Description
Factory-Direct Rectangular ERW Tubes — Every Q235 rectangular ERW welded steel hollow section tube rolls off our own ERW line in Jinan, shipped with original mill test certificates and no trading markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Rectangular ERW Welded Steel Hollow Section Tube |
| Product Type | Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213-2001, DIN EN 10217-1-2005 |
| Section Shape | Rectangular |
| Size Range | 20×20 mm, 50×25 mm, 60×40 mm, 80×40 mm, 50×50 mm |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Customers’ Request |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Invoicing | By Theoretical Weight |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding supports, curtain wall keels, solar panel mounting structures |
| Machinery & Equipment | Conveyor frames, crane booms, agricultural machinery chassis, equipment guardrails |
| Oil, Gas & Chemical | Low-pressure fluid transport lines, chemical fertilizer distribution pipes, gas supply manifolds |
| Industrial Piping | Boiler feed lines, heat exchanger casings, drill pipe casings |
Where Weld Seam Integrity Decides Whether Your Container Clears Customs
A missing or failed weld seam test report is the single most common reason rectangular hollow sections get held at destination ports.
I have seen entire shipments of ERW rectangular tubes sit in Jebel Ali for weeks because the weld fusion zone failed ultrasonic re-inspection — even though the mill certificates looked clean on paper. Global buyers sourcing Q235 rectangular ERW welded steel hollow section tubes often face quality uncertainty: inconsistent weld penetration, unclear grade traceability, and no independent lab verification before loading. When customs authorities or project supervisors request SGS re-testing at the port, the cost of demurrage, re-inspection, and potential rejection far exceeds the price difference between a reliable supplier and a questionable one. [NEED_CITE: EN 10219 cold-formed welded hollow section weld integrity requirements]
Matching Q235 ERW Rectangular Tubes to Structural and Fluid Applications
Q235 rectangular ERW welded steel hollow section tubes in sizes from 20×20 mm to 80×40 mm cover the most frequently requested dimensions for building frames, machinery structures, and low-pressure fluid lines. The ERW process produces a continuous longitudinal weld with tight dimensional control at ±1% tolerance, making these tubes suitable for projects requiring precise fit-up during welding and punching. Hot rolled surface with slight oiling provides baseline corrosion protection during ocean transit without adding cost — a practical choice for indoor structural applications or projects where final painting or galvanizing will be applied on site.
Engineering Compliance and Certification Requirements for ERW Hollow Sections
Structural applications in the EU require compliance with EN 10219 for cold-formed welded structural hollow sections, while North American projects typically reference ASTM A500 or A53. Q235 grade roughly corresponds to S235JR in the EN system and ASTM A283 Grade C in the US framework, though exact equivalence depends on chemical composition and mechanical testing results documented in the mill test certificate. [NEED_CITE: steel grade equivalence between Chinese Q-series and EN/ASTM standards] For projects requiring CE marking, the production facility must hold FPC certification under EN 10210/EN 10219, and each heat number must be traceable to original mill test records. Custom cut-to-length service eliminates secondary cutting waste at the job site, while in-house welding and punching capabilities allow pre-fabrication before shipment — reducing labor costs in high-wage destination markets.
Understanding Q-Series Steel Grades and ERW Welding Characteristics
The Q-series designation (Q195, Q215, Q235, Q345) follows the Chinese GB/T 700 standard, where the number after “Q” indicates minimum yield strength in MPa. Q235 remains the most widely specified grade for general structural and fluid transport applications due to its balance of formability, weldability, and cost. ERW welding uses high-frequency electric current to fuse the edges of hot-rolled coil without filler material, producing a clean longitudinal seam with minimal heat-affected zone — ideal for rectangular and square hollow sections where consistent corner geometry matters for connection fit-up. [NEED_CITE: ERW welding process characteristics for structural hollow sections] The slight oiling applied after hot rolling prevents flash rust during storage and transit but does not constitute a corrosion protection coating — buyers requiring long-term outdoor exposure should specify galvanized or painted finish separately.
