Galvanized plate is a metallic material featuring a zinc coating applied to the surface of steel plate. This galvanization process significantly enhances the plate's corrosion resistance and service life. The core of the galvanized plate consists of an iron substrate, while the external zinc layer plays a crucial role in protecting the internal iron material from corrosion. This material finds extensive application across multiple sectors, including construction, household appliances, automotive and marine manufacturing, container production, and the electromechanical industry.

 

1. Definition and Fundamental Principles of galvanized plate

Galvanized plate refers to steel plates coated with a layer of metallic zinc. This coating leverages zinc's chemical properties to prevent rust and corrosion of the underlying plate. While steel possesses high strength, it exhibits poor corrosion resistance. Exposure to humid, acidic, alkaline, or saline environments readily induces oxidation and rusting. The galvanized layer acts as a protective barrier, effectively delaying the corrosion process.

Zinc rapidly reacts with oxygen in the air to form a dense zinc oxide film. This film not only prevents moisture from directly contacting the steel substrate but also functions as a ‘sacrificial anode’ when the coating is damaged. That is, zinc undergoes electrochemical corrosion preferentially, thereby shielding the underlying steel from harm. This mechanism endows galvanized plates with enduring and stable rust-proofing properties.

 

2. Manufacturing Processes for galvanized plates

(1) Hot-Dip Galvanizing Process

Hot-dip galvanizing is currently the most prevalent galvanizing method. Its process sequence comprises degreasing, pickling, pre-coating, drying, zinc immersion, and cooling. When steel sheets are immersed in molten zinc at high temperatures, an iron-zinc alloy layer and a pure zinc layer form on the surface.

- Characteristics: Thick coating, strong adhesion, outstanding corrosion resistance.

- Applications: Commonly used in building steel structures, transmission towers, vehicle chassis components, bridge components, etc.

(2) Electrogalvanizing Process

Electrogalvanizing employs electrolysis to deposit zinc ions onto steel surfaces, forming a uniform thin layer.

- Characteristics: Thin yet uniform coating with high surface finish, suitable for products requiring superior aesthetics.

- Applications: Appliance casings, electronic equipment housings, precision components, etc.

(3) Alloy Galvanizing and Novel Processes

In recent years, evolving demands have spurred the development of new techniques such as aluminium-zinc alloy coatings and zinc-aluminium-magnesium alloy coatings. Compared to traditional single-layer zinc coatings, these alloy coatings offer superior corrosion resistance and extended service life, particularly suited to harsh environments like acid rain and marine atmospheres.

 

3. Key Advantages of galvanized Sheets

Galvanized plates possess not only excellent properties but also numerous advantages, enabling their widespread application across multiple sectors.

(1) Robust Durability:

The galvanized coating forms a tightly bonded layer with the steel substrate, exhibiting high impact resistance. It remains intact even when subjected to knocks during transportation or construction, resisting peeling or damage. This robustness makes Galvanized plates ideal for manufacturing mechanical components and industrial equipment.

(2) Moisture Resistance and Durability:

The zinc coating effectively isolates the steel from air and moisture, preventing direct environmental contact. This eliminates issues like mould growth or dampness, ensuring stable product performance. Whether in humid coastal regions or rainy environments, galvanized plate maintains consistent corrosion resistance.

(3) High Aesthetic Appeal:

Galvanized plates feature a smooth surface with uniform colouration. They can undergo various treatments such as spray painting or plastic coating to meet diverse colour and texture requirements, enhancing product aesthetics. This advantage has led to their widespread application in building exteriors, appliance casings, and similar fields.

(4) Expedited Installation:

Galvanized plates require minimal time and labour during installation. They can be put into service immediately after fitting without on-site painting or additional anti-corrosion treatments. The straightforward installation process significantly boosts construction efficiency, making it particularly suitable for large-scale projects.

(5) Cost-Effectiveness:

Compared to other corrosion-resistant metals, galvanized steel sheets offer lower costs while maintaining stable performance, meeting the demands of mass production. This advantage has led to galvanized plate's widespread adoption across multiple sectors.

(6) High Formability:

galvanized plate metal can be stamped, rolled, or bent to any shape as required, accommodating diverse specifications. This property grants exceptional flexibility in fabricating complex structural components.

(7) Environmental sustainability and energy efficiency:

Galvanization represents an economical and effective rust prevention method, accounting for approximately half of global zinc production. Zinc is 100% recyclable, and the EU REACH regulation certifies it as free from harmful substance emissions. This advantage has led to increased adoption of galvanized plates amidst today's increasingly stringent environmental requirements.

 

4. Application Areas of Galvanized Plates

Owing to their superior properties and extensive applicability, galvanized steel plates find widespread use across multiple sectors including construction, furniture, electrical appliances, and machinery.

(1) Construction Industry:

Galvanized plates are most extensively employed in building applications such as roofing tiles, external wall cladding, door and window frames, rainwater drainage systems, and steel structural supports. It effectively withstands weathering, prolonging building longevity. Galvanized plate is virtually indispensable in steel-framed industrial buildings, storage facilities, and residential construction.

(2) Domestic Appliances:

Galvanized plates are extensively used in household appliances including refrigerators, washing machines, air conditioners, microwave ovens, bread makers, photocopiers, vending machines, electric fans, and vacuum cleaners. Galvanized plate not only enhances aesthetic appeal but also prevents corrosion caused by moisture or grease, thereby extending the lifespan of appliances.

(3) Furniture Industry:

Within the furniture sector, galvanized plates are primarily used for lampshades, wardrobes, tables, bookshelves, and medical equipment. Combining robustness with aesthetic appeal, galvanized plate has become a crucial material in furniture manufacturing.

(4) Transportation

Galvanized plates are extensively employed in vehicle bodies, lorry cargo compartments, shipping containers, ship bulkheads, and motorway crash barriers. Their corrosion resistance and impact strength ensure the safety and durability of transport vehicles during prolonged use.

(5) Mechanical and Industrial Equipment

In mechanical engineering, galvanized plate is employed for lift casings, ventilation ducts, machine tool enclosures, and warehouse shelving. It effectively withstands moisture, dust, and corrosive substances in complex workshop environments.

(6) Other Applications

Galvanized plate also finds use in musical instrument casings, photographic equipment, everyday hardware products, and public facilities (such as litter bins and advertising hoardings), achieving comprehensive coverage from industrial to domestic applications.

 

5. Development Trends of Galvanized Plates

(1) Enhanced Performance: Future galvanized  plates will evolve towards higher strength and corrosion resistance. For instance, zinc-aluminium-magnesium alloy-coated steel has emerged as a new solution for combating marine atmospheric corrosion.

(2) Environmental Sustainability: With increasingly stringent environmental regulations, green processes are progressively replacing traditional chromium- and lead-containing methods. New technologies like chromium-free passivation and eco-friendly coatings are becoming widespread.

(3) Smart Manufacturing: Automated, digital production lines enhance efficiency and stability in galvanized plate manufacturing, delivering greater dimensional accuracy and superior surface quality.

(4) Expanded Applications: Beyond traditional sectors, demand for galvanized plates is growing in emerging industries such as renewable energy, rail transport, smart homes, and modern agricultural facilities.

 

With core advantages including corrosion resistance, durability, processing flexibility, low cost, and environmental sustainability, galvanized plate has become an indispensable metal material in modern industry and daily life. Whether in urban skyscrapers, transport infrastructure, or household appliances and furniture, galvanized plate quietly safeguards product stability and longevity. Through continuous technological innovation and expanding application domains, galvanized steel plate will play an increasingly vital role in the future, emerging as a key driver for industrial upgrading and green manufacturing.