Carbon steel swage-locked grating is a mechanically assembled bar grating in which cross bars are inserted through pre-punched holes in the bearing bars and then hydraulically swaged to form a permanent lock. It is used for walkways, platforms, bridge decks, stair treads, drainage covers, equipment floors, ramps, and architectural access structures. Factory prices depend on the bearing bar profile, bar size, mesh spacing, cross bar type, panel weight, surface finish, quantity, and fabrication requirements. This guide explains how swage-locked grating is made and how manufacturers calculate the price per square meter, panel, or ton.
Carbon steel swage-locked grating is an open steel flooring panel made from parallel bearing bars and cross bars that are mechanically locked together without resistance welding at every intersection. The cross bars pass through holes or slots in the bearing bars. A hydraulic swaging operation deforms the surrounding metal or the cross bar itself so that the members cannot move freely after assembly.
The bearing bars carry the primary load and must run between the structural supports. The cross bars maintain the bar spacing, improve lateral stability, and help distribute local loads. Depending on the product design, cross bars may be flush with the top of the bearing bars, slightly recessed, or positioned at a specified level below the walking surface.
Swage-locked panels provide an open area for drainage, ventilation, heat dissipation, and light transmission. They are often chosen when the project requires a clean mechanical appearance, a regular mesh, or a surface without a visible weld pattern. Carbon steel versions are available in plain or serrated forms and can be supplied bare, painted, or hot-dip galvanized.
| Grating Component | Function | Common Options |
|---|---|---|
| Bearing bars | Carry the main bending load across the clear span | Rectangular flat bar, I-bar, or T-bar |
| Cross bars | Connect the bearing bars and stabilize the panel | Twisted square bar, round bar, or formed bar |
| Pre-punched holes | Receive the cross bars before swaging | Round, diamond, or profile-specific openings |
| Swaged joint | Deforms and locks the cross bar in place | Hydraulic or mechanical cold-forming operation |
| Banding bar | Closes and reinforces exposed or cut panel edges | Flat bar, matching bearing bar, or load-carrying band |
| Perimeter frame | Provides support and protects the panel edge | Angle, channel, flat bar, or fabricated steel frame |
The swage-locking process starts with straight bearing bars and cross bars cut to the required dimensions. The bearing bars are punched at a controlled pitch, and the cross bars are inserted through the prepared openings. The assembled panel is then placed in a swaging machine.
The swaged joint must be tight enough to prevent cross bar rotation, rattling, or progressive movement during service. The pressing force, hole size, cross bar dimensions, and material hardness all influence joint quality. A panel that looks correct from above can still have inadequate mechanical locking if the tooling or pressure is not properly controlled.
Swaging does not normally create a welded heat-affected zone at the intersections. However, perimeter bands, frames, stair nosing, and reinforcement may be welded. If the complete assembly will be galvanized, the order of fabrication and finishing should be agreed with the factory.
Swage-locked, welded, and dovetail pressure-locked grating use different joining methods and are selected for different combinations of load, appearance, material, and cost.
| Feature | Swage-Locked | Welded | Dovetail Pressure-Locked |
|---|---|---|---|
| Connection method | Cross bars inserted and mechanically swaged in pre-punched holes | Cross bars resistance-welded to bearing bars | Rectangular cross bars hydraulically pressed into dovetail slots |
| Typical appearance | Regular mechanical pattern, often flush or recessed | Visible weld pattern and industrial appearance | Clean, uniform, generally weld-free panel field |
| Carbon steel use | Available, but less common than welded steel in some markets | Most common carbon steel production method | Available for architectural and close-mesh applications |
| Load behavior | Depends on bearing bars, cross bars, swage depth, span, and support | Widely documented for industrial and heavy-duty flooring | Must be checked against pressure-locked load data |
| Rolling traffic | Suitable when the surface and bearing bars are designed for wheels | Suitable when engineered for the actual wheel load | Usually selected for pedestrian or appearance-sensitive uses |
| Factory cost | Usually higher than standard welded carbon steel | Generally the lowest-cost high-volume option | Higher machining and hydraulic pressing cost |
Welded grating is often preferred for heavy industrial platforms because resistance welding is fast and the standard load tables are familiar. Swage-locked grating can be attractive when a clean appearance, smooth cross bar arrangement, or specific bearing bar profile is needed. Dovetail grating uses a different slot and cross bar arrangement and should not be treated as interchangeable with swage-locked material.
