GI sheet, short for galvanized steel sheet, is the most economical and widely used anti-corrosion metal material. With the dual advantages of a pure zinc coating and substrate strength, it has become a primary anti-corrosion material in the construction, home appliance, and industrial sectors.
GI Sheet Process
The processing technology of GI sheet determines its cost, surface finish, corrosion resistance lifespan, and application environment. Wanzhi Group’s galvanized steel is mainly divided into two types: hot-dip galvanizing (HDG) and electro-galvanizing (EG).
- Hot-dip galvanized sheet: The substrate is immersed in molten pure zinc and heated at high temperature to complete the metallurgical reaction, forming a thick zinc layer. Upon cooling, irregular spangles of varying shapes and sizes are formed on the surface, making it suitable for harsh environments with high corrosion resistance requirements, such as outdoor and industrial applications.
- Electro-galvanized sheet: The substrate is immersed in an electrolyte containing zinc ions, and a uniform zinc layer is physically deposited on the surface through an electrochemical reaction. The surface is smooth without obvious zinc crystal patterns. Its corrosion resistance is weaker than hot-dip galvanized sheet, making it suitable for precision machining and decorative applications.
GI Sheet Substrate
The substrate is a crucial component of the GI sheet, determining its mechanical properties and processing adaptability. Applications range from common scenarios such as building envelopes, general hardware, and ventilation ducts; to load-bearing scenarios such as load-bearing structures, purlins, shelves, and building frames; to functional scenarios such as electrical enclosures, chassis and cabinets, and automotive interior components; and to precision and high-end scenarios such as complex stamped parts, precision components, and high-end home appliances.
- Commercial grade (e.g., DX51D+Z, DC51D+Z (EN 10346)): General forming performance, good flatness, moderate ductility (elongation ≥18%), suitable for applications requiring simple bending and cutting.
- Structural steel (e.g., S350GD, Q235B+Z (GB/T 3274)) has high strength, with a yield strength ≥350MPa and tensile strength ≥375MPa. It is primarily used as a raw material for load-bearing components and can be welded.
- Stamping grade steel (e.g., DX53D, DC53D+Z (EN 10346)) has relatively high elongation, ≥24%, and can be processed by shallow stamping and roll forming. It is suitable as a raw material for medium-formability metal materials.
- Deep drawing grade steel (e.g., DX56D, DC56D+Z (EN 10346)) has excellent ductility (elongation ≥30%), meeting the requirements of deep drawing and preventing cracking during complex shaping.
GI Sheet Chemical Composition
The chemical composition of GI galvanized steel sheet comprises two parts: the substrate and the plating, which are key factors affecting performance stability.
Substrate
| Element | Content range |
| C | ≤0.12% |
| Si | ≤0.05% |
| Mn | ≤0.50% |
| P | ≤0.035% |
| S | ≤0.035% |
Coating
Pure zinc (Zn≥99.95%).
| Coating designation | Total weight on both sides (g/m²) | Average thickness per side (μm) |
| Z30 | 30 | 4.2 |
| Z60 | 60 | 8.4 |
| Z90 | 90 | 12.6 |
| Z120 | 120 | 16.8 |
| Z180 | 180 | 25.2 |
| Z275 | 275 | 38.5 |
GI Sheet Mechanical Properties
| Base Sheet Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation (% , L0=80mm) | Bending Performance (180°) |
| Commercial Grade | ≥190 | 270-410 | ≥18 | No cracks (bending radius = 2t) |
| Structural Steel | ≥235 | 375-500 | ≥22 | No cracks (bending radius = 3t) |
| Stamping Grade | ≥180 | 260-380 | ≥24 | No cracks (bending radius = 1t) |
| Deep Drawing Grade | ≥170 | 250-360 | ≥30 | No cracks (bending radius = 0.5t) |
GI Sheet Sizes
Wanzhi Group manufactures and sells GI sheets in the following sizes: thickness: 0.12mm – 6.0mm, width: 600mm – 1250mm (slitting available), length: 1000mm – 6000mm (customizable). If you cannot find the right galvanized sheet for your project, please leave a message telling us the size you need, and we will provide customization services.
