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Carbon Steel Round Bar provides excellent mechanical strength, reliable machinability, and consistent dimensional accuracy for a wide range of engineering and industrial applications. It is widely used in shaft manufacturing, machinery components, structural fabrication, and general mechanical processing.
Suitable for machining, welding, forging, and fabrication, carbon steel round bars deliver dependable performance for construction, manufacturing, and OEM production.
Carbon steel round bar (high-precision solid round steel rod, cold drawn 1018 round bar, 1045 medium carbon steel shafting bar, ASTM A36 structural round bar, Q235/Q355 hot rolled steel round stock, and turned ground & polished TG&P round bar) is produced through continuous hot rolling, precision hydraulic cold drawing, or heavy open-die forging to yield cylindrical solid steel bars. Engineered for high-stress hydraulic cylinder rods, automotive drive axles, transmission gears, precision motor shafts, drill rods, and heavy industrial fasteners, carbon steel round bar offers high tensile strength, outstanding machinability, uniform core toughness, and reliable heat-treatment responsiveness.
At XQJ Metal, we operate advanced continuous hot rolling mills, precision cold drawing benches, centerless grinding machines, and automated heat-treatment induction quenches to manufacture world-class carbon steel round bar products conforming strictly to global engineering standards, including ASTM A108 (cold-finished steel bars), ASTM A29 (general requirements for hot-rolled and cold-finished carbon steel bars), EN 10083 (steels for quenching and tempering), JIS G4051 (S20C/S45C), and DIN 17200 specifications. We supply full diameter options from 6mm to 500mm (1/4″ to 20″), standard lengths from 3m to 12m, and custom cut-to-length cylindrical round bar stock in mill scale, cold drawn bright, centerless ground, and peeled/turned surface finishes.
| Steel Grade Family | Standard Designation & UNS Code | Tensile Strength (MPa) | Yield Strength (MPa) | Hardness (HBW / HRC) | 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 tie rods, anchor bolts, base plates & architectural ironwork |
| Cold Finished Low Carbon | AISI 1018 / UNS G10180 / EN1A / C15 | 440 to 580 MPa | ≥ 370 MPa | 126 to 170 HBW | Tight dimensional tolerances (h9/h11), clean surface finish, high machinability for bushings & pins |
| Medium Carbon Engineering | AISI 1045 / C45 / JIS S45C / Q355B | 570 to 700 MPa | ≥ 345 MPa | 160 to 220 HBW | High fatigue resistance, heat-treatable for induction-hardened shafts, gears, sprockets & crankshafts |
| High-Tensile Alloyed Carbon | AISI 4140 / 42CrMo4 / EN 10083-3 / Q355D | 850 to 1080 MPa | ≥ 685 MPa | 28 to 34 HRC (Q&T) | Exceptional deep hardenability and impact toughness for heavy drill collars, crane axles & studs |
Selecting the optimal processing state for carbon steel round bar depends on diameter tolerance limits, surface roughness requirements, and downstream machining processes:
Machinery builders, automotive suppliers, and metal distribution service centers depend on our customized carbon steel round bar processing services:
Our heavy-duty mechanical and structural carbon steel round bar stock serves as a crucial engineering material across global manufacturing sectors:
To guarantee complete metallurgical consistency and zero surface seam defects, XQJ Metal enforces strict Quality Assurance (QA) protocols on every carbon steel round bar shipment:
Q1: What is the key difference between 1018 and 1045 carbon steel round bar?
A: AISI 1018 is a low carbon steel (0.18% C) with excellent weldability and easy cold forming, ideal for general machined components. AISI 1045 is a medium carbon steel (0.45% C) with higher tensile strength and hardness, making it heat-treatable (induction hardening) for heavy-duty power transmission shafts and gears.
Q2: Can XQJ Metal supply carbon steel round bar with precision TG&P surface finish for hydraulic cylinder rods?
A: Yes, our centerless grinding and polishing mills produce TG&P round bars with outer diameter tolerance down to ISO f7/h8 and surface roughness Ra ≤ 0.2µm, ready for hard chrome plating.
To request current FOB/CIF spot price quotes, steel grade datasheets, or physical sample bars for carbon steel round bar, Contact Our Steel Engineering Team today.
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Carbon steel round bar is designed for components requiring cylindrical geometry, such as shafts, pins, and rollers, while hex bar is better suited for parts requiring wrench flats or reduced machining. The appropriate profile should be selected according to the component design and manufacturing process.
Carbon steel round bar offers excellent versatility for machining, forging, and heat treatment. Its uniform cross-section makes it a preferred raw material for manufacturing a wide range of precision and heavy-duty mechanical components.
Carbon steel round bar is commonly machined into shafts, axles, pins, bushings, rollers, couplings, and other rotating or load-bearing components where strength, dimensional accuracy, and reliable machining performance are required.
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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