Product Overview
Cold Drawn Square Bar is manufactured by cold-drawing hot-rolled wire rods or carbon/alloy steel bars through a tungsten carbide die at room temperature. This cold-working process alters the grain structure to increase tensile strength and delivers precise dimensional accuracy accompanied by a clean, scale-free surface finish.
Our manufacturing setup features continuous acid pickling, multi-stage drawing benches, precision roller straightening units, and inline eddy current testing. By integrating drawing and non-destructive testing into a single continuous workflow, we supply tight-tolerance square bars directly to CNC machining shops and OEMs, eliminating preparatory rough-milling steps.
Technical Specifications & Standards
|
Parameter |
Specification & Range |
|
Size Range |
6mm to 100mm (1/4" to 4") |
|
Dimensional Tolerance |
ISO h11, h12 (Custom tolerances down to +-0.03mm available) |
|
Primary Steel Grades |
AISI/SAE 1018, 1045, 1020, 4140, EN8, EN19, S35J2 |
|
Surface Finish |
Cold drawn, bright, smooth, Ra <= 3.2 um (free of mill scale and oxide pits) |
|
Straightness |
Max 1.0mm per 1000mm length (Processed via multi-roll precision straighteners) |
|
Delivery Condition |
Cold drawn, cold drawn + stress relieved (annealed upon technical request) |
|
Standard Lengths |
3m, 5800mm, 6m, or custom cut-to-length (length tolerance +-2mm) |
|
Material Traceability |
Mill Test Certificate (MTC) per EN 10204 3.1 supplied with every individual heat batch |
Product Advantages for Machining & Engineering
Reduced Cycle Times:
Cold drawing eliminates the size variance inherent in hot-rolled stock, minimizing stock removal allowances during turning, milling, or broaching.
Elevated Mechanical Properties:
Cold work hardening increases yield strength and tensile strength relative to hot-rolled equivalents, improving structural load capacity.
Clean Surface Integrity:
Absence of mill scale prevents premature cutting tool wear on high-speed CNC centers and allows for direct plating or welding in structural applications.
Runout Control:
Multi-roll straightening processes ensure bar straightness, preventing vibration, whip, or imbalance during high-RPM automated feeding.
Typical Industrial Applications
Machine Tool Construction: Guide rails, slides, machine frames, and structural brackets requiring exact square geometry.
Automotive & Agricultural Machinery: Transmission keys, drive shafts, linkage rods, and heavy-duty chassis brackets.
Industrial Hardware & Fasteners: Structural studs, high-strength bolts, heavy nuts, and custom anchoring components.
Fluid Power & Hydraulics: Valve bodies, internal actuator components, and manifold fittings.
Customization, Thermal Treatment & Processing
Alloy & Carbon Grades: Production runs tailored to customer-specified chemical compositions, including free-cutting steels or specialized carbon-manganese grades.
Stress-Relieving Thermal Treatment: In-house protective-atmosphere annealing furnaces eliminate internal residual stresses induced by cold drawing, preventing component warping during subsequent deep-slotting or heavy milling operations.
Precision Saw Cutting: Mechanical band-saw cutting services provide deburred, square ends aligned with automated assembly requirements.
Surface Preservation: Heavy-duty anti-rust oil application and VCI (Volatile Corrosion Inhibitor) packaging configurations designed for maritime shipping protection.
Quality Control & Metallurgical Inspection
Chemical Composition Verification: Spectrometer analysis performed on every raw material heat lot prior to entering the drawing line.
Dimensional Monitoring: Continuous optical and laser micrometer profiling during the drawing pass to instantly detect tolerance drift.
Non-Destructive Testing (NDT): 100% online or offline Eddy Current Testing (ET) executed to screen for surface micro-fissures and internal drawing defects.
Mechanical Validation: Tensile testing and Brinell/Rockwell hardness testing conducted per production lot, mapped directly to the heat number documented on the EN 10204 3.1 MTC.
Export Packaging & Logistics
Bundle Configuration:
Hexagonal bundles secured with high-tensile steel strapping and separated by wooden dunnage to facilitate safe crane and forklift handling.
Moisture Protection:
Lined internally with heavy-duty plastic film and exterior-wrapped in woven packaging material to withstand extended ocean freight transit.
Identification:
Steel identification tags riveted to each bundle, explicitly detailing the steel grade, heat number, exact dimensions, bundle weight, and lot ID.
FAQ
Q: What is the typical Minimum Order Quantity (MOQ) for custom sizes or non-standard steel grades?
A: For standard carbon grades (such as AISI 1018 or 1045) in common sizes, the MOQ starts at 2 metric tons per dimension. For specialized alloy grades or custom non-standard dimensions, the MOQ is 5 metric tons to align with minimum rolling and drawing mill batches.
Q: Do you supply stress-relieved cold drawn square bars to prevent warping during machining?
A: Yes. Cold drawing inherently creates internal residual stresses. For components undergoing heavy keyway cutting, deep slotting, or asymmetric milling, we provide thermal stress-relieved (annealed) bars to ensure dimensional stability and prevent post-machining distortion.
Q: How is bar straightness verified and maintained for long production lengths?
A: Following the drawing stage, bars pass through multi-roll vertical and horizontal precision straightening machinery. Our baseline straightness specification is maintained within 1.0mm per meter, with tighter tolerances available upon technical agreement for automated bar-feed systems.
Q: Can we request third-party inspections (e.g., SGS, Bureau Veritas) prior to shipment?
A: Yes. We regularly accommodate independent third-party inspections at our manufacturing facility at the buyer's request and expense. Every shipment inherently includes our certified EN 10204 3.1 Mill Test Certificate as a standard deliverable.
Q: What is the standard production lead time for new orders?
A: Standard production lead time runs between 25 and 35 days from official order confirmation and deposit receipt, dictated by current rolling schedules and required thermal treatment processes. Ready stock items ship within 7 business days.
Q: What protective measures are taken to prevent oxidation during ocean transit?
A: Bars are coated with a moisture-displacing, heavy-duty rust-preventive oil and encased in VCI-treated protective film or moisture-barrier wrapping inside strapped bundles engineered to endure multi-week maritime conditions.
Request a Technical Quotation
Submit your precise technical parameters below to receive a formal quotation within 24 hours:
• Steel Grade / Standard (e.g., AISI 1018, AISI 1045, 4140)
• Size & Side Length (mm or inches)
• Tolerance Class (e.g., ISO h11, h12)
• Quantity & Length Requirements
• Destination Port (for CIF quotes) or Factory Ex-Works
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