Hot-Dip Galvanized H-Beam | HW, HM, HN Series, 30–700 g/m²
Hot-rolled H-beams hot-dip galvanized to EN ISO 1461, ASTM A123 or GB/T 13912 with a zinc coating from 30 to 700 g/m² on all surfaces. Supplied across the HW, HM and HN series from 100×100 to 400×400, cut, drilled and bevelled to your drawing before dipping.
Product Overview
A galvanized H-beam is a hot-rolled wide flange section that has been immersed in molten zinc so that a metallurgically bonded zinc-iron coating forms over the whole profile — flange faces, flange edges, web, cut ends and drilled holes. Galvanizing does not alter the mechanical properties of the steel, so the section that was sized from its bending or buckling capacity is the section that arrives, with strength, stiffness and fatigue performance unchanged.
The parallel flanges are what make galvanizing especially worthwhile on this profile. Structural steel outdoors usually fails first at edges, bolt holes and the inaccessible faces of connections, which is exactly where a paint film is thinnest and hardest to inspect. A zinc coating protects all of those areas sacrificially, so minor handling damage and site drilling do not start a corrosion site.
Stock covers the HW, HM and HN series in base grades Q235B and Q355B, with coating weight nominated against the service environment and quoted as the total on both surfaces. Cutting, drilling and bevelling are completed before dipping so the finished member has coated ends and holes, and a coating mass test report is issued with each lot.
Specifications & Size Range
Galvanized H-beam range with the coating weights normally nominated for each exposure class. Mill lengths are 6 m, 9 m and 12 m; processing to drawing is completed before galvanizing. Sections outside the rolled range can be supplied as a galvanized custom welded H-beam.
| Series | Typical designations (mm) | Depth range (mm) | Coating weight (g/m², both surfaces) | Typical use |
|---|---|---|---|---|
| HW — wide flange | HW100×100, HW150×150, HW200×200 | 100 – 200 | 180 – 275 | Outdoor columns, equipment supports, canopy frames |
| HW — wide flange | HW250×250, HW300×300, HW350×350, HW400×400 | 250 – 400 | 275 – 500 | Coastal plant columns, quay and jetty frames, heavy outdoor structures |
| HM — medium flange | HM200×150, HM250×175, HM300×200, HM350×250, HM400×300 | 200 – 400 | 275 – 400 | Outdoor portal frames, walkway beams, plant structures |
| HN — narrow flange | HN200×100, HN300×150, HN400×200, HN500×200 | 200 – 500 | 275 – 500 | Exposed roof and floor beams, gantry girders, long-span members |
| High-coating | Any series above | as above | 500 – 700 | Marine, chemical and permanently humid service |
Tolerances
Zinc coating to GB/T 13912, EN ISO 1461, ASTM A123 / A153 and JIS H8641, quoted in g/m² total on both surfaces, with a working guide of about 7 µm of coating thickness per 100 g/m². Base section dimensions, straightness and mass follow GB/T 11263. Coating mass is checked on a sample basis per lot and reported with the shipment.
Steel Grades & International Equivalents
All grades below are supplied with a mill test certificate. The right-hand column shows the material type and the Chinese standard the grade is produced to; the middle columns give the nearest recognised equivalent in other national standards. Exact equivalence for a specific project should be confirmed on the enquiry.
| GB (China) | ASTM / AISI (US) | EN (Europe) | JIS (Japan) | DIN (Germany) | Type / Standard |
|---|---|---|---|---|---|
| Q235B + hot-dip galvanized | A123 / A153 (ASTM) | EN ISO 1461 | JIS H8641 | DIN 50976 | Hot-dip galvanized structural steel (GB/T 13912) |
| Q235B | A36 / A283 Gr.C | S235JR (EN 10025-2) | SS400 (JIS G3101) | St37-2 | Carbon structural steel (GB/T 700) |
| Q355B | A572 Gr.50 / A992 | S355JR (EN 10025-2) | SM490 (JIS G3106) | St52-3 | High-strength low-alloy (HSLA) steel (GB/T 1591) |
Grade Notes
- Q235B + hot-dip galvanized — Zinc coating of 30–700 g/m² gives 5–30+ years of atmospheric corrosion protection depending on thickness and environment.
- Q235B — The workhorse structural grade in China. Fully weldable, excellent cost-performance, the closest Chinese equivalent to ASTM A36 / EN S235JR.
- Q355B — High-strength structural steel for heavy structures, bridges and towers. Equivalent to ASTM A572 Gr.50 / EN S355JR.
