Metal deformation is insufficient to flatten interface irregularities (3-5ไมโครเมตร), leaving micro-bubbles that expand during cookware heating.

• • Single-pass reduction rate >30%: Metal flows too fast (>100มิลลิเมตร/วินาที), entraining air into the interface. Excessive deformation stress also creates “รอยแตกร้าว” (1-2ไมโครเมตร) between layers, which develop into delamination after cooling.

3. Synergistic Regulation Strategy

To address the above causes, a synergistic strategy is developed for 3003/5052/3003 composite discs (taking φ200mm, target thickness 6mm as an example), มุ่งเน้นไปที่ “temperature as the foundation, pressure as the key, and reduction rate as the guarantee”.

(3.1) Material Properties for Reference

Understanding layer-specific functions and requirements guides parameter design:

(3.2) Core Rolling Parameters (3003/5052/3003, φ200mm, Target Thickness 6mm)

Parameters are divided into three stages to match the bonding process:

(3.3) Single-Pass Reduction Rate Allocation

A 5-pass rolling schedule balances deformation and bonding, avoiding excessive stress:

(3.4) Traditional vs. Optimized Processes

The optimized process addresses key flaws in traditional methods, with measurable defect reductions:

4. Auxiliary Process Optimization

Core parameters alone are insufficient — auxiliary processes eliminate hidden defects and stabilize quality:

5. Performance Verification

To validate the optimized process, comprehensive testing was conducted on 3003/5052/3003 composite discs (φ200mm, thickness 6mm) by a national-level aluminum processing laboratory:

(5.1) Interlayer Quality Test

Tests followed GB/T 3880.3-2022 (aluminum composite foil standards), with results below:

(5.2) Kitchenware Performance Test

Discs were formed into 24cm non-stick frying pans and 20cm soup pots for practical performance testing:

• Thermal conductivity uniformity:

• • Test conditions: Induction cooker (2000ว), heating to 200℃, 5 test points (ศูนย์ + 4 ขอบ, 50mm apart).

• • ผลลัพธ์: Temperature difference reduced from 45℃ (แบบดั้งเดิม) to 12℃ (optimized) — meets the “no local burnt” requirement for frying pans.

• Thermal shock resistance:

• • Test conditions: 20 cycles of -20℃ (freezer, 2ชม.) → 260℃ (oven, 30นาที), rapid transfer (≤30s).

• • ผลลัพธ์: Optimized discs showed no delamination or cracking; traditional discs delaminated at the 8th cycle (edge separation ≥2mm).

• ความสามารถในการขึ้นรูป:

• • Test conditions: Stamping into 10cm-deep soup pots (pressure 0.5MPa, temperature 180℃).

• • ผลลัพธ์: Forming qualification rate increased from 78% (แบบดั้งเดิม, ข้อบกพร่อง: แคร็ก, การแยกส่วน) ถึง 99% (optimized, ไม่มีข้อบกพร่อง).

6. กรณีการใช้งานอุตสาหกรรม

A leading Chinese kitchenware enterprise (annual output: 10 million sets, main products: กระทะไม่ติด) faced severe quality issues in 2023:

• ปัญหา: 8.5% of frying pans were recalled due to interlayer bubbles (customer complaints: “food burns on one side”); a single batch of 5,000 φ24cm discs was scrapped, causing a 2-day production line shutdown and 1.2 million yuan in losses.

• Optimization Measures: Adopted the synergistic strategy above, รวมทั้ง:

1. 1. Adjusting preheating temperature from 390℃ to 430℃, extending holding time to 35min;

1. 2. Installing a zoned hydraulic system (edge pressure +4MPa) to solve center bubbles;

1. 3. Implementing 1200-grit polishing and low-temperature annealing (290℃, 2.5ชม.);

1. 4. Using CrN-coated rolls (Ra 0.08μm) to reduce indentation defects.

• ผลลัพธ์:

• • Bubble rate of composite discs: 6.8% → 0.05%;

• • Peel strength: 11.8MPa → 20.3MPa;

• • Customer complaints: 8.5% → <0.3%;

• • Annual loss reduction: 8 ล้านหยวน;

• • Thermal conductivity of pans: เพิ่มขึ้นโดย 15% (faster heating, energy saving ~10%).

7. ข้อสรุป & Outlook

(1) ข้อสรุปหลัก

The key to achieving “zero interlayer bubbles and delamination” สำหรับ composite aluminum discs สำหรับเครื่องครัว lies in synergistic control of three core parameters (อุณหภูมิ, ความดัน, reduction rate) plus auxiliary processes:

• อุณหภูมิ: 420-450℃ preheating + 400-430℃ rough rolling + 380-400℃ finish rolling — ensures sufficient atomic diffusion while avoiding oxidation and precipitation;

• ความดัน: 15-20MPa zoned pressure (edge +3-5MPa) — completely expels interlayer air and ensures uniform contact;

• Reduction rate: 50%-60% total rate + 16.7%-30% single-pass gradient allocation — balances deformation and stress;

• Auxiliary processes: การล้างไขมัน + ขัด + การป้องกันก๊าซเฉื่อย + annealing — eliminates hidden defects and stabilizes bonding.

This combination achieves bonding strength ≥18MPa, bubble rate ≤0.1%, and meets all kitchenware performance requirements.

(2) ทิศทางการพัฒนาในอนาคต

1. Intelligent parameter regulation:

• • Develop a BP neural network model that inputs real-time data (อุณหภูมิ, ความดัน, roll speed) and outputs defect probability. When the probability exceeds 5%, the system automatically adjusts parameters (เช่น, increases induction heating power if temperature drops, or adjusts hydraulic pressure if bubbles are detected via ultrasonic sensors). This will reduce reliance on manual operation and improve process stability to >99%.

2. New composite structures:

• • For heavy-duty cookware (เช่น, outdoor camping pots), develop 3003/6061/3003 composite discs (middle layer 6061 โลหะผสม: ความแข็งแรงของผลผลิต≥270MPa). Tailored parameters: preheating temperature 450-480℃ (matches 6061’s recrystallization temperature), rolling pressure 20-25MPa (compensates for higher strength), and single-pass reduction rate ≤25% (avoids cracking).

3. Eco-friendly processes:

• • Replace traditional alkaline degreasing with ultrasonic water-based degreasing (reduces chemical usage by 50%) and develop recyclable rolling oil (recycling rate ≥80%) to meet global environmental standards (เช่น, EU REACH).

The optimization of composite aluminum disc rolling processes not only improves kitchenware quality and reduces costs but also provides a technical reference for other composite metal materials (เช่น, aluminum-copper, aluminum-steel), driving innovation in the lightweight metal processing industry.