Q235 Cold Drawn Round Bar, Carbon Steel Supplier
GB-standard Q235 cold drawn round bar in Φ5–Φ100 mm — bright surface, tight tolerance, easy welding, factory-direct with full material traceability.
Q235 is the most widely used carbon structural steel in China, and in its cold drawn form it combines the economy of a general-purpose grade with the precision benefits of cold drawing: a bright, oxide-free surface, tighter dimensional tolerance and better straightness than hot rolled bar. This makes Q235 cold drawn round bar a practical choice for buyers who need consistent machining and welding performance without paying for alloy grades.
Our Q235 cold drawn round bar is produced by Suzhou Zhenfu Cold-Drawn Steel Co., Ltd., a factory-direct manufacturer with over 18 years of experience, an annual capacity of 150,000 tons and CE certification. Every batch is traceable to the original steel mill heat number, and bilingual mill test certificates are provided with delivery.
We also supply cold drawn square steel, flat steel and hexagonal steel in Q235/S235JR grade.
Product Properties
After cold drawing, Q235 round bar delivers a combination of properties that suit both machining and structural use:
High dimensional accuracy — tight tolerance reduces machining allowance and scrap in automatic production
Bright, smooth surface — no descaling before machining, plating or direct assembly
Increased yield and tensile strength — cold working work-hardens the surface layer
Excellent weldability — low-carbon composition allows easy welding and bending
Cost effectiveness — general-purpose grade at a stable price for high-volume orders
Available Grades, Equivalents and Sizes
In addition to Q235, the same cold drawn round bar line is available in a range of carbon, alloy and free-cutting grades, with equivalents across common international standards:
| GB Grade | EN Equivalent | JIS Equivalent | ASTM Equivalent | Southeast Asia / Middle East |
|---|---|---|---|---|
| Q235 (A3) | S235JR (1.0038) | SS400 | A36 / 1018 | S235JR / SS400 / A36 |
| 20# | C22 (1.0402) | S20C | 1020 | C22 / S20C / 1020 |
| 45# | C45 (1.0503) | S45C | 1045 | C45 / S45C / 1045 |
| 40Cr | 41Cr4 (1.7035) | SCr440 | 5140 | 41Cr4 / SCr440 / 5140 |
| 42CrMo | 42CrMo4 (1.7225) | SCM435 | 4140 | 42CrMo4 / SCM435 / 4140 |
| 12L14 | 11SMnPb30 (1.0718) | SUM24L | 12L14 | 11SMnPb30 / SUM24L |
| 12L15 | 11SMn37 (1.0736) | SUM31L | 12L15 | 11SMn37 / SUM31L |
| Q355D | S355JR (1.0045) | SM490A | A572 Gr 50 | S355JR / SM490A |
| 65Mn | — | — | — | — |
Available production sizes: Φ5–Φ100 mm for all grades above; custom intermediate diameters and lengths on request.
Why Choose Q235 Cold Drawn Round Bar?
Q235 is the most commonly used carbon structural steel in China, and its cold drawn form offers a unique balance of properties that make it the default choice for a wide range of general engineering applications.
Excellent weldability: With carbon content below 0.25%, Q235 can be welded using all common methods (MIG, TIG, arc welding) without preheating or post-heating, making it ideal for structural fabrication and welded assemblies.
Good formability: Q235 cold drawn round bar can be bent, forged, and machined without cracking, giving manufacturers flexibility during production.
Cost-effective: As a general-purpose grade, Q235 is available in stable supply at competitive prices, making it suitable for high-volume orders where alloy steel grades would be unnecessarily expensive.
Internationally recognized: Q235 has direct equivalents in major international standards — S235JR in EN, SS400 in JIS, and A36 in ASTM — so it is easy for global buyers to specify and approve.
Selection Guide
| Grade | Key Advantages | Main Applications |
|---|---|---|
| Q235 | Smooth surface, high dimensional accuracy, easy welding and bending, cost-effective | Equipment brackets, hardware fittings, general structural shafts |
| 20# | Low carbon, high toughness, good plasticity, excellent cold working and welding | Pin shafts, chains, automotive and agricultural machinery stamping parts |
| 45# | Balanced strength and hardness, wear-resistant, quenchable and temperable (HRC 19–25 as annealed) | Main shafts, drive shafts, bolts, general machined parts |
| 40Cr | Good hardenability, fatigue-resistant, high strength, minimal distortion after heat treatment | Gears, crankshafts, construction machinery wear-resistant parts |
| 42CrMo | High toughness, impact-resistant, good high-temperature performance, stable mechanical properties | Wind power, hydraulics, automotive half-shafts, heavy machinery |
| 12L14 | Free-cutting, high machining efficiency, precise tolerance, smooth surface | CNC precision shafts, instruments, automation equipment components |
| 12L15 | Lead-free and eco-friendly, export-compliant, high dimensional consistency | EU / US / JP eco-friendly orders, electronics, medical precision components |
| Q355D | Good low-temperature toughness, high strength, weather-resistant, strong load-bearing capacity | Mining, bridges, construction machinery, low-temperature equipment structures |
| 65Mn | High elasticity and fatigue resistance after proper heat treatment | Bicycle brake springs, spring steel parts, shock-absorbing components |
Bicycle brake spring application: 65Mn spring steel round bar is our specialized product for bicycle brake springs, engineered to withstand frequent mechanical loads, temperature swings and harsh riding environments. Q235 remains the economical choice for brake frames and auxiliary fittings on the same product line. Read more: cold drawn round steel overview.
