Galvanized steel sheet refers to welded steel sheet with a zinc layer formed on its surface through hot-dip galvanizing or electroplating processes. Its core function is to utilize the cathodic protection of the zinc layer to effectively prevent corrosion of the steel substrate, thus significantly extending its service life.
What types of galvanized steel sheets are there? Galvanized steel sheets can be divided into the following categories based on their production and processing methods:
*Hot-dip galvanized steel sheet: This type of steel sheet is made by immersing the steel sheet in a bath containing molten zinc, allowing the zinc to adhere to the surface of the steel sheet. The steel is immersed in molten zinc at 450℃, resulting in a coating of 50–120 µm, with the strongest adhesion and outdoor corrosion resistance for 20–30 years.
Alloy galvanized steel sheet: Alloy galvanized steel sheet is also manufactured using the hot-dip method. However, this method requires immediate heating to approximately 500℃ after removal from the bath to form an alloy film of zinc and iron. Alloy galvanized steel sheet has excellent adhesion and weldability.
Electro-galvanized steel sheet: This type of galvanized steel sheet, prepared using electroplating, has good processing performance. However, the zinc coating is thinner and its corrosion resistance is not as good as hot-dip galvanized steel. Electro-galvanized steel has a thin coating (5-25μm), a bright appearance, and precise dimensions, making it suitable for precision parts.
Continuously galvanized steel sheet: The steel sheet is continuously immersed in a molten zinc bath for galvanizing. Due to its uniform coating and high production efficiency, this galvanizing method is often used in the manufacture of automotive parts and household appliances. The steel strip passes through a 460℃ zinc bath at high speed, resulting in a coating of 7–30 µm with a bright surface, which is then used for color-coated substrates.
What materials can be used as the substrate for galvanized steel sheets?
The substrate for galvanized sheets is primarily made of metallic materials, the most common being low-carbon steel.
Low-carbon steel: As one of the main materials for galvanized sheet substrates, low-carbon steel’s ductility and strength meet the high-temperature and chemical reaction requirements of the galvanizing process. Furthermore, low-carbon steel has good weldability, facilitating further processing and joining after galvanizing.
Stainless steel: Although less common, stainless steel galvanized sheet substrates possess extremely high corrosion resistance and durability, maintaining stable performance over long periods under harsh environmental conditions. This makes stainless steel galvanized sheets widely applicable in marine engineering, chemical industries, and other fields.
Cold-rolled steel: This substrate is often used in applications requiring a smooth surface, making it ideal for electro-galvanized sheets.
The following are commonly used grades of galvanized steel sheets.
| Brand | Standards system | stamping grade | Correspondence |
| DX51D+Z | European Standard EN 10346 | General grade | ≈ SGCC ≈ DC51D+Z |
| DX52D+Z | European Standard | stamping grade | ≈ SGCD1 ≈ DC52D+Z |
| DX53D+Z | European Standard | Deep-drawing | ≈ SGCD2 ≈ DC53D+Z |
| SGCC | Japanese Standard JIS G 3302 | General grade | ≈ DX51D+Z |
| DC51D+Z | National Standard GB/T 2518 | General grade | ≈ DX51D+Z |
Zinc coating grade comparison table for galvanized steel sheets
| Zinc coating grade | Zinc coating grade | Single-sided zinc layer thickness (approx.) | Corrosion resistance rating | Typical applications |
| Z60 | 60 g/m² | ≈4.2μm | Indoor / Light Protection | Home appliance internal components and indoor equipment |
| Z80 | 80 g/m² | ≈5.6μm | Indoor general | Electrical cabinets, appliance casings |
| Z100 | 100 g/m² | ≈7.0μm | Indoor / Light Outdoor | Home appliance panels, light building |
| Z120 | 120 g/m² | ≈8.4μm | General outdoor | Construction site hoardings, billboards |
| Z180 | 180 g/m² | ≈12.6μm | Outdoor Standard | Building color steel plate substrate |
| Z275 | 275 g/m² | ≈19.3μm | Highly corrosive environments | Coastal buildings and chemical plants |
Galvanized steel sheet is an indispensable component across various industries, boasting superior durability and corrosion resistance. Jindalai Steel Group Co., Ltd., as a trusted manufacturer, offers a range of galvanized steel sheets to meet diverse needs. By understanding the functions of different types of galvanized steel sheets, substrates, grades, and zinc coatings, businesses can make informed decisions, thereby improving project efficiency and lifespan. Whether in construction, automotive, or manufacturing, galvanized steel sheet remains the preferred choice for quality and performance.
Post time: Jun-17-2026