For a swage-locked panel, the manufacturer’s load table should identify the exact series, bar size, cross bar type, span, and load condition. Similar nominal dimensions do not guarantee the same stiffness or connection capacity.
Swage-locked grating can be produced with several bearing bar profiles. The profile affects stiffness, weight, walking surface, appearance, and manufacturing cost.
| Bearing Bar Profile | Characteristics | Typical Selection |
|---|---|---|
| Rectangular flat bar | Simple geometry, broad availability, easy banding and cutting | General walkways, platforms, drains, and stair treads |
| I-bar | Higher section efficiency and lower weight for some designs | Lightweight platforms and projects requiring higher stiffness-to-weight |
| T-bar | Wide top flange with a formed or narrow lower section | Architectural areas, special drainage designs, or proprietary systems |
| Serrated rectangular bar | Notched top surface for increased traction | Wet, oily, outdoor, inclined, and process areas |
| Serrated I-bar | Slip-resistant top combined with an efficient structural profile | Lightweight industrial walkways and ramps |
Rectangular bars are the easiest to compare with ordinary welded grating. I-bars and T-bars require product-specific load data because their section properties and local behavior differ from flat bars. The top flange width also affects heel safety, wheel contact, and the fit of edge bands or stair nosing.
Bearing bar height and thickness are the primary dimensions used to select the load capacity of a swage-locked panel. Typical carbon steel examples include 25 × 3 mm, 30 × 3 mm, 30 × 5 mm, 32 × 5 mm, 40 × 5 mm, and 50 × 5 mm. Heavier bridge or vehicle panels may use substantially larger sections.
| Bearing Bar Example | General Service Position | Possible Application |
|---|---|---|
| 25 × 3 mm | Light-duty and short-span | Indoor walkways, guards, and light access panels |
| 30 × 3 mm | Standard-duty | General platforms and industrial walkways |
| 30 × 5 mm | Medium-duty | Equipment platforms, ramps, and longer spans |
| 32 × 5 mm | Medium to heavy-duty | Service decks and higher concentrated loads |
| 40 × 5 mm | Heavy-duty | Industrial floors and demanding platform spans |
| 50 × 5 mm or larger | Very heavy-duty | Vehicle paths, bridge decks, and high point loads |
Common bearing bar spacing includes approximately 19, 25, 30, 38, and 40 mm. In imperial designations, a 19-S-4 pattern generally indicates bearing bars on approximately 1-3/16-inch centers and cross bars on 4-inch centers. A closer 19-S-2 pattern uses the same approximate bearing bar spacing with cross bars on 2-inch centers.
Closer bearing bar spacing reduces the opening and places more bars beneath a foot, wheel, or point load. It also increases the number of bars, steel weight, pressing time, and factory price. A wider spacing uses less material and provides more open area, but it may not satisfy heel safety, small-wheel, or tool-retention requirements.
More information about bar size, pitch, panel dimensions, and tolerance control is available in this steel bar grating dimensions guide.
Twisted square and round cross bars are the most common options for swage-locked grating. The choice affects the appearance, joint design, surface profile, drainage, and material consumption.
| Cross Bar Type | Advantages | Typical Consideration |
|---|---|---|
| Twisted square bar | Traditional grating appearance and strong visual pattern | Common for industrial walkways and platforms |
| Round bar | Smoother profile and simple rolling contact | Requires correct hole and swage design |
| Flat or rectangular bar | Broad contact area and clean architectural appearance | Higher material use and more specialized tooling |
| Formed or proprietary bar | Can be optimized for stiffness, drainage, or appearance | May require dedicated dies and a higher minimum order |
Common cross bar sizes include approximately 5, 6, 8, and 10 mm for round or twisted square bars, while larger sections may be used for heavy-duty products. Cross bar spacing is often 50 or 100 mm, with 75 mm available in some production systems.
A cross bar is not automatically a primary load member simply because it is thick. The bearing direction and support arrangement remain critical. A load placed between two bearing bars may be shared through the cross bars, but the exact amount of distribution depends on the grating construction and the load type.