| Item | Specification |
|---|---|
| Product | Q235 / S235JR Cold Drawn Round Steel Bar |
| Diameter Range | Ø5 mm – Ø80 mm |
| Length | 2,000 – 6,000 mm (cut-to-size available) |
| Tolerance | h9 / h11 per EN 10278 |
| Surface Finish | Bright drawn (WD) / Peeled (WP) |
| Carbon Content | 0.14% – 0.22% |
| Yield Strength | ≥ 235 MPa |
| Tensile Strength | 370 – 500 MPa |
| Elongation | ≥ 26% |
| Welding | Excellent (all conventional methods) |
| Certification | CE, ISO 9001, Mill Test Certificate (EN 10204 3.1) |
Typical Applications of Q235 Cold Drawn Round Bar
Q235 cold drawn round bar is commonly used in applications where dimensional accuracy and surface finish matter more than high strength:
Equipment brackets and supports
Hardware fittings and fasteners
General structural shafts and pins
Automotive stamping parts
Agricultural machinery components
Construction fittings and connectors
Machine tool bases and frames
General machined parts requiring tight tolerance
Quality Assurance & Traceability
Every batch of Q235 cold drawn round bar supplied by Suzhou Zhenfu comes with full material traceability:
Mill Test Certificate (MTC): EN 10204 3.1 certificate showing chemical composition and mechanical properties
Heat number marking: Each bundle is stamped with the original heat number from the steel mill
Dimensional inspection: Diameter, straightness, and length are checked before shipment
Surface inspection: Bars are visually inspected for cracks, laps, and surface defects
We purchase Q235 raw material directly from major Chinese steel mills such as Baowu, Shagang, and Ansteel, ensuring consistent chemical composition and mechanical properties across every production batch.
Quality and Documentation
Material is sourced from leading domestic steel mills (Baowu, Shagang, Ansteel and others) with heat numbers and original mill certificates. Four-stage quality control covers incoming material inspection, hourly production patrol, semi-finished sampling and 100% final inspection. Certifications: ISO quality management system and CE. Bilingual MTCs and third-party inspection by SGS or BV are available on request.
Ordering Information
To request a quotation for Q235 cold drawn round bar, please provide:
Diameter (e.g., Ø20 mm, Ø50 mm)
Required length (standard 6m or cut-to-size)
Tolerance class (h9, h11, or per your drawing)
Quantity (tons or pieces)
Surface finish (bright drawn, peeled, or ground)
Required documentation (MTC 3.1, etc.)
Standard sizes in stock can be shipped within 7 days. Custom diameters and cut-to-size orders typically take 15–25 days. Contact us with your requirements for a detailed quotation.
FAQ
What is the difference between Q235 and 45# cold drawn round bar?
Q235 is a low-carbon structural grade with excellent weldability and low cost, ideal for brackets, frames and light structural parts. 45# has higher strength and hardness and suits shafts, bolts and parts requiring moderate wear resistance. Choose by load and processing requirements.
Can you supply Q235 round bar in non-standard diameters?
Yes. Within our drawing capability we produce custom intermediate diameters and special tolerances on a production basis. Send your requirement and we will confirm feasibility and lead time.
What surface finish do you provide?
The standard cold drawn surface is bright and oxide-free, allowing direct machining, plating or assembly. Custom finishes such as polished or ground surfaces are available on request.
Do you provide material certificates for export?
Yes. Bilingual MTCs with chemical composition and mechanical properties are provided with every batch, traceable to the original steel mill heat number. Third-party inspection by SGS or BV can be arranged.
What is the MOQ and delivery time?
We accept sample orders, small trial orders and LCL consolidation. Stock sizes ship within 3–7 days; production orders follow a fixed schedule with guaranteed ocean shipping dates.
Send your diameter, grade, length and quantity — we will confirm material availability, price and delivery within 24 hours.
