Hot-Dip Galvanized Steel Grating: Applications, Specifications, And Installation Guide

Hot-dip galvanized steel grating is widely used in various fields due to its high strength, corrosion resistance, and ease of maintenance. The main application scenarios include:

Municipal engineering: Used for road rainwater well covers, drainage ditch covers, bridge sidewalk boards, railings, as well as equipment platforms, inspection walkways, and sewage ditch covers in sewage treatment plants.

Industrial fields: Commonly used in petrochemical, power energy, paper printing, and other industries for operation platforms, equipment platforms, and heavy logistics channels.

Construction engineering: Suitable for basement drainage ditch covers, construction platforms, steel structure accessories, and exterior wall ventilation openings in residential buildings and commercial complexes.

Other scenarios: Also used for landscape gratings in park squares, vent covers, and platforms and walkways at port terminals.

The dimensions of galvanized steel grating are designed in accordance with the national standard GB/T4001.1-2019, including core structural parameters and external dimensions, as shown below:

Application Scenarios

Bearing flat steel: Series 1 (30mm pitch, high load-bearing, for platforms/walkways), Series 2 (40mm, general purpose), Series 3 (60mm, light load/ventilation); thickness 2-5mm, height 20-100mm (e.g., 25×3, 30×5, 50×5mm), serrated anti-slip type, and Type I is more material-efficient.

Cross bar: Mainly twisted square steel (5×5/6×6/8×8mm), with Series 1 matched with 100mm pitch, Series 2 matched with 50mm pitch (anti-fall).

Mesh size: Common sizes include 30×100, 40×50, 50×100mm (large holes for drainage, small holes for anti-fall).

Length: 1-6m (standard 2/3m; reinforcing ribs are required for overlength >6m)

Width: 300-1000mm (commonly 500/600/800mm)

Thickness = height of flat steel + diameter of cross bar (e.g., 30mm flat steel + 6mm cross bar ≈ 36mm)

G303/30/100 (30mm high × 3mm thick flat steel, 30mm flat steel pitch, 100mm cross bar pitch): 1m×2m/3m general platform

G255/30/50 (25×5mm flat steel, 30×50mm mesh): anti-slip step plate

G403/40/100 (40×3mm flat steel, 40×100mm mesh): drainage ditch cover

Selection Guide: Use Series 1 + 100mm cross bar for industrial platforms, serrated type + 50mm cross bar for stair treads, large holes + thick flat steel for municipal ditch covers. Customization is available for special-shaped/overlength products (note: ≥50mm between cutting edge and welding point to prevent rust).

When selecting the size of galvanized steel grating, the following key factors need to be comprehensively considered:

Load-bearing requirements: Determine the height, thickness of the bearing flat steel, and cross bar pitch based on the maximum static and dynamic loads of the application scenario (such as industrial platforms, stair treads, drainage ditch covers). For example, Series 1 (30mm flat steel pitch) with 100mm cross bar pitch can be selected for industrial platforms requiring high load-bearing capacity; Series 2 (40mm flat steel pitch) with 50mm cross bar pitch can be selected for stair treads requiring anti-fall performance.

Anti-slip and safety: In wet, inclined, or pedestrian-intensive areas (such as stair treads), serrated flat steel is preferred; for scenarios with high anti-fall requirements (such as high-altitude platforms), reduce the mesh size (e.g., 30×50mm).

Installation environment: The installation space size (such as ditch width, platform size) determines the external dimensions; reinforcing ribs are required for overlength (>6m) or special-shaped products; in corrosive environments (such as chemical plants), increase the zinc coating thickness (≥85μm, complying with GB/T 13912-2025) and ensure ≥50mm between the cutting edge and welding point to prevent rust.

Production process: Press-welded type with standard dimensions, suitable for general scenarios; interlocking type can be customized for special-shaped dimensions to meet special installation requirements.

Cost and weight: Under the premise of meeting load-bearing requirements, balance cost and weight by optimizing flat steel specifications (such as Type I flat steel) and mesh size to avoid over-design.

Combine the specific requirements of the application scenario (such as platforms, treads, ditch covers) and the above factors to determine the appropriate size.

