Q235B Carbon Steel Flat Bar

Overview of Q235B Carbon Steel Flat Bar

Q235B is one of the most commonly used carbon structural steel flat bar grades in China and the Asia-Pacific region, specified under the Chinese national standard GB/T 700 (Carbon Structural Steels). The designation ‘Q’ represents the yield strength (Qu), ‘235’ indicates the minimum yield strength of 235 MPa, and ‘B’ denotes the quality grade with guaranteed chemical composition, mechanical properties, and Charpy V-notch impact test at 20°C. As a versatile mild steel grade, Q235B offers an excellent balance of adequate strength, good ductility, superior weldability, and outstanding cost-efficiency, making it the workhorse material for general structural fabrication and construction worldwide.

Shandong Tanglu Metal Material Co., Ltd. supplies premium Q235B carbon steel flat bar produced from continuously cast billets or hot-rolled slabs through precision hot rolling processes. Internationally recognized as equivalent to ASTM A36, EN S235JR, JIS SS400, and AS/NZS 3679.1 Grade 250, Q235B flat bar provides B2B buyers with a globally accepted, cost-effective structural steel solution. Available in a comprehensive range of widths (10mm to 300mm) and thicknesses (3mm to 60mm), our Q235B flat bars are widely stocked and ready for rapid dispatch to construction sites, fabrication workshops, and manufacturing facilities worldwide.

Key Features and Technical Advantages

The primary advantage of Q235B carbon steel flat bar is its outstanding weldability — the low carbon content (≤0.20%) and controlled manganese content ensure that flat bars can be joined using all common industrial welding processes (SMAW, GMAW, FCAW, SAW) without preheating, even in thicker sections. This makes Q235B the preferred choice for welded structural frames, brackets, base plates, and general fabrication assemblies.

Q235B flat bar offers excellent cold-forming and hot-forming properties, enabling bending, rolling, punching, shearing, and flame cutting operations without risk of cracking. The flat rectangular cross-section provides high bending stiffness in one direction while maintaining ease of handling, drilling, and bolting. Our flat bars are produced through hot rolling with tight dimensional control on width (±0.8mm to ±2.0mm depending on size), thickness (±0.3mm to ±0.8mm), and straightness (≤3mm per meter).

Available in standard mill lengths of 6m and 12m, with custom cut-to-length service supported. Surface condition is hot rolled black (mill scale) as standard, with shot blasting, primer coating, and hot-dip galvanizing available as value-added services. Every production batch undergoes chemical analysis and mechanical testing per GB/T 700 requirements, ensuring consistent quality for structural safety and engineering reliability.

Main Applications of Q235B Flat Bar

Q235B carbon steel flat bar is the fundamental structural fabrication material used across construction, manufacturing, and infrastructure sectors. In construction, it is extensively used for structural frames, bracing members, column base plates, gusset plates, tie bars, stair stringers, handrail flat bar infills, door and window frames, and reinforcing elements in concrete structures. Its excellent weldability makes it ideal for welded moment connections and built-up structural sections.

In general manufacturing and fabrication, Q235B flat bar serves as raw material for machine bases, equipment frames, mounting brackets, support structures, conveyor frames, shelving systems, and industrial platforms. The agricultural equipment sector uses flat bar for plow blades, harrow tines, trailer frames, and implement structural components. Other applications include fence posts and rails, gate frames, trailer chassis members, truck body structural elements, steel grating support bars, and general-purpose steel shelving and racking.

Hot-dip galvanized Q235B flat bar is widely used for outdoor structures, highway guardrail components, electrical transmission tower bracing, solar panel mounting frames, and marine dock fender systems where long-term corrosion resistance is required in exposed environments.

Why Choose Us for Q235B Carbon Steel Flat Bar

Shandong Tanglu Metal Material Co., Ltd. sources Q235B carbon steel flat bar from major Chinese steel mills holding ISO 9001 certification and utilizing continuous casting and precision hot rolling technology. We maintain strict quality control per GB/T 700 standard, with guaranteed chemical composition (C ≤ 0.20%, Mn ≤ 1.40%), mechanical properties (yield ≥235 MPa, tensile 370-500 MPa), and Charpy impact toughness (≥27J at 20°C for Grade B).

We offer one of the widest size ranges in the industry — widths from 10mm to 300mm and thicknesses from 3mm to 60mm — with standard 6m and 12m lengths and custom cut-to-length service. Value-added processing includes shot blasting, primer painting, hot-dip galvanizing, drilling, punching, and CNC flame/plasma cutting to finished dimensions. With monthly supply capacity of 15,000 tons of flat bar products and extensive export experience to over 60 countries, we provide the volume capability, quality consistency, and competitive pricing required for large-scale construction and manufacturing projects. Each shipment includes original mill test certificate (MTC) per EN 10204 3.1 standard.