Hot-Dip Galvanized Stair Tread – Safe Anti‑Slip Steps for Industrial Ladders & Maintenance Platforms

Hot-dip galvanized stair treads are step products made from steel grating panels that have been hot-dip galvanized. They are widely used for industrial plant steel ladders, equipment maintenance platform stairs, offshore platform stairways, and wastewater treatment plant stairs. Compared to conventional checkered plate treads, hot-dip galvanized steel grating treads offer high load capacity, serrated anti‑slip surface (friction coefficient ≥0.6), open design (no water pooling), light weight, easy installation, and long service life (20–30 years).

Hot-dip galvanized stair treads are typically made of serrated models such as G255/30/100F and G325/30/100F, with bar heights of 25–32mm and bar pitch of 30mm. A slip‑resistant nosing (checkered plate or flat bar) is welded to the front edge. Side plates can be added for bolted connections. Each tread is hot-dip galvanized with a coating thickness ≥65μm, ensuring long‑term corrosion protection in outdoor and humid environments.

As a professional manufacturer of hot-dip galvanized stair treads, we provide one‑stop service from load calculation, specification selection, welding forming, hot-dip galvanizing to on‑site installation guidance. Below is a complete technical introduction.

1. Load Classes & Selection Principles for Hot-Dip Galvanized Stair Treads

The load capacity of a stair tread depends on bar height, bar pitch, tread width, and support method. The table below lists common load classes and recommended models:

Selection Principles:

1. Bar height 25mm for light pedestrian ladders; 32mm for most industrial stairs; 40mm+ for heavy duty.

2. Serrated bars (suffix F) are standard – significantly better slip resistance than plain bars.

3. Tread width typically 200–300mm; length custom based on stair width (commonly 600–1200mm).

4. A slip‑resistant nosing (4–6mm checkered plate) is a standard safety feature.

5. Each tread must be securely welded or bolted to stair stringers; support span must not exceed design value.

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2. Specification & Load Table for Hot-Dip Galvanized Stair Treads

The table below lists the most common specifications for hot-dip galvanized stair treads. All models can be custom-sized.

Specification Notes:

• Bar material: Q235B / ASTM A36 / S235JR

• Serrated bars: Periodic serrations rolled on surface, friction coefficient ≥0.6

• Front nosing: Checkered plate or serrated flat bar, welded securely

• Side plates: Optional 6mm flat bar with bolt holes for bolted connection

• Surface treatment: Hot-dip galvanized, coating thickness ≥65μm (ASTM A123 / GB/T 13912)

• Applicable standards: GB/T 17888.3-2008, ISO 14122-3, OSHA 1910.24

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H2: 3. Full Product Line of Hot-Dip Galvanized Stair Treads

H3: 3.1 Standard HDG Stair Tread (with Front Nosing)

The most common type – serrated bar grating with a 4–6mm checkered plate nosing welded to the front edge. Suitable for most industrial steel ladders and maintenance platform stairs.

Common models: G255/30/100F, G325/30/100F

Features: Excellent slip resistance, durable nosing, fully hot-dip galvanized.

3.2 HDG Stair Tread with Side Plates (Bolted Type)

Flat bar side plates are welded to both ends of the tread, with pre‑drilled bolt holes for bolted connection to stair stringers. Ideal for stairs requiring disassembly or where field welding is not allowed.

Common models: G325/30/100F with side plates, G405/30/100F with side plates

Features: Easy installation and removal, no field welding, side plates add rigidity.

3.3 Fully Serrated HDG Stair Tread (without Nosing)

The tread is made entirely of serrated bearing bars – no additional checkered plate nosing. Suitable for stairs where maximum drainage and ventilation are needed, and a sealed edge is not required.

Common models: G325/30/100F (no nosing)

Features: Fully serrated, consistent slip resistance, open design, lighter weight.

3.4 Closed (Composite) HDG Stair Tread

A checkered plate or flat plate is laid on the grating surface, forming a solid tread. Suitable for preventing small tools from falling through or where a solid surface is required.

Common models: HF-G325/30/100F composite tread

Features: Non‑perforated surface, drip‑proof, easy to clean, fully hot-dip galvanized.

3.5 Custom‑Shape HDG Stair Tread

Sector, trapezoidal, or curved treads for special stair designs (e.g., spiral stairs, corner landings). CNC cut, bent, and welded from CAD drawings.

