01. Product Overview

Our Steel Round Bar is manufactured from premium-grade billet using advanced hot rolling, cold drawing, and forging processes. Available in a comprehensive range of carbon steel, alloy steel, and bearing steel grades, our round bars deliver the strength, machinability, and surface quality demanded by precision machining, heavy machinery, and structural engineering applications.

From cost-effective Q235B/A36 general structural steel to high-wear 40Cr/4140 alloy steel and ultra-high-strength 42CrMo forged bar, we provide the exact grade, diameter, tolerance, and surface finish your project requires. Every bar is produced under rigorous ISO-certified quality systems with full material traceability.

02. Key Features & Advantages

l Multiple Manufacturing Processes

Ø Feature: Hot Rolled, Cold Drawn, Forged, and Peeled/Turned bars available.

Ø Advantage: Each process optimized for specific requirements — tight tolerances (cold drawn h9-h11), high density (forged), or cost efficiency (hot rolled).

Ø Benefit: "One Supplier, All Bars." No need to source from multiple mills — we deliver the exact bar type your application demands.

l Extensive Grade Coverage

Ø Feature: Carbon structural (Q235, A36, 20#), quality carbon (45#, 1045), alloy structural (40Cr, 42CrMo, 4140, 4340), and bearing steel (GCr15, 52100).

Ø Advantage: From general fabrication to high-stress rotating shafts and bearing rings — one grade per application.

Ø Benefit: "Right Steel, Right Performance." Eliminates over-spec cost waste and under-spec failure risk.

l Precision Tolerances & Surface Finish

Ø Feature: Cold drawn bars achieve h9-h11 tolerance; Turned/Ground/Polished (TG&P) achieves h6-h8 with Ra ≤0.8μm.

Ø Advantage: Ready for direct CNC loading without pre-machining — saves turning time and tool wear.

Ø Benefit: "Plug and Machine." Reduces per-part processing cost by 15-30% compared to raw hot rolled stock.

l Full Traceability & Certified Quality

Ø Feature: Every heat/lot comes with a Mill Test Certificate (MTC/EN 10204 3.1) showing chemical composition and mechanical properties.

Ø Advantage: Full compliance with international standards (ASTM, AISI, JIS, DIN, EN, GB) — auditable at any time.

Ø Benefit: "Audit-Ready Supply Chain. Meets the strictest procurement requirements of oil & gas, automotive, and heavy machinery OEMs.

03. Technical Specifications

04. Versatile Applications

l Precision Machining & Automotive

Hot-rolled 45# / 1045 and alloy 40Cr / 4140 round bars are the backbone of CNC-machined shafts, gears, bolts, pins, and hydraulic cylinder rods. Cold drawn bright bars go straight into Swiss-type lathes with zero pre-turn.

l Construction & Structural Engineering

Q235B / A36 round bars in large diameters (50-300mm) are widely used for reinforcement, anchor bolts, structural columns, and bridge components. High weldability and consistent yield strength ensure code compliance.

l Oil & Gas / Heavy Machinery

42CrMo / 4140 quenched & tempered bars are the industry standard for drill collars, pump shafts, heavy-duty gears, and high-pressure flanges. Forged round bars with superior internal soundness are mandatory for critical rotating parts.

l Power Generation & Bearing

GCr15 / 52100 bearing steel round bars are precision-ground to produce ball bearing rings, roller bearings, and high-speed spindle components requiring exceptional wear resistance and fatigue life.

05. Why Choose Us?

1.Multi-Mill Supply Network : Strategic partnerships with top-tier Chinese steel mills ensure competitive pricing and consistent availability across all grades.

2. ISO-Certified Quality System: ISO 9001 compliant production with in-house spectrometry and mechanical testing labs — every heat verified before shipment.

3. Value-Added Processing: In-house cold drawing, straightening, peeling, saw cutting, and chamfering — we ship bars ready for your production line.

4. Export Expertise: Dedicated export documentation team handles certificates of origin, Form E/Form F, and the 2026 steel export license — no customs delays.

5. Fast Turnaround: Standard grades in stock —7-14 days from order to shipment via Tianjin / Qingdao / Shanghai ports.

06. Packaging & Logistics

l Lead Time: 7-14 days for stock grades and standard sizes; custom production requires scheduling; please consult customer service for details.

l Loading Port: Tianjin / Qingdao / Shanghai.

l Payment Terms : 30% T/T deposit + 70% against BL copy; or 100% Irrevocable L/C at sight.

l Packaging : Bundles of 2-3 tons, marine packaging specifically designed for round steel bars + steel strapping.

l Incoterms: EXW / CFA / FOB / CFR / CIF / DAP/ DDP (negotiable).

l Export Compliance: All shipments include MTC (EN 10204 3.1), packing list, commercial invoice, and export license where required under 2026 regulations.