Gauge to mm Conversion
| Gauge | inch | mm |
| 30 | 0.0120 | 0.30 |
| 28 | 0.0149 | 0.38 |
| 26 | 0.0179 | 0.45 |
| 24 | 0.0239 | 0.61 |
| 22 | 0.0299 | 0.76 |
| 20 | 0.0359 | 0.91 |
| 18 | 0.0478 | 1.21 |
| 16 | 0.0598 | 1.52 |
| 14 | 0.0747 | 1.90 |
Sheet Weight Calculation
Steel sheet weight (kg) = Thickness (mm) × Width (m) × Length (m) × 7.85
Dimensional Tolerances
Thickness tolerance ±0.05mm, Width tolerance ±2mm, Length tolerance ±3mm
GI Sheet Raw Material (GI coil)
GI sheet is made from GI coil (galvanized steel coil) through a leveling process. Our factory has two GI coil production lines, supporting customized GI steel services for various specifications.
| Specification | Details |
| Thickness | 0.15-6.0mm |
| Width | 600-1250mm |
| Inner Diameter | 508mm/610mm (compatible with flattening machines) |
| Outer Diameter | 1200-2000mm |
| Quality Standards | Compliant with ISO 1461 (hot-dip galvanizing), ISO 898-1 (electro-galvanizing) |
| Coil Weight | 8-10 tons, customizable |
| Storage Requirements | Must be stored in a moisture-proof and light-proof environment |
GI Sheet Finished Products
GI coils are processed into corrugated, trapezoidal, and curved sections using a roll forming machine. They are used in the construction industry as roof panels (angle seam, standing seam), wall panels, and floor decking. Waveform, wave height, and length can all be adjusted according to actual application requirements.
- Advantages: High strength, quick installation, economical and practical.
A composite metal material composed of GI sheet + insulation core material + GI sheet. The insulation core material can be polystyrene (EPS), rock wool, polyurethane (PU), glass wool, etc., used as walls and roofs in clean rooms, cold storage, industrial buildings, and commercial spaces.
- Advantages: Corrosion resistance, thermal insulation, sound insulation.
GI coils are coated with organic coatings (PE, SMP, HDP, PVDF, PU, etc.) by roller coating, cured at high temperature to form a colored coating, and then cut and shaped according to application requirements. Commonly used as building decoration, appliance casings, and infrastructure construction materials.
Advantages: Highly decorative, corrosion-resistant, rich in colors, and highly weather-resistant.
GI Sheet Factory
Wanzhi Group‘s GI sheet factory is located in Xingfu Town, Boxing County, Binzhou City, Shandong Province, China. It possesses full-chain capabilities from raw material production to processing and quality inspection. The factory is certified to ISO9001 and ISO14001D, and its products comply with international standards such as GB, ASTM, JIS, and EN.
- Core Equipment: 2 hot-dip galvanizing production lines (20,000 tons per month), multiple leveling machines (capable of processing up to 1250mm wide), and multiple profiled sheet production lines (capable of producing corrugated, trapezoidal, and other cross-section sheets).
- Quality Control: Equipped with magnetic thickness gauges (for coating thickness detection), tensile testing machines (for mechanical property testing), and salt spray testing machines (for corrosion resistance testing). Quality inspection reports are provided, and third-party quality inspections by SGS and BV are supported.
- Delivery Capability: Standard specifications can be delivered within 5 days, and customized specifications within 45 days.
GI Sheet Price
GI steel sheets are priced in various ways, including per square meter, per ton, and per sheet. Prices are affected by factors such as specifications, coating, quantity, processing method, special requirements (e.g., ultra-flat surface, special zinc spangle), customized specifications, packaging, and shipping. Currently, our galvanized steel price is 600-800 USD/ton. Leave a message telling us your needs or application scenario to get a free quote!
GI Sheet Applications
Galvanized steel is one of the most cost-effective corrosion-resistant coated steel materials, playing a vital role in construction, home appliances, agriculture, transportation, and energy sectors.
Construction Sector
- Roofs/Walls: Hot-dip galvanized profiled sheet/PPGI/PPGL sheet.
- Steel Structure Purlins: Hot-dip galvanized structural steel grade GI Sheet/GI Coil, processed into C-shaped/Z-shaped steel, etc.
- Fences/Guardrails: Hot-dip galvanized commercial grade GI Sheet, GI strips.
- Doors: Galvanized profiled sheet, color-coated profiled sheet.
Home Appliance Sector
- Refrigerator/Washing Machine Back Panels: Electro-galvanized stamping grade GI Sheet.
- Air Conditioner Outdoor Unit Housing: Hot-dip galvanized commercial grade GI Sheet/PPGI sheet.
- Oven Liners: Electro-galvanized deep-drawing grade GI Sheet/GL sheet.
Industrial Sector
- Equipment Housings: Hot-dip galvanized structural steel grade.
- Pipeline Corrosion Protection: Hot-dip galvanized sheet.
- Shelving/Pallets: Hot-dip galvanized commercial-grade steel sheet.
- Agricultural Sector: Greenhouse Frames: Hot-dip galvanized round/square tubes, etc.
- Grain Silo Enclosures: Hot-dip galvanized profiled sheet.
Other Sectors
- Automotive Industry: Structural components, interior components (high-strength substrate + thick coating)
- Transportation Facilities: Highway guardrails, sound barriers (high weather resistance requirements)
If you have your own solutions and are looking for a professional GI Sheet or other metal processing plant, please contact us. Wanzhi Group is happy to provide you with one-stop service!