Factory-direct steel gratings & stair treads, shipped worldwide
HDG Grating
HDG Grating: every batch ships with traceable mill test certificates.
Itemized quote within 24 hours · Free drawing review included
Hot-dip galvanized after fabrication
2–3 day cycle at our certified partner, inside the production window
Certified & tested
MTC EN 10204 Type 3.1, coating sampled to ASTM A123 / ISO 1461
Samples in 5–7 days
Production in 15–25 working days, galvanizing included
FOB Tianjin
Shipped worldwide, EXW / CIF negotiable
Material comparison
Steel Grating Material Comparison
Material is the first filter in a grating spec. Pick the environment first, then the corrosion demand, then the cost level — this table compresses that decision into three steps, with the hot-dip galvanized row highlighted as this page's material.
| Material | Corrosion protection | Typical environments | Relative cost level | Documents & checks |
|---|---|---|---|---|
| Hot-Dip Galvanized Q235B | Zinc metallurgically bonded to the steel; shields cut edges and scratches | Outdoor, municipal, wet industrial sites | Moderate | MTC per heat + coating sampling to ASTM A123 / ISO 1461 |
| Black carbon steel (Q235B) | None as-supplied — needs coating on site or mill oil for transit | Indoor floors, or fabricator-finished work | Lowest | MTC per heat |
| SS304 stainless | Alloyed chromium oxide film through the full section | Food plant, chemical washdown, clean interiors | Higher | MTC per heat, grade traceable |
| SS316 stainless | Adds molybdenum for chloride-rich exposure | Marine, coastal, saline mist | Highest | MTC per heat, grade traceable |
Not sure which material fits your site? Send your drawings — we'll spec it inside the 24-hour quote.
The process, not just the finish
What Hot-Dip Galvanizing Actually Is
Most grating buyers write "HDG" on a purchase order without ever seeing what happens inside the kettle. Here is the process your HDG steel grating goes through after fabrication — and why the result is not a coating in the paint sense at all.
A finished panel is lowered into a bath of molten zinc. The heat triggers a reaction between iron and zinc, and a stack of zinc–iron alloy layers grows outward from the steel itself, capped by a free-zinc surface. At the interface the coating and the steel are continuous — a metallurgical bond, not an adhesive one — so it cannot peel or flake the way paint film can.
Why cut edges stay protected
Grating panels are cut and banded to size, so fresh steel is always exposed somewhere — saw cuts, banding welds, drilled fixing holes. A barrier-only coating would fail there first. Zinc works two ways: it seals the surface, and wherever bare steel shows, the surrounding zinc corrodes preferentially and shields the exposed edge electrochemically. That is why HDG grating tolerates site handling and cut-to-size work far better than painted equivalents.
The 2–3 day cycle, inside your production window
After fabrication and first-article inspection, panels travel to our long-term certified galvanizing partner near the mill. Degreasing, pickling, fluxing, immersion, quenching and coating checks run 2–3 days — and that cycle is already counted inside the 15–25 working-day production window you are quoted, not added afterwards. Coating thickness is sampled to ASTM A123 / ISO 1461 before release, the fourth stage of our five-stage QC.
Need the finish-and-designation overview instead of the process story? See Hot-Dip Galvanized Grating — this page stays on how the coating itself works.
Why specify HDG
Why Buyers Specify HDG Steel Grating
Rust-resistant by chemistry, not by paint
The zinc is bonded into the steel at the layer level and keeps protecting cut edges — a corrosion-resistant finish for rain, road salt and washdown humidity, batch tested before release.
Made to spec — any size, grade options
Panels are cut and banded to your drawings before they enter the zinc bath, so every edge is coated. Q235B is the standard base; grade options are quoted to order. Small MOQ welcome.
Factory-direct, no middlemen, mill certs
You buy from the mill, not a trading desk — and every batch of HDG steel grating is traceable to its heat through mill test certificates, ready to preview before you commit.
Applications
Where HDG Grating Earns Its Zinc
HDG steel grating is the default wherever weather, splash and salt meet steel flooring — the wet sites where an uncoated panel would show rust streaks within one season.
Municipal trench & drain covers
Rain, de-icing salt and street washdown — the classic duty for galvanized Q235B. See trench drain covers.