Chemical Composition (%, ladle analysis)
Typical specification limits. Actual heat values are reported on the mill test certificate supplied with every shipment.
| Grade | C | Si | Mn | P max | S max | Other elements |
|---|---|---|---|---|---|---|
| Q235B | ≤0.20 | ≤0.35 | ≤1.40 | ≤0.045 | ≤0.045 | — |
| Q355B | ≤0.24 | ≤0.55 | ≤1.60 | ≤0.035 | ≤0.035 | Ceq ≤0.45 |
Mechanical Properties
Minimum values at room temperature unless stated. ReL = yield strength; Rp0.2 = 0.2% proof stress; Rm = tensile strength; A = elongation after fracture.
| Grade | Yield (ReL) | Proof (Rp0.2) | Tensile (Rm) | Elongation A | Impact / others | |
|---|---|---|---|---|---|---|
| Q235B + hot-dip galvanized | — | — | — | — | — | Coating 30–700 g/m² (both sides), made to order Adhesion per GB/T 13912 bend test |
| Q235B | ≥235 MPa | — | 370–500 MPa | ≥26% | +20 °C, ≥27 J | — |
| Q355B | ≥355 MPa (≤16 mm) | — | 470–630 MPa | ≥22% | +20 °C, ≥27 J | — |
Standards & Documents
- GB/T 13912 — hot-dip galvanized coatings on fabricated iron and steel articles
- EN ISO 1461 / ISO 1461 — hot-dip galvanized coatings (international equivalent)
- ASTM A123 / A153 — zinc (hot-dip galvanized) coatings on iron and steel products
- JIS H8641 — hot-dip zinc coatings (Japanese equivalent)
- GB/T 11263 — base H-beam dimensions, shape, mass and tolerance
- Zinc bath to EN 1179 (Zn ≥ 99.995%); coating mass test report with every lot; EN 10204 3.1 mill certificate for the base section
Typical Applications
| Industry / Application | Typical use |
|---|---|
| Coastal & marine structures | Quay and jetty platform frames, fender supports, deck framing and fish-farm structures, where 500 g/m² and heavier coatings are nominated against salt spray. |
| Bridge & footbridge works | Bridge girders, footbridge beams, viewing platforms and boardwalk supports that will never be taken out of service for repainting. |
| Power & substation structures | Substation frames, transmission structure members and equipment supports, with coating weight set by the corrosion class of the site. |
| Water & wastewater plant | Beam supports over tanks, clarifier and settling tank framing, pipe bridges and walkway beams in permanently damp conditions. |
| Chemical & process plant | Pipe rack beams, equipment platforms and support frames in atmospheres where a paint system would need a short renewal cycle. |
| Solar & energy structures | Large ground-mount framing and tracker supports where a 25-year maintenance-free life is expected. |
| Agricultural & food industry buildings | Livestock, poultry and food processing building frames in humid or ammoniacal conditions where wash-down is routine. |
Common Problems Buyers Face — and How We Prevent Them
These are the issues that most often cause claims on steel imports. Each one is controlled in our process before shipment.
White rust on the coating during a long sea voyage
Why it happens: Trapped moisture between bundled beams reacts with the zinc surface, producing wet-storage stain that looks like a coating failure on arrival but is only a surface product.
Our control: Beams are bundled with spacers so air can circulate, shipped dry, with VCI paper on long or humid routes. Chromate passivation is available for appearance-critical orders, and a light white film can be washed off without affecting coating life.
Coating mass below specification on a thick, heavy section
Why it happens: Heavy sections hold more heat, so if dipping time and bath temperature are not matched to the section mass the coating can be thin in some areas.
Our control: Dipping parameters are set for the section mass, jigging is controlled so the profile fills and drains correctly, and coating mass is measured on a sample basis per lot and reported against the specified minimum average.
Site welding burns off the coating at the connection
Why it happens: The fabricated connections are welded on site after galvanizing, leaving bare steel in the highest-stress part of the joint.
Our control: Cutting, drilling and bevelling are carried out before dipping so bolted connections can be used throughout the structure. Where site welding is unavoidable, clean the weld and adjacent zone and apply zinc-rich repair paint, which we can supply with the order.
Coating abraded during loading or unloading
Why it happens: Heavy sections lifted with chains or dragged against each other abrade the coating at flange edges, and each damaged point is where corrosion will begin.
Our control: Beams are lifted with belt or nylon slings at protected contact points, timber separators are placed between layers, the pack is lashed so members cannot rub, and repair material for minor transit damage is supplied with the shipment.
Distortion or bow after galvanizing
Why it happens: The thermal cycle releases rolling stresses, and long slender members are the most sensitive to it, especially narrow-flange beam sections.
Our control: Jigging and dip orientation are controlled, and straightness is checked after galvanizing against the standard for the section. Where a member is distortion-sensitive, tell us at enquiry stage and we will propose a section or an alternative treatment that suits it.
