Overview

Composite compound steel grating combines a steel load‑bearing framework with a polymer‑filled surface layer to deliver high strength, corrosion resistance, and slip‑resistant traction. The product is fabricated in a single facility that controls raw material selection, forming, and finishing, which reduces variability and lead time compared with multi‑sourced assemblies.

Material Composition and Structure

The bearing bars are typically hot‑rolled carbon steel grades such as Q235 or S355, selected for yield strength ranging from 235 MPa to 355 MPa. The cross rods are made from the same steel grade to ensure uniform mechanical properties. A polymer compound, often a polyurethane‑based filler, is applied over the steel matrix and cured to form a continuous wear surface.

Typical surface thickness ranges from 2 mm to 4 mm, providing abrasion resistance while maintaining overall grating weight below 30 kg/m² for standard 30 mm bar spacing. The polymer layer adds a coefficient of friction of approximately 0.6 – 0.8 under dry conditions, meeting common slip‑resistance criteria.

Manufacturing Process

Steel coils are slit to the required bar width, then punched or slotted to create the open area pattern. The bars are resistance‑welded at each intersection to form a rigid grid. After welding, the grating undergoes shot blasting to remove scale and improve adhesion.

The polymer compound is mixed, degassed, and applied via a curtain‑coating or extrusion method, ensuring uniform coverage. Curing occurs in a controlled‑temperature oven at 150 °C – 180 °C for 10 – 15 minutes, after which the product is cooled, inspected, and cut to length.

Technical Specifications

Property	Typical Value	Unit
Bar thickness	3 – 5	mm
Bar spacing (center‑to‑center)	30 – 40	mm
Open area ratio	70 % – 80 %	–
Surface polymer thickness	2 – 4	mm
Yield strength of steel	235 – 355	MPa
Weight per square meter	20 – 30	kg/m²
Coefficient of friction (dry)	0.6 – 0.8	–

Load‑Bearing Performance

Deflection under uniform load follows the formula δ = (5 w L⁴)/(384 E I) for simply supported bars, where w is load per unit length, L is span, E is modulus of elasticity (~200 GPa for steel), and I is the second moment of area of the bar section. For a 30 mm × 3 mm bar spanning 600 mm, a 5 kN/m² load produces a deflection of approximately 2 mm, well within typical service limits of L/200.

Impact resistance is enhanced by the polymer layer, which absorbs kinetic energy and reduces stress concentration at the weld points. Drop‑test data indicate that a 5 kg mass dropped from 1 meter causes no permanent deformation in standard configurations.

Applications

Industrial walkways and platforms where chemical spills or oily substances are present, because the polymer surface resists permeation and facilitates cleaning.
Drainage covers in food‑processing facilities, where the open area allows liquid passage while the slip‑resistant top reduces fall hazards.
Trench grates in petrochemical plants, where corrosion‑resistant steel grades combined with a protective coating extend service life in saline environments.
Stair treads in power generation sites, where high load capacity and fire‑retardant polymer additives meet safety regulations.

Quality Control and Testing

Each batch undergoes visual inspection for weld continuity, surface uniformity, and dimensional accuracy. Laser scanning verifies bar spacing and open area ratio within ±2 % tolerance.

Mechanical tests include tensile strength on extracted bar samples, bend tests to assess ductility, and hardness measurements on the polymer layer (Shore A 80 ± 5). Corrosion resistance is evaluated via salt‑spray exposure (ASTM B117) for 500 hours, with acceptable rust rating ≤ 1 % of surface area.

Final product is marked with a batch code that links to raw material certificates and test reports, enabling traceability for audit purposes.

Customization Options

Bar thickness: 2 mm – 8 mm
Spacing: 20 mm – 50 mm (center‑to‑center)
Steel grade: Q235, Q345, S355, or stainless‑steel alternatives
Polymer type: polyurethane, epoxy‑modified acrylic, or UV‑stabilized variants
Surface pattern: plain, serrated, or diamond‑groove for enhanced slip resistance
Edge treatment: flat, rounded, or with integrated lifting lugs

Packaging and Logistics

Grating sections are stacked on pallets with protective corner guards and wrapped in stretch film to prevent shifting during transit. For overseas shipments, the pallets are placed in fumigated wooden crates that meet ISPM 15 standards.

Standard load capacity per pallet is 1 tonne, allowing efficient container utilization. Custom packing arrangements, such as vertical stacking or crate‑free bundles, are available upon request to suit specific handling equipment.

Frequently Asked Questions

Can dimensions be customized? Yes, bar thickness, spacing, and overall panel size can be adjusted to match project drawings; provide span, load, and clearance requirements for a quotation.

What information is required before quotation? Supply the intended application, load conditions, environmental exposure (e.g., chemical, salinity), and any required certifications (e.g., ISO 9001, CE).

What materials are available? Carbon steel grades Q235/Q345, structural steel S355, and optional stainless steel (304/316L); polymer options include polyurethane, epoxy‑acrylic, and UV‑stable blends.

How is quality inspected? Each lot undergoes dimensional checks, weld inspection, mechanical testing on samples, and corrosion‑resistance testing per ASTM standards; test reports are shipped with the order.

What packaging methods are available? Standard palletized stretch‑film wrapping, wooden crate packaging for export, and custom bundles or vertical stacks as needed.

How are export shipments protected? Pallets are secured with strapping, corner protectors, and heat‑treated wooden crates compliant with ISPM 15 to prevent pest infestation.

What is the typical production lead time? Lead time ranges from 2 to 4 weeks depending on order complexity and current plant capacity; expedited schedules are possible for stocked profiles.

How are samples arranged? Sample panels (up to 500 mm × 500 mm) can be sent via express courier; request samples with the intended specification to evaluate fit and finish.

Contact for Technical Inquiry

For detailed load calculations, material selection guidance, or to request a formal quotation, reach out to the engineering team using the contact form linked below.

Request Quotation