Swage-locked grating is available in close, standard, and more open mesh patterns. The best choice depends on foot safety, drainage, ventilation, wheel size, debris, and load capacity.
| Mesh Example | Approximate Arrangement | Typical Use |
|---|---|---|
| 11-S-4 | Approximately 17.5 mm bearing bar pitch × 100 mm cross bar pitch | Close mesh, small wheels, public walking surfaces, and tool retention |
| 19-S-4 | Approximately 30 mm × 100 mm | General industrial walkways and platforms |
| 19-S-2 | Approximately 30 mm × 50 mm | Closer cross bars for carts and smaller objects |
| 30 × 100 mm | Metric general-purpose pattern | Platforms, catwalks, and service flooring |
| 30 × 50 mm | Metric close cross-bar pattern | Pedestrian areas and small-wheel traffic |
| 40 × 100 mm | More open metric pattern | Ventilation, drainage, and areas without small-wheel concerns |
Nominal pitch is not the same as clear opening. The clear opening is reduced by the bearing bar thickness, cross bar profile, and the exact hole arrangement. Suppliers should provide the clear opening on the drawing when heel safety, wheelchair access, small wheels, or object retention is important.
Open area is the percentage of the panel occupied by openings. Larger open area reduces weight and improves drainage, ventilation, and light transmission. Smaller open area provides a more continuous walking surface but normally increases steel consumption and price.
Swage-locked grating must be selected for the actual clear span and load. The bearing bars should span from one support to the next, and the stronger direction of the panel should be identified on the shop drawing.
The main design inputs are:
Clear span is the unsupported distance between the bearing supports. It is not the overall length of the panel. A 6,000 mm-long panel can have intermediate support beams and a clear span of only 1,000 mm. A shorter panel may need much deeper bars if it bridges a large opening.
| Load Condition | Example | Design Concern |
|---|---|---|
| Uniform pedestrian load | Workers distributed over the walkway | Overall bending, deflection, and vibration |
| Concentrated foot load | One worker standing in an unfavorable position | Local bending and load sharing |
| Equipment point load | Motor, pump, valve actuator, or support foot | Local reinforcement and support location |
| Maintenance cart | Small wheels carrying tools or components | Clear opening, wheel spacing, and point load |
| Forklift load | Forklift wheels and pallet load | Heavy-duty bearing bars, impact, and support spacing |
| Vehicle load | Service vehicle or bridge traffic | Vehicle class, fatigue, wheel path, and structural framing |
Published load tables for swage-locked products may list uniform and concentrated loads at defined spans. They are valid only for the stated grating series, bearing bar size, cross bar arrangement, support condition, and deflection criterion. Data for aluminum swage-locked grating should not be applied to carbon steel without confirmation.
Deflection can govern before the steel reaches its ultimate strength. Excessive movement may cause uncomfortable walking, vibration, loose fasteners, damage to equipment, or water accumulation. Project requirements may use limits such as L/200, L/240, or a maximum millimeter value, but the governing criterion should come from the owner or structural engineer.
Plain grating has smooth bearing bar tops and is often preferred for dry floors, rolling equipment, and areas where cleaning is important. Serrated grating has notches or teeth along the bearing bars and is selected where improved traction is needed.
| Feature | Plain Swage-Locked Grating | Serrated Swage-Locked Grating |
|---|---|---|
| Surface profile | Smooth bearing bar top | Notched or toothed bearing bar top |
| Wheel movement | Generally smoother for carts and dollies | May create more surface vibration for small wheels |
| Pedestrian traction | Suitable for dry and controlled areas | Better for wet, oily, muddy, or icy areas |
| Cleaning | Easier to sweep and wash | May retain more dirt in the serrations |
| Price | Lower for the same bar and mesh | Higher because of serration processing |
Serrated bearing bars may require a different load-table selection because the notches reduce part of the effective top section. The factory should confirm whether the next greater bar depth is required for the specified load.
Serrated grating is not automatically slip-proof. Footwear, surface contamination, slope, drainage, lighting, housekeeping, and handrails also affect safety. Where a project requires a particular anti-slip classification, that requirement should be stated in the purchase documents.
