Optimization of surface quality and forming performance of cold-rolled coil in home appliance manufacturing: analysis of key technologies and standards

Optimization of surface quality and forming performance of cold-rolled coil in home appliance manufacturing: analysis of key technologies and standards

Home appliances are not only functional carriers, but also an important part of modern home aesthetics. Its smooth and beautiful shell and smooth and precise shape largely rely on the quality of the core material-cold-rolled coil. Surface defects or forming cracks will directly lower the product grade and even cause user complaints. This article will explore in depth how to help improve the quality and efficiency of home appliance manufacturing by optimizing the surface quality and forming performance of cold-rolled coil.

 

Ⅰ. Surface quality: the cornerstone of home appliance "appearance" and durability

The surface of cold-rolled coil is the "face" of home appliances, and its quality is crucial:

Zero tolerance defects: Defects such as roller marks, scratches, and oxidation spots will be magnified after home appliance surface treatment technology (such as spraying and laminating), becoming a hard flaw that cannot be covered up.

Consistency is king: Uniform surface roughness is the prerequisite for ensuring uniform spraying and consistent gloss, which directly affects the texture and brand image of the final product.

Corrosion resistance guarantee: Excellent surface condition is the basis for subsequent galvanizing, galvanizing and other surface treatment technologies to achieve the best anti-rust effect, ensuring the long-term service life of home appliances in humid environments.

Optimization strategy:

Precision rolling and cleaning: Use high-precision rollers, cooperate with efficient rolling oil filtration and strip cleaning systems to reduce defects from the source.

Advanced surface treatment: Apply environmentally friendly and corrosion-resistant coating technology (such as chromium-free passivation, high corrosion-resistant alloy coating) to enhance the protection of the substrate.

Online intelligent detection: Deploy online surface quality detection systems (such as machine vision), monitor and sort in real time to ensure "zero defects" in factory panels.

Ⅱ. Forming performance: The core ability to shape the "beauty of form" of home appliances

The design of home appliance shells is becoming increasingly complex, and the formability of cold-rolled steel is strictly required:

Challenge the limit: The complex curved surface of refrigerator door panels, the deep drawing of washing machine inner barrels, and the precise flanging of range hoods all require materials to have excellent plastic deformation capabilities.

Precise springback control: Small springback after forming, ensuring part dimensional accuracy and reducing subsequent correction processes.

Anti-cracking and uniform thinning: Resist cracking in high-strain areas while maintaining uniform wall thickness to ensure structural strength and appearance consistency.

Optimization strategy:

Composition and organization control: Optimize steel composition (such as low carbon, micro-alloying) and annealing process to obtain fine and uniform ferrite grains and improve plasticity indicators (n value, r value).

Application of advanced high-strength steel: Reasonable use of bake-hardened steel (BH steel) and high-strength low-alloy steel (HSLA) in structural parts to achieve thinning and weight reduction without sacrificing formability and strength.

Precise forming simulation: Use CAE software to accurately simulate the stamping process, predict cracking and wrinkling risks, and guide mold design and material selection.

Ⅲ. High standards lead: the evolution and requirements of home appliance steel standards

Major home appliance brands and industry associations at home and abroad have formulated strict home appliance steel standards (such as national standard GB/T, European standard EN, American standard ASTM and many corporate standards), and put forward clear requirements for cold-rolled coils:

Surface grade: usually requires high-grade finishing surface (such as FB, FC), strictly limits the type, size and number of defects.

Mechanical properties: clearly specify the range of yield strength, tensile strength, elongation, n value, r value, etc. to ensure forming stability.

Coating performance: There are detailed specifications for coating type, thickness, adhesion, corrosion resistance (such as salt spray test hours).

Dimensional accuracy: Strict requirements for thickness and width tolerances, especially for precision cold-rolled plates.

Trend: Standards continue to upgrade, with more emphasis on environmental protection (chromium-free, low VOC), high strength thinning, better formability and surface compatibility.

Ⅳ. Precision cold-rolled sheet: the inevitable choice for high-end home appliance manufacturing

Facing the demand for extreme appearance and complex shapes of high-end home appliances, precision cold-rolled sheet has become the core solution:

Ultra-thin and ultra-flat: The thickness tolerance is controlled within ±0.02mm, and the flatness is excellent, laying the foundation for precision stamping and stable spraying.

Excellent micro-surface: The surface roughness (Ra value) is precisely and evenly controlled to meet the requirements of special surface effects such as high-end brushed, mirror, AG anti-glare, etc.

Highly uniform performance: The mechanical properties and forming properties are highly stable in the length and width of the entire roll, ensuring the consistency of large-scale production.

Conclusion: Collaborative optimization drives the upgrade of home appliance manufacturing

The value of cold-rolled coil in home appliance manufacturing is far more than basic materials. Its surface quality is the guardian of brand image and product life, and its forming performance is the key to achieve complex design and efficient production. Deeply understanding and meeting the constantly upgraded standards for home appliance steel, and actively applying advanced surface treatment technology and precision cold-rolled sheet are the only way for home appliance manufacturers to improve product competitiveness, reduce costs and increase efficiency. Through close cooperation between material suppliers and home appliance manufacturers, continuous in-depth research on "surface" and "forming" can forge high-quality home appliances that are both beautiful inside and out and lead the market.

Case perspective: A high-end refrigerator brand uses precision cold-rolled galvanized steel sheets with specific r-values to successfully achieve one-time stamping of the door body with a large arc. After surface spraying, the gloss uniformity is increased by 20%, and the customer complaint rate is significantly reduced.

Data insights: Industry research shows that optimizing the surface roughness parameters of cold-rolled coils can save about 8% of the spraying materials for home appliance panels, while improving the coating adhesion level by more than 1 level.

Through material innovation and process improvement, cold-rolled coils are continuously driving home appliance products to leap towards higher quality, better design, and stronger performance.