Product Overview
Carbon steel square bars are solid hot-rolled or cold-drawn steel profiles featuring 90-degree sharp or slightly rounded corners. Engineered for high tensile strength, machinability, and structural rigidity, our square bars serve as primary raw materials for OEM component manufacturing, heavy equipment frames, and structural frameworks. Produced in standard metric and imperial dimensions, strictly adhering to ASTM, EN, JIS, and GB standards.
Technical Specifications & International Grade Equivalents
|
Parameter |
Standard / Specification |
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Material Grades & Equivalents |
USA (AISI/ASTM): 1018, 1020, 1045, 4140 Europe (EN/DIN): C10E, C22E, C45, 42CrMo4 (1.1191, 1.7225) China (GB): Q235, Q355, 45#, 42CrMo Japan (JIS): S20C, S45C, SCM440 |
|
Executive Standards |
ASTM A29, EN 10083, JIS G4051, GB/T 699 |
|
Size Range |
10 mm x 10 mm to 150 mm x 150 mm (Custom sizes available upon request) |
|
Length Options |
Standard 3m, 5.8m, 6m, or cut-to-length (Tolerance: +/- 5 mm) |
|
Surface Finish |
Hot-rolled black, Cold-drawn bright, Turned & Polished, Peeled |
|
Straightness |
<= 1.5 mm/m (Precision grade available up to <= 0.75 mm/m) |
|
Delivery Condition |
As-rolled, Normalized, Annealed, or Quenched & Tempered (Q&T) |
Product Advantages
Tight Dimensional Tolerances:
Cold-drawn variants maintain strict cross-sectional tolerances (+/- 0.03 mm to +/- 0.10 mm), reducing subsequent CNC machining allowances and material waste.
Uniform Mechanical Properties:
Continuous billet casting and controlled rolling temperature profiles ensure homogeneous hardness and tensile strength across the entire cross-section.
Optimal Machinability:
Balanced carbon content in structural and alloy grades (such as AISI 1045 and 4140 equivalents) allows efficient chip breaking and extended tool life during milling and turning operations.
Reliable Weldability:
Low-carbon variants (AISI 1018/1020 equivalents) exhibit excellent arc welding performance without requiring complex pre-heating procedures.
Applications
Machined Components: Shafts, pins, keys, bolts, and spindles produced via CNC turning and milling centers.
Industrial Machinery: Structural chassis, machine bed reinforcements, safety guards, and conveyor guide rails.
Construction & Infrastructure: Brackets, base plates, lintels, and architectural metalwork.
Automotive & Agriculture: Hitch pins, steering linkages, chassis stiffeners, and implement frames.
Customization & Processing
High-precision bandsaw cutting for exact cut-to-length requirements, eliminating on-site scrap for end-users.
Shot blasting, anti-rust oil coating, passivation, or primer painting available based on storage and exposure requirements.
In-house and partner furnace facilities capable of annealing, normalizing, and quenching & tempering to meet targeted hardness or tensile specifications.
Quality Control & Inspection
Chemical Composition Verification: Spectrometer analysis conducted on every heat melt to confirm carbon, manganese, silicon, sulfur, and phosphorus limits match mill test certificates (MTC).
Dimensional Inspection: 100% Vernier caliper and micrometer checks on sampled bars per batch; laser straightness verification for long bars utilizing multi-roll straightening equipment.
Defect Detection: Ultrasonic testing available upon request to identify internal micro-voids, inclusions, or core segregation in critical engineering grades.
Traceability: Heat numbers and grade codes are stamped or tagged on bundles, matching directly to EN 10204 3.1 Mill Test Certificates provided prior to shipment.
Packaging & Shipping
Bundle Configuration:
Securely strapped with high-tensile steel bands in hexagonal or square bundles (typically 1 to 3 metric tons per bundle).
Rust Protection:
Coated with industrial-grade corrosion-inhibiting oil; optional waterproof plastic wrapping or woven textile wrapping for ocean freight combined with container desiccants.
Loading & Port Logistics:
Loaded into 20GP/40GP containers using wooden dunnage and steel wire rope bracing to prevent shifting during transit. Port proximity to major terminals ensures streamlined loading.
FAQ
Q: What is the difference between hot-rolled and cold-drawn carbon steel square bars?
A: Hot-rolled bars are processed at elevated temperatures, resulting in a scaled surface and standard tolerances, suitable for general structural work. Cold-drawn bars are processed at room temperature through a die, yielding tighter dimensional accuracy, a bright smooth surface finish, and higher yield strength.
Q: Can you provide Material Test Certificates (MTC) prior to shipment?
A: Yes. Every shipment includes an EN 10204 3.1 Mill Test Certificate detailing actual chemical analysis, mechanical property test results, and heat treatment logs mapped to international standards.
Q: What is the standard Minimum Order Quantity (MOQ) for custom sizes or grades?
A: MOQ typically depends on the rolling schedule and grade availability. For standard sizes (e.g., AISI 1045 equivalents, 20mm–80mm), smaller trial orders or mixed container loads are accepted. Custom rolling runs generally require a minimum of 3 to 5 metric tons per size.
Q: How do you prevent rust on square bars during ocean shipping?
A: Bars are coated with a neutral anti-rust oil layer. For overseas container transport, desiccants are placed inside the container to absorb moisture, and waterproof packaging can be applied upon request.
Q: What are the typical straightness tolerances you can guarantee?
A: Standard straightness is controlled within 1.5 mm per meter. For precision machining applications, we can achieve strict straightness tolerances down to 0.75 mm per meter via multi-roll straightening machines.
Q: What payment terms and trade terms do you support?
A: We primarily operate under FOB, CIF, or CFR terms via T/T (Telegraphic Transfer) and irrevocable Letter of Credit (L/C) at sight for established B2B accounts.
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