China Flat Steel Bar Suppliers and Factory for Structural Supports and General Fabrication
Specification
| Parameter | Range / Options |
|---|---|
| Width | 10 mm – 400 mm (1/2" – 6" in imperial) |
| Thickness | 3 mm – 60 mm (1/8" – 5/8" in imperial) |
| Length | 3 m – 12 m (standard: 6m, 20ft) |
| Popular Sizes | 30×3, 30×5, 40×5, 50×5, 50×8, 50×10, 60×5, 60×8, 60×10, 80×8, 80×10, 100×10, 100×12, 120×10, 150×10 mm |
Material Standards
| Material Type | Standard | Common Grades |
|---|---|---|
| Carbon Steel | ASTM A36 | A36 (structural applications, 36 ksi yield) |
| EN 10025-2 | S235JR (1.0038, formerly St37-2, equivalent to A36) | |
| EN 10025-2 | S355J2 (1.0577, formerly St52-3, equivalent to A572 Grade 50) | |
| JIS G3101 | SS400, SS490 | |
| GB/T 1591 | Q235, Q345 | |
| Stainless Steel | ASTM A276 | 304/L, 316/L |
| EN 10088 | 1.4301, 1.4404 | |
| Spring Steel | ASTM A29 | 5160 |
| Aluminum | EN Standards | EN AW-5083, EN AW-7075 |
Manufacturing Methods
Steel is heated above recrystallization temperature and passed through rolling mills to achieve the desired rectangular cross-section. This is the most common production method for standard flat bars, resulting in a mill-scale surface finish (scale thickness approximately 20–50 μm). Hot rolled flat bars are suitable for general construction and fabrication where surface finish is not critical.
Hot-rolled bars are further processed at room temperature to achieve tighter dimensional tolerances, superior surface finish, and increased strength. Precision flat steel with regular or oversize dimensions is available for applications requiring high dimensional accuracy.
Precision machined edges are deburred and smooth, offering fabrication benefits in terms of component alignment for welding and improved handling. Thermal cut edges are produced by cutting plate into narrower strips for thicker sections.
Surface Finishes
As-rolled with mill scale, typically used for construction and general fabrication.
Clean surface free from mill scale, prepared for painting or further treatment.
Shop-applied primer coating for temporary protection.
Zinc coating applied per ASTM A123 or EN ISO 1461 for corrosion protection. The flat geometry is particularly well suited to galvanizing, providing consistent coverage without hidden surfaces.
Temporary rust protection during transit.
Applications
Flat bars are essential components in structural steelwork for frames, gusset plates, connection brackets, stiffener ribs, and base plates. S355J2 flat bars are widely used for column base plates and beam splice connections where high bearing resistance is required.
Flat bars provide clean lines, smooth surface and mechanical strength required for balustrades, handrails, fence panels, staircases, and ornamental ironwork. They are also used in railing manufacturing and decorative products.
Guide rails, keys, spacer plates, backing strips for welded joints, wear strips, and machine bed levelling shims. The flat cross-section allows precise machining to tight tolerances.
Trailer chassis reinforcement, body-building brackets, equipment mounting plates, agricultural machinery components, and transportation components.
Used in bridge construction, crane sectors, and as main carrier products in building structures. Wide flat bars serve as large stiffener plates, wear liners, and heavy base plates.
Reinforcement strips in concrete formwork, knife bars, clamping bars, hinge straps, furniture making, shipbuilding, railway spare parts, iron towers, boilers, and general workshop stock.