Mill-finish or bare carbon steel is normally the lowest-cost option. It is suitable for indoor structures, temporary platforms, or projects where a separate coating will be applied after installation. Bare steel can develop surface oxidation during storage if it is exposed to moisture.
Painted grating may use a shop primer, epoxy, polyurethane, powder coating, or another approved system. The cost depends on surface preparation, coating type, film thickness, color, curing, and inspection.
Paint is useful for indoor corrosion protection and color identification, but it can be damaged by wheels, tools, impact, and aggressive chemicals. The service environment and maintenance plan should be evaluated before using paint as the only protection.
Hot-dip galvanizing is normally carried out after swaging, cutting, banding, framing, and inspection. The completed panel is cleaned and immersed in molten zinc so that the bearing bars, cross bars, edges, and fabricated accessories receive protection together.
Post-fabrication galvanizing usually gives better coverage to cut edges and accessory welds than fabricating from pre-galvanized material. If a galvanized panel is cut or welded after delivery, the exposed area requires an approved zinc repair system.
Project specifications may reference ASTM A123/A123M, ISO 1461, or another local standard. Coating requirements depend on steel thickness, exposure, surface preparation, and the selected standard. Zinc shade can vary from bright to dull gray, and color uniformity alone does not determine coating performance.
| Finish | Price Position | Typical Use |
|---|---|---|
| Bare steel | Lowest | Indoor, protected, or separately coated structures |
| Shop-painted steel | Low to medium | Indoor platforms and color-finished projects |
| Hot-dip galvanized steel | Medium to high | Outdoor walkways, platforms, bridge decks, and humid plants |
| Duplex galvanized and painted | High | Severe exposure and long maintenance intervals |
Common swage-locked panel dimensions depend on the manufacturer’s machine width, bearing bar count, cross bar length, and handling equipment. Typical stock formats include 2 or 3 ft widths with 20 or 24 ft lengths in imperial markets, and approximately 600 × 2,000 mm, 750 × 3,000 mm, 1,000 × 3,000 mm, or 1,000 × 6,000 mm in metric production.
| Panel Format | Typical Application | Handling or Cost Consideration |
|---|---|---|
| 600 × 2,000 mm | Compact access routes and removable covers | Easy handling and low lifting weight |
| 750 × 3,000 mm | Narrow industrial walkways and ramps | Efficient for service routes |
| 1,000 × 3,000 mm | Platforms and equipment floors | Convenient modular layout |
| 1,000 × 6,000 mm | Long catwalks and bridge sections | Fewer joints but greater lifting and shipping weight |
| 2 or 3 ft × 20 or 24 ft | Imperial industrial layouts | Width may be based on bearing bar count |
Stock panels usually have the shortest lead time and the lowest setup cost. Cut-to-size panels can still be economical when several pieces can be nested from one standard panel. Many different dimensions, narrow strips, irregular angles, and small pieces increase sorting, marking, and inspection work.
Panel tolerances normally cover overall length and width, squareness, flatness, bearing bar pitch, cross bar position, and cutout location. A custom width may leave a slightly different edge opening because the pattern is based on a fixed number of bearing bars. The final shop drawing should show the finished outside dimensions and the edge condition.
Custom fabrication is often needed around columns, pipes, tanks, ladders, cable trays, equipment, drains, and access hatches. These operations add cutting, layout, deburring, handling, inspection, and sometimes welding.
Banding closes exposed bearing bar ends and provides a cleaner, stronger edge. It may be required at cutouts, stair tread ends, removable panels, and edges supported on narrow angles.
A load-carrying band can transfer local forces around an opening, but it does not replace the structural beam needed beneath a large penetration. The band size and weld detail should be shown on the drawing.
Cutouts around pipes, columns, valves, motors, cable trays, and drainage outlets should be dimensioned from two panel edges. The drawing should include the opening size, corner radius, edge banding, and support arrangement.
Cutting through several bearing bars can reduce local capacity. The factory may recommend a banded edge, an angle frame, additional bearing bars, or a separate support member. Irregular cutouts generally cost more than straight trimming because they require CNC programming and create more scrap.
Swage-locked grating can be fabricated into stair treads with front nosing, side plates, bolt holes, end angles, and serrated bearing bars. Tread depth, support width, nosing projection, rise-and-run geometry, and concentrated foot load should be included in the RFQ.