The weight of galvanized steel grating needs to comprehensively consider the weight of bearing flat steel, cross bars, and the increase due to the zinc coating. The core formula is:Total weight (kg/m²) = (Weight of bearing flat steel + Weight of cross bars) × Zinc coating weight increase factor

Weight of bearing flat steel

Weight per single flat steel (kg/m) = Width of flat steel (mm) × Thickness of flat steel (mm) × 0.00785 (steel density)

Total weight of flat steel per square meter = Weight per single flat steel × Number of flat steels per square meter (Number = 1000 ÷ Flat steel pitch + 1)

Weight of cross bars

Weight of twisted square steel cross bar (kg/m) = Side length (mm)² × 0.00617 (square steel density)

Total weight of cross bars per square meter = Weight per single cross bar × Number of cross bars per square meter (Number = 1000 ÷ Cross bar pitch)

Zinc coating weight increase factor

×1.12 for flat steel pitch 30mm, ×1.14 for 40mm (refer to GB/T 13912-2025)

Example: G325/30/100 (32mm × 5mm flat steel, 30mm pitch, 100mm cross bar pitch)

Flat steel: 32×5×0.00785 = 1.256kg/m, Number = 1000÷30+1 ≈ 34, Total weight = 1.256×34 = 42.704kg

Cross bar (6mm square steel): 6×6×0.00617 = 0.22212kg/m, Number = 1000÷100 = 10, Total weight = 0.22212×10 = 2.2212kg

Total weight after galvanizing = (42.704 + 2.2212) × 1.12 ≈ 50.3kg/m²

Notes:

In actual production, the width/thickness of flat steel may have deviations (e.g., 32mm flat steel is actually 31mm, 5mm thickness is actually 4.75mm), which shall be based on the measured dimensions.

Special-shaped gratings or gratings with reinforcing ribs need to calculate the weight of special parts separately.

For accurate weight, it is recommended to consult the manufacturer and provide the model (such as G303/30/100) to obtain official data.

The following key matters should be noted when installing galvanized steel grating to ensure safety and stability:

1. Pre-Installation Preparation

Base treatment: Clean the supporting frame, check the strength and levelness, mark the installation line, and place the plates according to the drawing numbers.

Material inspection: Verify the grating specifications (such as G303/30/100) to ensure no rust spots or cracks; stacking height ≤ 1.2 meters.

2. Core Installation Methods

Welding fixation (permanent projects): The bearing flat steel shall have a bearing length ≥25mm at both ends, fillet weld length ≥20mm, height ≤3mm. Clean the weld slag and perform anti-rust treatment after welding.

Clamp fixation (removable scenarios): At least 4 special installation clamps per plate, with anti-loose washers and bolts of diameter ≥8mm.

**Decorative grating: Fixed with nail-free glue + nail gun, or sealed with caulking after snap-in installation.

3. Safety and Load-Bearing Requirements

Load-bearing specifications: Support span 800-1000mm for pedestrian passages, 1000-1200mm for equipment platforms, 1200-1500mm for heavy-duty areas; average load ≤ 2.5kN/m² for industrial platforms.

High-altitude operation: Wear safety belts above 2 meters, set lifelines, stop operations in rain, snow, or windy days, and use anti-drop bags for tools.

Prohibition warning: Square movable grating plates are prohibited (positioning measures are required), gap between plates ≤15mm, and overloading is strictly prohibited.

4. Acceptance and Maintenance

Acceptance inspection: Test flatness and firmness, treat corners with internal and external corner lines and make up welds.

Later maintenance: Regularly check for corrosion and loose bolts, replace damaged parts in a timely manner, and keep drainage unobstructed.

Strictly following the above steps can ensure the safe and durable installation of galvanized steel grating.

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Q: What materials are commonly used for steel grating?

A: Steel grating is typically made of carbon steel (Q235B) with hot-dip galvanized surface treatment for corrosion resistance. Stainless steel (304/316) and aluminum alloy are also available for high-corrosion environments like chemical plants or coastal areas.

Q: What are the main applications of steel grating?

A: It is widely used as walkways, platform floors, stair treads, drainage covers, trench grates, and safety fences in industrial plants, power plants, sewage treatment facilities, ports, and municipal engineering projects.

Q: What are the advantages of hot-dip galvanized steel grating?

A: Hot-dip galvanized steel grating offers excellent corrosion resistance (service life up to 20+ years outdoors), high structural strength, good ventilation and anti-slip properties, and is easy to install and maintain.

Q: How do I choose the right steel grating specifications?

A: You need to consider load-bearing requirements (pedestrian, vehicle, or heavy equipment), span length, anti-slip needs, and environmental conditions (corrosion level, temperature). Common specifications include 30×3mm or 40×3mm bearing bars with pitches of 30/40/60mm.

Q: Can steel grating be customized for special projects?

A: Yes, most manufacturers provide customized services, including special sizes, shapes, load ratings, surface treatments (galvanized, painted, stainless steel), and designs like serrated anti-slip bars or custom cutouts.