07. FAQ

Q1: What are the differences between Hot Rolled, Cold Drawn, and Forged round bars? Which one should I choose?

Lowest cost → Hot Rolled

Precision & surface finish → Cold Drawn

Large critical load-bearing parts → Forged

Q2: What international standards do your round bars comply with? Can you provide third-party inspection?

Carbon Steel: ASTM A36 / A108, JIS G4051 (S45C), DIN EN 10060 (C45), GB/T 699 / GB/T 700

Alloy Steel: ASTM A322 / A29 (4140/4340), GB/T 3077 (40Cr/42CrMo)

Bearing Steel: ASTM A295 (52100), GB/T 18254 (GCr15)

Each shipment includes EN 10204 3.1 MTC. Customers may appoint third-party inspectors (SGS/BV/TÜV/Intertek) for pre-shipment inspection (PSI) or independent chemical analysis at buyer's cost.

Q3: What is the difference between 45# (1045) and 40Cr (5140)? When should I upgrade to alloy steel?

45# (1045): Quality carbon steel. Achieves HRC 22-34 after quenching & tempering. Good overall mechanical properties and weldability. Suitable for medium-strength shafts, gears, and connecting rods at lower cost.

40Cr (5140): Alloy structural steel (Cr ~0.9-1.2%). Achieves HRC 28-38 after Q&T with significantly better hardenability than 1045. Ideal for transmission shafts and steering knuckles under alternating loads and moderate impact.

Rule of thumb: when 1045 fails to through-harden (insufficient core hardness) → upgrade to 40Cr.

Q4: Are 42CrMo and 4140 the same? Are they interchangeable?

42CrMo (GB) and 4140 (ASTM/AISI) are closely corresponding grades with highly similar chemical composition — both medium-carbon Cr-Mo alloy steels.

Key difference: Both require Mo 0.15-0.25%, with slight variations in S/P limits.

Interchangeable for most applications, but note: if the customer drawing specifies ASTM 4140 with a strict heat treatment window, stick to 4140. We supply both grades with accurate MTC labeling.

Q5: What is your tightest tolerance? How do you guarantee roundness and straightness?

Cold Drawn Bright Bars: Standard h9-h11 tolerance (e.g., φ20mm = 0/-0.052mm).

TG&P (Turned, Ground & Polished): Achieves h6-h8 tolerance (e.g., φ20mm = 0/-0.013mm), roundness ≤0.01mm, straightness ≤0.2mm/m.

Every batch undergoes 3-point diameter inspection + straightness surface-plate check before shipment. Eddy current testing for surface crack detection is available for premium orders.

Q6: Can you do cut-to-length sawing? What is the length tolerance?

Fully supported. Standard stock is 6m/12m; we can cut to 2m, 3m, 4m, or any specified length.

Sawing tolerance: ±2mm (circular saw / band saw). Clean, burr-free cut face — ready for direct machine loading.

Both-end chamfering and end-face milling are available to eliminate downstream operations.

Note: Cut-to-length involves minor material loss (kerf ~2-3mm), factored into quotation.

Q7: What is your Minimum Order Quantity (MOQ)?

Standard carbon steel (Q235/45#/40Cr φ16-100mm): MOQ 28 MT per spec.

Custom alloy steel (42CrMo/GCr15): MOQ 100 MT per spec.

Large-diameter forged bars (≥200mm): Depending on the specific model, priced by weight.

Q8: How many tons of round bar fit in a 20ft container? How do you calculate freight?

20GP container: Approximately 25-28 MT(varies slightly by diameter mix). 6m lengths fit directly inside the container.

40GP/40HQ container: Approximately 26-28 MT (limited by container weight rating of 28 MT, not by volume).

12m lengths → requires 40ft Flat Rack container or break-bulk vessel.

Freight is calculated based on actual weight and container type. Quotations support EXW / CFA / FOB / CFR / CIF / DAP/ DDP terms. Our partnered forwarders cover major routes to the Middle East, Southeast Asia, Africa, South America, and Europe.

For inquiries, custom specifications, or a quotation, please contact our sales team.

Q9: Does round bar export require a license starting 2026? Can you assist with the application?

Per MOFCOM/GAC Joint Announcement No. 79 (2025), certain steel products have been subject to export licensing since January 1, 2026. Some HS codes under Chapters 7214 and 7228 covering round bars require an export license.

We hold standardized export qualifications with a dedicated documentation team handling export license applications, certificates of origin (CO/Form E/Form F), inspection certificates, and all customs formalities — ensuring smooth clearance.

We recommend providing the accurate HS code when placing an order (or we can assist in confirming it) so license requirements can be verified in advance.