Drain covers require accurate fit, adequate open area, removable access, and a load rating for pedestrians, carts, forklifts, or vehicles. A standard walkway panel should not be used as a traffic-rated drain cover without a wheel-load calculation.
Panel weight is one of the main factors in factory pricing. It affects the cost of carbon steel, punching, swaging, galvanizing, lifting, packaging, container loading, and freight.
A preliminary estimate for the bearing bar portion is:
Bearing-bar weight approximately equals 7.85 × bar height × bar thickness ÷ bearing-bar pitch.
When dimensions are entered in millimeters, the result is approximately kilograms per square meter for the bearing bars. Cross bars, holes, bands, frames, serration, and coating must then be added.
For example, a 30 × 5 mm flat bearing bar at a 30 mm pitch contributes approximately 39.25 kg/m² before cross bars and edge components. With 8 × 8 mm cross bars at 100 mm spacing, the finished panel may weigh approximately 44–52 kg/m², depending on the exact swage geometry and banding.
| Grating Category | Indicative Weight Range | General Price Effect |
|---|---|---|
| Light-duty 25 × 3 mm class | Approximately 20–30 kg/m² | Lower material and handling cost |
| Standard-duty 30 × 3 mm class | Approximately 25–36 kg/m² | Common industrial price range |
| Medium-duty 30 × 5 mm class | Approximately 40–55 kg/m² | Higher stiffness and steel consumption |
| Heavy-duty 40 × 5 mm class | Approximately 50–70 kg/m² | Higher steel, zinc, and shipping cost |
| Close-mesh or framed panel | Often above the basic bar-weight range | More bars, cross material, banding, and fabrication |
These figures are planning ranges only. Actual weight changes with I-bar or T-bar profiles, cross bar diameter, spacing, panel width, edge bands, cutouts, and manufacturing tolerances. The factory should provide the approved net weight and the final gross packed weight.
Swage-locked grating can be quoted by square meter, square foot, panel, kilogram, or metric ton. The quotation basis should be clarified before comparing suppliers.
| Quotation Unit | Best Use | What to Confirm |
|---|---|---|
| Per square meter | Platforms, walkways, and project quantities | Gross panel area or net finished area |
| Per panel | Standard stock panels | Exact dimensions, weight, mesh, and included fabrication |
| Per metric ton | Large-volume industrial orders | Steel weight basis, swaging labor, scrap, coating, and packing |
| Per kilogram | Custom or weight-based factory calculations | Weight before or after galvanizing and fabrication |
The following ranges are broad EXW or FOB factory budgeting references for normal export inquiries. They are not fixed market prices or firm offers. Steel costs, production location, quantity, tooling, finish, and delivery terms can move the final quotation outside these ranges.
| Product Type | Indicative Factory Price | Typical Conditions |
|---|---|---|
| Bare standard-duty rectangular swage-locked grating | Approximately US$45–85/m² | Plain surface, regular mesh, standard panel sizes |
| Bare serrated swage-locked grating | Approximately US$55–105/m² | Serrated bearing bars and standard production quantity |
| Painted carbon steel swage-locked grating | Approximately US$55–115/m² | Shop primer or basic paint system |
| Hot-dip galvanized standard grating | Approximately US$70–140/m² | Galvanizing after assembly and regular edge treatment |
| Heavy-duty or close-mesh grating | Approximately US$95–200/m² | Thicker bars, closer spacing, and higher load requirements |
| Custom framed or vehicle-rated panels | Approximately US$130–300+/m² | Wheel loads, cutouts, frames, testing, and project fabrication |
A 1,000 × 2,000 mm panel covers approximately 2 m². At US$70–140/m², a standard galvanized panel may be approximately US$140–280 before clips, cutouts, packaging, and delivery. A 1,000 × 3,000 mm panel covers approximately 3 m² and may be approximately US$210–420 at the same rate.
For a ton-based comparison, divide the square-meter price by the net weight in metric tons per square meter. If a panel weighs 50 kg/m² and costs US$100/m², the equivalent value is approximately US$2,000 per metric ton. This conversion is only a comparison tool; the factory’s ton quotation may include separate allowances for scrap, swaging, coating, labor, and packing.