Outdoor walkways & platforms
Open mesh sheds water and ice; the zinc keeps the frame sound year after year. See walkway grating.
Exterior stairs & fire escapes
Galvanized treads with serrated or plain surfaces, banded edges coated after fabrication.
Wet & washdown sites
Perimeter drainage, pump zones and humid plant floors where standing moisture rules out bare steel.
Specifications
HDG Grating Specifications
| Parameter | Range |
|---|---|
| Bearing bar | 20×3 mm to 100×8 mm, plain or serrated |
| Bar spacing | 30 / 40 / 60 mm centers |
| Panel width × length | Up to 1.25 m × 6 m |
| Base material | Q235B carbon steel · SS304 / SS316 on request |
| Surface | Hot-dip galvanized after fabrication (ASTM A123 / ISO 1461) |
| Stock designation | 19W4 and custom equivalents |
| Processes | Welded or press-locked |
Mill Test Certificates (EN 10204 Type 3.1)
We ship mill test certificates (EN 10204 Type 3.1) with every shipment, so the Q235B chemistry behind your HDG grating is traceable to its heat — verified at goods-in, the first of our five QC stages. What travels with the panels:
- Mill test certificate to EN 10204 Type 3.1, per heat
- Coating thickness sampling to ASTM A123 / ISO 1461, per galvanized batch
- Factory inspection report with every shipment
- Declaration of Conformity prepared per order destination
Certifications & documents → · Coating standards explained →
Standards & compliance
Produced to Recognized Standards — Documents on Request
ASTM A123 / ISO 1461 HDG
The governing hot-dip galvanizing standards — coating thickness is sampled on every galvanized batch before panels are released.
ANSI / NAAMM MBG 531
Welded HDG panels produced to MBG 531 reference practice, with weld inspection on our five-stage QC plan.
CE & SGS tested
Certified & tested, reports on request — we show documents you can verify, not a certificate wall.
Custom made
Custom HDG Panels, Cut and Banded to Your Drawings
Send your drawing
Panel sizes, load specs, quantities — or just photos and a sketch. Drawing review is free.
Quote within 24 hours
Itemized, FOB Tianjin as standard — EXW or CIF on request. Small trial orders welcome, material certs ready to preview.
Samples in 5–7 days, production in 15–25
Working days after drawing confirmation — the 2–3 day galvanizing cycle included. Installation drawings and fixing layout ship with the order.
Factory-direct quote
Get a Factory Quote
Send your HDG grating specs for a factory quote — material certs ready to preview before you commit. Itemized reply within 24 hours, free drawing review included.
- Five-stage QC, from MTC verification at goods-in to post-galvanizing coating checks
- DoC, MTC EN 10204 3.1 and inspection report with every order
- Factory audits welcome — see the lines and the galvanizing route before you commit
Prefer to talk? WhatsApp us or sales@dtsteelladder.com
Request your quote
Five fields — we do the rest.
FAQ
Frequently Asked Questions
What certificates come with an HDG grating order?
You receive mill test certificates (EN 10204 Type 3.1) with every shipment, covering the Q235B heat chemistry, plus a factory inspection report. The galvanized coating itself is sampled to ASTM A123 / ISO 1461 before release.
Does galvanizing delay my production schedule?
No — panels spend 2–3 days at our certified galvanizing partner near the mill, and that cycle is already counted inside the 15–25 working-day production window quoted after drawing confirmation. Samples ship in 5–7 working days.
HDG or stainless steel — which should I choose?
Hot-dip galvanized Q235B is the default for outdoor, municipal and wet-site grating. SS304 or SS316 earns its premium in food, chemical and marine chloride exposure, while black steel suits indoor or coat-on-site work. Tell us the environment and we will recommend honestly.
Related pages
Related Material Grating Pages
Hot-Dip Galvanized Grating
The finish and designations overview — coating standards and thickness sampling.
View page →Grating HDG
The same HDG process applied across the full grating catalog.
View page →Galv Grating
The galvanized line overview — HDG as the default weather protection.
View page →Grating Galvanized Steel
Q235B core plus zinc finish — material framing and batch coating checks.
View page →Galvanized Steel Grating Panels
Panel formats in galvanized steel, from trench covers to platforms.
View page →Black Grating
Uncoated mill finish — when you coat on site or specify HDG later.
View page →