I. Classification by Processing Technology

1. Hot-Dip Galvanized Steel (HDG)

Process: The steel sheet is immersed in molten zinc (450-460°C), resulting in a zinc layer thickness typically 50-200g/㎡.

Features: Uniform zinc layer, strong adhesion, and excellent corrosion resistance (suitable for outdoor applications).

Applications: Building roofs, highway guardrails, and photovoltaic mounting systems (e.g., West African pipe piles).

2. Electrogalvanized Steel (EG)

Process: Electrolytically deposits a zinc layer with a thickness of 5-30g/㎡ and a smooth surface.

Features: High precision (controllable zinc layer thickness), suitable for complex forming.

Applications: Appliance housings (e.g., air conditioner housings), precision instrument housings (requiring fingerprint resistance).

3. Alloyed Galvanized Steel (GA)

Process: Hot-dip galvanizing followed by heating to form an alloy layer (Fe-Zn).

Features: Anti-powdering, high-temperature resistance (200°C), and excellent weldability. Applications: Automotive chassis, battery pack casings (new energy sector).

II. Classification by zinc coating thickness

1. Standard zinc coating (50-120g/m2)

Standard: Complies with national standard GB/T 2518-2019, suitable for general corrosion environments.

Applications: Indoor equipment housings, building components in dry areas.

2. Thick zinc coating (≥200g/m2)

Standard: EU EN 10346, salt spray resistance ≥1000 hours.

Applications: Beach villas, chemical plants (such as those in West African mangroves).

3. Cut-edge protection zinc coating

Process: Cold-spray zinc (zinc content ≥99.9%) on cut edges, increasing thickness by 30-50μm.

Applications: Pipe piles, steel structure joints (to prevent cut-edge corrosion).

III. Classification by application

1. Galvanized sheet for building structures

Requirements: High load-bearing capacity, weather resistance (C5 corrosion environment). Solution: 200g/㎡ zinc coating + cold-spray zinc cutting treatment, ISO 12944 certified.

2. Galvanized Sheet for Automotive Manufacturing

Requirement: Balance of lightweight and safety (e.g., new energy battery packs).

Solution: High-strength galvanized sheet (550MPa grade), achieving a 15% weight reduction while meeting crash test requirements.

3. Galvanized Sheet for Reservoirs

Requirement: Water and chemical resistance (pH 5-9).

Solution: Epoxy resin coating on the zinc layer, passing a 240-hour neutral salt spray test.

4. Galvanized Sheet for Home Appliance Exteriors

Requirement: Fingerprint and scratch resistance (e.g., outdoor air conditioner housings).

Solution: Electrogalvanized sheet + anti-fingerprint coating, combined with pearl cotton for protection (refer to a Vietnamese case).

IV. Classification by Mechanical Properties

1. Standard-Strength Galvanized Sheet

Tensile Strength: 370-450MPa, suitable for non-load-bearing structures (e.g., decorative panels). 2. High-Strength Galvanized Sheet

Tensile strength: ≥550 MPa, suitable for load-bearing structures (such as automobile chassis and building trusses).

Example: In the West African pipe pile project, 35CrMo alloy galvanized sheet has a temperature resistance of 500°C and is certified for a 30-year lifespan.