For additional cost terminology and quotation methods, buyers can review this steel grating factory price guide.
| Cost Factor | Effect on the Price |
|---|---|
| Bearing bar profile | I-bars and T-bars may require specialized tooling and different material consumption |
| Bearing bar height and thickness | Larger sections increase steel weight, handling, and fabrication time |
| Bearing bar pitch | Closer spacing increases the number of bars and reduces the opening |
| Cross bar type | Twisted, round, and formed bars have different material and processing costs |
| Cross bar spacing | Closer spacing increases material consumption and assembly time |
| Plain or serrated surface | Serration adds cutting, forming, and inspection operations |
| Load rating | Higher loads require larger bars, closer supports, or reinforced panels |
| Panel layout | Irregular sizes and many small panels increase setup, marking, and sorting |
| Cutouts and notches | CNC cutting, deburring, scrap, and banding add fabrication charges |
| Surface treatment | Paint, galvanizing, duplex coating, and special preparation add processing cost |
| Quantity and MOQ | Large repeat orders spread setup and tooling cost over more panels |
| Packaging and shipping | Heavy bundles require stronger skids, protection, and careful container loading |
Riveted, welded, and pressure-locked prices should only be compared after normalizing the load capacity, weight, finish, and fabrication. A lighter panel may look cheaper per square meter but require additional support beams or more frequent replacement in service.
A complete RFQ should give the factory enough information to calculate the panel weight, production method, load capacity, fabrication, and delivery cost.
| Information to Provide | Example or Question |
|---|---|
| Grating type | Swage-locked, mechanically locked cross bars |
| Material grade | ASTM A36, ASTM A1011, Q235B, S235JR, or approved equivalent |
| Bearing bar profile | Rectangular flat bar, I-bar, T-bar, or serrated profile |
| Bearing bar size | Height × thickness, such as 30 × 5 mm |
| Bearing bar pitch | 19, 25, 30, 38, or 40 mm; or an imperial series |
| Cross bar | Twisted square, round, formed, size, and spacing |
| Surface | Plain or serrated |
| Panel dimensions | Length, width, quantity, and tolerance |
| Load requirements | Uniform, concentrated, wheel, forklift, vehicle, and equipment loads |
| Support information | Clear span, support width, bearing direction, and frame type |
| Fabrication | Cutouts, notches, banding, frames, stair nosing, holes, and hinges |
| Finish | Bare, painted, hot-dip galvanized, or duplex coating |
| Documents | Mill certificate, load table, dimensional report, and coating report |
| Delivery details | MOQ, lead time, packing, destination, and Incoterm |
A marked-up layout or panel schedule should identify each panel number, finished size, bearing direction, support location, cutout, banded edge, and accessory. This allows the factory to optimize material yield and produce a complete quotation.
For replacement work, include photographs and measurements of the existing panel, but do not rely on photographs alone. Bearing bar profile, cross bar position, swage detail, panel width, and support clearance must be matched accurately.
How much does carbon steel swage-locked grating cost per square meter?
As a broad 2026 factory budgeting reference, bare standard-duty swage-locked grating may cost approximately US$45–85/m², painted products approximately US$55–115/m², hot-dip galvanized products approximately US$70–140/m², and heavy-duty or close-mesh panels approximately US$95–200/m². Custom framed or vehicle-rated panels can exceed US$300/m². The final price depends on bar size, profile, mesh, weight, quantity, finish, fabrication, and delivery.
Is swage-locked grating suitable for heavy loads?
It can be suitable when the exact bearing bar, cross bar, swage connection, span, support, and load condition are engineered correctly. Heavy equipment, forklift, and vehicle applications require a manufacturer’s load table or structural calculation. A standard light-duty swage-locked panel should not be used for high wheel loads simply because it has a mechanically locked joint.
What is the difference between swage-locked and welded grating?
Swage-locked grating uses cross bars inserted through pre-punched bearing bar holes and mechanically deformed into a permanent lock. Welded grating fuses the cross bars to the bearing bars at the intersections. Welded carbon steel is usually more economical for high-volume industrial flooring, while swage-locked grating is often selected for a clean mechanical appearance, special profiles, or a particular surface and mesh design.
