Cold Drawn Pure Iron Bar – Tight Tolerance
High Precision, Superior Surface Finish for Electromagnetic & Precision Components
Direct China manufacturer of cold-drawn pure iron bars with tight tolerance (±0.02mm–±0.05mm). Made from ≥99.9% high-purity electrolytic iron through precision cold drawing and stress-relief annealing. Features high magnetic permeability, low coercivity and stable mechanical properties. Perfect for solenoid plungers, relay armatures, magnetic sensors and precision shafts. Custom diameters 2mm–50mm, factory-direct pricing, ready for high-volume production.
Product Overview
Cold drawn pure iron bars are the preferred choice for applications requiring tight dimensional accuracy, smooth surface finish, and stable soft magnetic performance. Unlike hot rolled or cast products, our cold drawn bars undergo a precision drawing process that:
Achieves tight tolerances (h6, h7, h8, or custom)
Provides excellent surface finish (Ra ≤ 0.8 µm)
Eliminates decarburization and scale
Enhances mechanical strength while maintaining magnetic softness
As the actual manufacturer, we control the entire process from electrolytic iron melting to cold drawing, annealing, and cutting to length. You benefit from factory‑direct pricing, full traceability, and the ability to customize diameter, length, straightness, and magnetic properties (DT4 / DT4C grades).
Key Features
| Feature | Benefit |
|---|---|
| Cold drawn process | Tight tolerance (±0.02‑0.05mm), smooth surface, no scale |
| High purity (≥99.9%) | Low carbon (≤0.003%), low oxygen (≤0.005%) – stable magnetic properties |
| Tight tolerance | Available to h6, h7, h8, or custom ±0.02mm |
| Excellent magnetic performance | High permeability (μ ≥ 10,000), low coercivity (Hc ≤ 48‑72 A/m) |
| Stress‑relief annealed | Removes drawing stresses, restores soft magnetic behavior |
| Cut to length | Any length from 5 mm to 3,000 mm |
| Factory direct | Competitive pricing, short lead times, direct technical support |
Choose Our Cold Drawn Pure Iron Bar?
✅ Tight Tolerance – Ready for Assembly
Our cold drawing process ensures consistent diameter and straightness. Typical tolerances:
| Diameter (mm) | Tolerance Grade |
|---|---|
| 2 – 10 mm | ±0.02 mm |
| 10 – 30 mm | ±0.03 mm |
| 30 – 50 mm | ±0.05 mm |
No secondary grinding needed – saves you time and cost.
✅ Superior Magnetic Performance
Our bars are made from DT4 / DT4C grade electrolytic iron. After cold drawing and annealing, they deliver:
| Grade | Coercivity Hc (A/m) | Permeability μ |
|---|---|---|
| DT4 (standard) | ≤72 | ≥8,000 |
| DT4C (high performance) | ≤48 | ≥10,000 |
Ideal for components requiring fast magnetic response and low residual magnetism.
Custom Diameters & Lengths
We offer:
Diameters: 2 mm to 50 mm (larger sizes available on request)
Lengths: 5 mm to 3,000 mm (cut to exact length)
Shapes: round, square (on request)
Factory Direct – Real Savings
We provide:
Direct pricing from our cold drawing line
Short lead times: 7‑10 days for standard sizes
Free samples for testing (1‑2 pieces, shipping cost only)
Packaging & Delivery
Standard packaging: Bundled with plastic caps on both ends, wrapped in VCI paper, packed in wooden crates or steel‑strapped bundles
Custom packaging: Individual polybag + foam protection for high‑value precision bars
Lead time: 7‑10 days for standard diameters (3‑25 mm); 15‑20 days for larger or custom sizes
Shipping: Sea freight, air freight, or express courier
Factory location: Hebei Province, China – direct loading, quality audit welcome.
Frequently Asked Questions
Q: What is the difference between cold drawn and hot rolled pure iron bar?
A: Cold drawn bars offer tighter tolerances (±0.02‑0.05mm vs. ±0.5‑1.0mm), better surface finish (no scale), and higher strength. However, they require stress‑relief annealing to restore soft magnetic properties. Hot rolled bars are cheaper but less precise and have scale on the surface.
Q: Do you provide stress‑relief annealing?
A: Yes. All our cold drawn bars are stress‑relief annealed after drawing to remove residual stresses and restore magnetic permeability. We can also supply as‑drawn (unannealed) if you prefer to perform annealing yourself.
Q: Can you achieve tolerance tighter than ±0.02mm?
A:For diameters under 10 mm, we can achieve ±0.01 mm (h6 grade) upon request. Additional cost and longer lead time may apply.
Q: Do you offer cut‑to‑length services?
A: Yes. We can cut bars to any length from 5 mm to 3,000 mm with ±0.5 mm length tolerance. For high‑volume orders, we can also chamfer ends or add threaded holes.
Q: What is your MOQ for cold drawn pure iron bars?
A: MOQ is 500 kg per diameter. Sample orders (10‑20 pieces) are available for evaluation – please contact us with your exact size and quantity.
Contact Us
Request factory‑direct pricing for cold drawn pure iron bar – tight tolerance, high purity, and excellent magnetic performance for solenoids, relays, and precision components.
Your trusted Chinese manufacturer of precision soft magnetic iron products.
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