Steel flat bars are among the most versatile and widely used steel products in construction, fabrication and industrial manufacturing across Europe. ULAMEX supplies a comprehensive range of hot rolled flat bar steel in widths from 20 mm to 200 mm and thicknesses from 5 mm to 20 mm, manufactured from non-alloy structural carbon steel to the highest European standards. For heavy-duty structural applications, we also stock wide flat bar steel in widths from 150 mm to 400 mm, providing the broader cross-sections needed for base plates, stiffener plates and large-scale fabrication. With over 38 years of experience as a steel flat bar supplier, ULAMEX maintains extensive stock of the most popular flat bar sizes for immediate dispatch across the United Kingdom, Scandinavia, Benelux and the wider European market.
Material Grades and Standards for Steel Flat Bars
Our steel flat bars are produced in accordance with EN 10058, the European standard governing hot rolled flat steel bars for general purposes, including dimensions, tolerances and technical delivery conditions. All material grades conform to EN 10025-2, the principal European material specification for non-alloy structural steels. We stock two grades that cover the vast majority of construction and fabrication requirements:
- S235JR (material number 1.0038, formerly St37-2, equivalent to ASTM A36) — the most widely specified mild steel flat bar grade for general construction and fabrication. Minimum yield strength of 235 MPa (for thicknesses up to 16 mm), tensile strength of 360–510 MPa and minimum elongation of 26%. The “JR” designation guarantees Charpy V-notch impact toughness of 27 J at +20°C, making S235JR suitable for moderate-climate applications including frames, brackets and general steelwork.
- S355J2 (material number 1.0577, formerly St52-3, equivalent to ASTM A572 Grade 50) — a higher-strength structural steel with minimum yield strength of 355 MPa, tensile strength of 470–630 MPa and guaranteed impact toughness of 27 J at −20°C. S355J2 flat bar steel is the preferred choice for load-bearing structural connections, gusset plates in steel frames, heavily loaded brackets and applications where weight savings through reduced cross-sections are advantageous.
Both grades offer excellent weldability with carbon equivalent values (CEV) well below 0.45, permitting standard arc welding processes (MIG/MAG, MMA, TIG) without mandatory preheat for thicknesses up to 25 mm. For projects requiring documented chemical composition and mechanical properties, we supply EN 10204 Type 3.1 inspection certificates with full mill test results.
Dimensions, Tolerances and Specifications
ULAMEX stocks steel flat bar sizes across a wide dimensional range to meet diverse project requirements. Our standard flat bar programme covers:
- Standard flat bars (EN 10058): width 20–200 mm, thickness 5–20 mm
- Wide flat bars (EN 10025-2): width 150–400 mm, thickness 5–40 mm
- Standard length: 6,000 mm (6 m)
- Popular cross-sections: 30×3, 30×5, 40×5, 40×8, 50×5, 50×8, 50×10, 60×5, 60×8, 60×10, 80×8, 80×10, 100×10, 100×12, 120×10, 150×10, 150×15, 200×20 mm
Dimensional tolerances conform to EN 10058 for standard flat bars. Width tolerances range from ±1.0 mm (for widths up to 50 mm) to ±2.0 mm (for widths above 150 mm). Thickness tolerances are typically ±0.5 mm to ±1.0 mm depending on section size. Straightness deviation does not exceed 0.5% of the bar length. The weight per metre of a steel flat bar is calculated from the cross-sectional area multiplied by the density of steel (7,850 kg/m³). For example, a 50×10 mm flat bar weighs approximately 3.93 kg/m, while a 100×12 mm flat bar weighs approximately 9.42 kg/m. Custom cutting to length is available on request.
Applications of Steel Flat Bars
Steel flat bars are indispensable components in an exceptionally broad range of industries and construction disciplines. Their rectangular cross-section provides high stiffness in one plane while remaining easy to cut, drill, weld and form, making them the preferred choice for both structural and decorative applications:
- Steel construction and fabrication — Flat bar for frames, gusset plates, connection brackets, stiffener ribs and base plates in structural steelwork. S355J2 flat bar is widely used for column base plates and beam splice connections where high bearing resistance is required.
- Gates, railings and fencing — Steel flat bar for gates and flat bar for fencing are among the most popular applications. Flat bar provides the clean lines, smooth surface and mechanical strength required for balustrades, handrails, fence panels and ornamental ironwork.
- Machine building and manufacturing — 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.
- Transport and agriculture — trailer chassis reinforcement, body-building brackets, equipment mounting plates and agricultural machinery components.
- Miscellaneous fabrication — reinforcement strips in concrete formwork, knife bars, clamping bars, hinge straps and general workshop stock. Wide flat bar is additionally used for large stiffener plates, wear liners and heavy base plates.
The clean rectangular profile and consistent cross-section of hot rolled flat bar make it one of the most efficient shapes for transmitting load across a connection, distributing stress over a wider area and reducing localised stress concentrations at bolted or welded joints.
Technical Properties of Steel Flat Bars
The mechanical and physical properties of our steel flat bars make them suitable for a wide spectrum of structural and fabrication tasks. Key technical characteristics include:
- Yield strength: 235 MPa (S235JR) or 355 MPa (S355J2) for thicknesses up to 16 mm
- Tensile strength: 360–510 MPa (S235JR) or 470–630 MPa (S355J2)
- Elongation at break: minimum 26% (S235JR) or 22% (S355J2)
- Density: 7,850 kg/m³
- Modulus of elasticity: 210,000 MPa (210 GPa)
- Thermal expansion coefficient: 12 × 10⁻⁶ /°C
Weldability is excellent for both grades. S235JR flat bars can be welded with all standard arc welding methods without preheat. S355J2 flat bars may require preheat above 100°C for thicknesses exceeding 25 mm or in ambient temperatures below 5°C, in accordance with EN 1011-2. For critical structural connections designed to EN 1090 Execution Class 2 or higher, welding procedure specifications (WPS) must be qualified per EN ISO 15614-1.
Hot rolled flat bar steel has a mill-scale surface finish (scale thickness approximately 20–50 µm). For corrosion protection, flat bars can be blast-cleaned to Sa 2.5 and painted, hot-dip galvanised to EN ISO 1461, or powder-coated. The flat geometry is particularly well suited to surface preparation and coating, providing consistent coverage without the hidden surfaces found in enclosed profiles.
Quality Assurance and Certification
ULAMEX operates under EN 1090-1 factory production control and ISO 3834-2 quality management, ensuring consistent quality throughout the supply chain from mill to delivery. Every batch of steel flat bar is traceable to the producing mill and supplied with full material documentation. We provide EN 10204 Type 3.1 inspection certificates confirming chemical composition, mechanical properties and dimensional compliance. Our certifications demonstrate our commitment to delivering steel products that meet the exacting requirements of European construction standards, CE marking directives and site-specific quality plans.
Ordering and Delivery
Our most popular steel flat bar sizes are maintained in stock for rapid availability. Standard lead time for stock items is 2–5 working days across Europe, with express delivery options for urgent requirements. For non-standard dimensions, special lengths or large project quantities, we offer competitive lead times from our mill partners. All flat bars are bundled and strapped for safe handling and delivered on full-length vehicles or cut to transport-friendly lengths as required.
To request a quotation for steel flat bars, wide flat bars or any product from our black steel rods range, please contact our sales team. We provide detailed technical advice, competitive wholesale pricing and reliable pan-European logistics — backed by over 35 years of experience in the steel distribution industry.