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Carbon Steel Square Bar provides excellent mechanical strength, dimensional consistency, and reliable fabrication performance for structural and engineering applications. Its square profile offers enhanced stability and versatility, making it suitable for welding, machining, and general metal fabrication.
Widely used in structural frameworks, support systems, machinery, construction projects, and OEM manufacturing requiring durable and cost-effective steel materials.
Carbon steel square bar (high-strength solid square steel rod, cold drawn A36 square bar, AISI 1018 low carbon square bar, 1045 medium carbon steel square key stock, Q235/Q355 structural square bar, and hot rolled steel square bar) is manufactured through hot rolling, precision cold drawing, or heavy forging processes to yield solid square-profile solid steel bars with square cross-sections. Engineered for heavy structural frameworks, machine tool guides, shaft keys, agricultural equipment, conveyor systems, and architectural grilles, carbon steel square bar provides uniform dimensional consistency, superior yield strength, excellent weldability, and reliable metalworking machinability.
At XQJ Metal, we operate advanced continuous hot rolling mills, precision hydraulic cold drawing benches, centerless grinding machines, and automated heat-treatment furnaces to manufacture world-class carbon steel square bar products conforming strictly to global engineering standards, including ASTM A36 (carbon structural steel), ASTM A108 (cold-finished steel bars), EN 10025 (non-alloy structural steels), JIS G3101 (SS400), and DIN 17100 specifications. We supply full square side dimension options from 6mm x 6mm to 150mm x 150mm (1/4″ to 6″), standard lengths from 3m to 12m, and custom cut-to-length solid square profiles in mill scale, cold drawn bright, and shot-blasted surface finishes.
| Steel Grade Family | Standard Designation & UNS Code | Tensile Strength (MPa) | Yield Strength (MPa) | Hardness (HBW / HRB) | Primary Engineering Attributes |
| Low Carbon Structural | ASTM A36 / Q235B / EN S235JR / JIS SS400 | 400 to 550 MPa | ≥ 235 MPa | 119 to 159 HBW | Outstanding weldability, structural frameworks, general fabrication, support beams & grilles |
| Cold Finished Low Carbon | AISI 1018 / UNS G10180 / EN1A / C15 | 440 to 580 MPa | ≥ 370 MPa | 126 to 170 HBW | Tight dimensional tolerances, clean smooth surface finish, high machinability for gears & keys |
| Medium Carbon Engineering | AISI 1045 / C45 / EN10083 C45E / Q355B | 570 to 700 MPa | ≥ 345 MPa | 160 to 220 HBW | High fatigue resistance, heat-treatable for hardened machine shafts, pins, sprockets & couplings |
| High-Strength Alloyed Carbon | ASTM A572 Gr.50 / Q355D / S355J2 | 470 to 630 MPa | ≥ 355 MPa | 150 to 200 HBW | Enhanced low-temperature impact toughness, heavy crane structures & mining equipment supports |
Selecting between cold drawn and hot rolled carbon steel square bar depends on dimensional tolerance limits, surface finish aesthetic requirements, and machining operations:
Construction engineers, machinery manufacturers, and metal service centers rely on our customized carbon steel square bar processing services:
Our structural and mechanical carbon steel square bar products are widely utilized across global heavy industries:
To guarantee complete metallurgical integrity and mechanical reliability, XQJ Metal enforces strict Quality Assurance (QA) protocols on every carbon steel square bar consignment:
Q1: What is the main difference between A36 and AISI 1018 carbon steel square bar?
A: ASTM A36 is a hot-rolled structural steel standard focusing on minimum yield strength (235 MPa) and weldability, ideal for building framing. AISI 1018 is a cold-drawn carbon steel grade focusing on tight dimensional tolerances, smooth surface finish, and consistent machinability for shaft keys and turned components.
Q2: Can XQJ Metal supply carbon steel square bar in non-standard metric and fractional inch sizes?
A: Yes, our cold drawing and hot rolling lines can furnish both standard metric square sizes (e.g., 10x10mm, 12x12mm, 20x20mm, 50x50mm) and fractional inch square sizes (e.g., 1/2″, 3/4″, 1″, 2″, 3″, 4″) tailored to project specifications.
To request current FOB/CIF spot price quotes, steel grade datasheets, or physical sample bars for carbon steel square bar, Contact Our Steel Engineering Team today.
Our materials support a wide range of construction and infrastructure projects
Carbon steel square bar features flat surfaces and sharp corners that simplify positioning, fastening, and fabrication, while round bar is better suited for rotating and cylindrical components. The appropriate profile should be selected according to the part geometry and manufacturing requirements.
Carbon steel square bar provides flat contact surfaces that make cutting, welding, drilling, and assembly more efficient. Its profile helps improve alignment and fabrication accuracy in a wide range of structural and industrial applications.
Carbon steel square bar is widely used to manufacture support frames, brackets, keys, guide blocks, machine bases, tooling components, and other fabricated parts that require reliable strength, dimensional stability, and straightforward machining.
It offers excellent resistance to seawater corrosion and maintains strength in humid and salt-rich conditions.
No. Strength is achieved through strain hardening rather than heat treatment.
Yes. It provides excellent weldability for structural fabrication.
Yes, it is commonly applied in tanks and pressure equipment.
Yes. It provides higher strength compared with most non-heat-treated aluminum alloys.
Yes. Thickness, width and temper can be adjusted based on project demand.
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