Our Supply & Manufacturing Advantages
- Protection exactly where steel normally corrodes — The coating covers flange edges, bolt holes and the faces of connections — the places where paint is thinnest and inspection is hardest.
- Coating nominated to the exposure class — From 180 g/m² for general outdoor service up to 700 g/m² for severe marine and chemical atmospheres, quoted as the total on both surfaces.
- Mechanical properties unchanged — The galvanizing cycle does not alter yield strength, tensile strength, stiffness or fatigue performance, so the mill certificate for the base section remains valid.
- Processed before dipping — Cut to length, drilled and bevelled to your fabricator's list before galvanizing, so ends and holes are coated and no site rework is needed.
- Documented steel and coating — EN 10204 3.1 mill certificate for the base section plus a coating mass test report, so both the steel and the zinc layer can be verified on arrival.
- Whole-life cost, not first cost — No blasting, priming, painting, inspection or repainting cycle for the life of the structure, which is where the saving is actually realised.
Packaging, Delivery & Payment
- Packing: loose in bulk vessel, or bundled and containerised to your requirement. Galvanized and coated products get VCI paper, waterproof wrapping and edge protection. See our export packaging methods.
- Availability: both stock and custom production. Tell us the specification and we will confirm the route.
- MOQ: no strict minimum — one ton can ship.
- Lead time: stock dispatched to port within 3 days; orders needing export packaging about 1 week; custom production quoted per product.
- Payment: stock — 10% deposit, balance before shipment; custom production — 50% deposit, balance before shipment.
- Documents: EN 10204 3.1 mill test certificate with every shipment; third-party inspection (SGS / BV) on request.
Frequently Asked Questions
What coating weight should I specify for a galvanized H-beam?
For dry indoor service 60 to 100 g/m² is adequate; general outdoor inland exposure is usually 180 to 275 g/m²; coastal and industrial atmospheres 350 to 500 g/m²; and severe marine or chemical exposure 600 to 700 g/m². The figure is the total on both surfaces, equivalent to roughly 7 µm per 100 g/m². Tell us the site conditions and we will nominate the weight.
Does galvanizing change the strength of an H-beam?
No. Hot-dip galvanizing takes place at around 450 °C, which is well below the temperature at which the microstructure and mechanical properties of Q235B or Q355B structural steel would be affected. Yield strength, tensile strength, stiffness and fatigue performance are unchanged, and the mill certificate for the base section continues to apply.
What is the Chinese equivalent of EN S235JR for a galvanized H-beam?
Q235B to GB/T 700 is the base grade closest to S235JR and is the grade we galvanize for the European market, referenced in our library as S235-GALV. For higher strength the base becomes Q355B, the equivalent of S355JR. Both are supplied with the mill certificate and a written grade equivalence.
Can a galvanized H-beam be welded on site?
It can be welded, but the heat destroys the coating in and around the weld and leaves bare steel in the joint. The correct sequence is to weld before galvanizing or to design the connection as bolted. Where site welding is unavoidable, clean the weld and surrounding zone and apply zinc-rich repair paint, and we can supply compatible touch-up material with the order.
Who supplies galvanized H-beams from China for marine and coastal projects?
We supply hot-dip galvanized H-beams across the HW, HM and HN series over Q235B, Q355B and S235-GALV base grades, with coating weight nominated against the exposure class, processing to drawing before dipping and a coating mass test report per lot. Send the section list, the exposure class and the destination port for a quotation.
Is galvanized H-beam more economical than painted H-beam?
The galvanized section costs more per ton, typically adding in the region of 20 to 30 percent once the coating is included, but it removes blasting, priming, painting, inspection and every subsequent repainting cycle. On an outdoor or coastal structure with a design life of 25 years or more, the whole-life cost is normally lower, and where access for maintenance is expensive galvanizing usually wins clearly.
Will the coating be damaged if the beam is drilled or cut on site?
If drilling and cutting are done before galvanizing, which is how we supply processed members, there is no bare steel at all. If material is cut on site after coating, the zinc immediately around the cut will still protect the exposed steel sacrificially, but the cut face should be dressed with zinc-rich repair paint to restore full protection.
Do you have a minimum order quantity?
No strict minimum, and one ton can ship. Because galvanizing is a bath process, small quantities are usually grouped into a load, so we will confirm the real lead time rather than promise an immediate dispatch.
How are galvanized H-beams packed and shipped?
Bundled into stiff packs with timber separators and steel straps sized for container loading, or shipped loose in a bulk vessel. Spacers keep air moving through the pack to avoid wet-storage stain, contact points are protected with timber, and lift points are marked so the coating survives stevedoring.
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