Applications: Sector stair landings, curved steel ladders, corner access stairs

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4. Key Design Elements for Hot-Dip Galvanized Stair Treads

4.1 Anti‑Slip Design (Safety First)

Standard configuration: Serrated bars + checkered plate nosing – meets safety requirements for most industrial stairs.

4.2 Stair Tread Dimensions

4.3 Installation Methods

Welding requirement: Grind welds and touch up with zinc‑rich primer (≥70% zinc).

4.4 Load & Deflection Control

• Design live load for stair treads: industrial ≥4 kN/m², general access ≥3 kN/m²

• Maximum allowable deflection: span / 200

• Recommended support span (stringer spacing) ≤1200mm

4.5 Front Nosing Details

• Material: Checkered plate (Q235B, diamond or teardrop pattern)

• Thickness: Light duty 4mm, medium 5mm, heavy 6mm

• Welding: Full or intermittent (e.g., 50mm weld every 200mm), weld leg ≥4mm

• Surface treatment: Hot-dip galvanized together with tread body

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5. Production Process of Hot-Dip Galvanized Stair Treads

Our plant strictly follows the process below to ensure every product meets export standards:

1. Raw material inspection – MTC for bars and cross bars (Q235B/A36)

2. Grating welding – Fully automatic resistance welding line, strong welds, flat surface

3. Cutting & hole punching – Plasma/laser cutting to required dimensions

4. Serrating – Roll serrations on bar surface (for serrated models)

5. Nosing welding – Weld checkered plate nosing to front edge; grind smooth

6. Side plate welding (if required) – Weld flat bar side plates; drill bolt holes

7. Hot-dip galvanizing:

• Pretreatment: Degreasing → Pickling → Fluxing

• Galvanizing: Zinc bath 445–465°C, immersion 2–4 minutes

• Post-treatment: Centrifuging/air knife → Passivation & cooling

• Coating thickness: ≥65μm (typical 65–85μm, custom thickening available)

8. Final inspection – Coating thickness test, weld inspection, dimensional check, anti‑slip verification

Quality commitment: Each batch includes material test certificate and coating thickness test report.

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6. Installation & Fixing of Hot-Dip Galvanized Stair Treads

6.1 Welded Installation (Permanent)

• Weld tread ends securely to stair stringers (channel or angle steel)

• Weld length ≥50mm per end, weld leg ≥5mm

• Grind and touch up with zinc‑rich primer

6.2 Bolted Installation (Removable)

• Use M10–M16 hot-dip galvanized or stainless steel bolts

• Bolt torque: 20–30 N·m

• Use spring washers to prevent loosening

6.3 Installation Notes

• Bearing bar direction must be perpendicular to walking direction

• Stringer spacing must not exceed design span

• Levelness deviation per tread ≤3mm

• Height difference between adjacent treads ≤5mm

• Ensure the nosing faces upward after installation

• Tighten all fasteners

6.4 Acceptance Criteria

• No warping or deformation

• Full penetration welds, no cracks

• Uniform galvanized coating, no missed areas

• Serrations clearly visible

• No abnormal noise or wobbling during walk test

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7. Typical Application Industries for Hot-Dip Galvanized Stair Treads

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8. Customization & Procurement Guide

As a direct manufacturer of hot-dip galvanized stair treads, we offer comprehensive custom services:

• ✅ Material: Q235B, ASTM A36, S235JR, S355JR

• ✅ Bar sizes: Height 25–50mm, thickness 5–6mm

• ✅ Grid spacing: Bar pitch 30/40mm, cross bar pitch 50/100mm

• ✅ Serrated: Standard (F model), plain optional

• ✅ Tread dimensions: Width 200–350mm, length 600–1500mm (from CAD drawings)

• ✅ Nosing: Checkered plate 4/5/6mm thick, or serrated bar nosing

• ✅ Side plates: Optional 6mm flat bar with bolt holes

• ✅ Surface treatment: Standard HDG (65–85μm), thick HDG (85–120μm)

• ✅ Custom shapes: Sector, trapezoidal, curved treads

Packaging: Steel banding + wooden pallet, with spacers between treads to prevent scratching

Lead time: ≤500 pieces → 7–10 days; >1000 pieces → 15–20 days

Incoterms: FOB Tianjin/Shanghai/Ningbo, CIF major ports, or EXW factory