Hidden Costs of Procuring Rectangular ERW Tubes Without Verified Documentation
Purchasing Q235 rectangular ERW welded steel hollow section tubes based on price alone — without verified mill test certificates, third-party inspection reports, or clear heat number traceability — exposes buyers to material substitution risks, customs clearance delays, and potential structural safety failures during project inspection. [NEED_CITE: consequences of missing mill test certificates in steel import compliance] A shipment rejected at destination port due to failed weld seam testing or grade mismatch can incur demurrage charges exceeding the original product value, while re-procurement delays cascade through project timelines. The cost of SGS or BV pre-shipment inspection is marginal compared to these risks, yet many suppliers omit this option or provide forged certificates that fail verification.
Why Engineering Buyers Source Q235 Rectangular ERW Tubes from Shandong Xin Jiyuan
Our Jinan facility operates three dedicated ERW production lines with monthly capacity exceeding 20,000 tons, covering over 2,800 specifications in rectangular, square, and round hollow sections — enabling single-source procurement for multi-category project orders. Every batch of Q235 rectangular ERW welded steel hollow section tube ships with original mill test certificates documenting chemical composition and mechanical properties per heat number, with optional SGS/BV third-party inspection available before loading. Our in-house理化 laboratory conducts three-stage quality control covering dimensional tolerance, weld seam ultrasonic testing, and mechanical property verification. Factory-direct pricing eliminates trading company markups, while volume discount programs reward long-term procurement partnerships. Professional export documentation handling ensures CE certificates, packing lists, and bills of lading meet destination country customs requirements — reducing clearance delays.
Documentation & Compliance
- Mill test certificate documenting Q235 chemical composition (C, Mn, Si, S, P) and yield strength per GB/T 700 standard, traceable by heat number
- CE certificate confirming compliance with EN 10219 for cold-formed welded structural hollow sections, required for EU market entry
- ISO 9001:2015 quality management system certificate covering production processes and inspection procedures
- SGS or BV third-party inspection report verifying dimensional tolerance, weld seam quality, and surface condition before container loading
- Material traceability sheet linking each bundle to heat number, production date, and mill test certificate reference
- Complete customs documentation package including commercial invoice, packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235 rectangular tubes bundled with steel strips and edge protectors to prevent surface damage to the hot rolled oiled finish during ocean transit
- Slight oiling applied to all surfaces provides short-term rust prevention; bundles wrapped in waterproof paper for container shipping
- Container loading optimized for rectangular section geometry — 20ft containers accommodate 50×25 mm and 60×40 mm tubes nested efficiently, maximizing weight utilization
- Custom cut-to-length service available per order specifications, eliminating on-site cutting waste and reducing labor costs at destination
- Each bundle tagged with heat number, steel grade (Q235), section size, and theoretical weight for site identification and traceability
- FOB, CIF, and DDP shipping terms available; professional logistics coordination handles customs clearance and port documentation
Requesting Quotations and Mill Test Certificates for Your Project
Submit your required section sizes, steel grade (Q195–Q345), total tonnage, and destination port to receive competitive bulk pricing with volume discounts and typical production lead times. We provide original mill test certificates and arrange SGS/BV third-party inspection upon request — critical for projects requiring verified material compliance. Non-standard dimensions and custom processing services (cutting, punching, bending) are available for orders meeting minimum quantity requirements.
Frequently Asked Questions
Q: What is the difference between Q235 and S235JR steel grades?
A: Q235 is the Chinese GB/T 700 designation, while S235JR follows the European EN 10025 standard. Both specify minimum yield strength of 235 MPa, but chemical composition limits and impact testing requirements differ slightly. Mill test certificates confirm actual composition and mechanical properties for each heat.
Q: Can you provide third-party inspection before shipment?
A: Yes, SGS and BV third-party inspection services are available upon request. Inspection covers dimensional tolerance verification, weld seam quality testing, surface condition assessment, and witness of mechanical testing. Inspection reports are issued independently by the third-party agency.
Q: What is the minimum order quantity for custom sizes?
A: Standard sizes (20×20 mm to 80×40 mm) are available from ready stock with 5-ton minimum order. Non-standard dimensions or custom lengths require production scheduling, with typical minimum orders of 5–10 tons depending on specification.
Q: How are Q235 rectangular tubes invoiced?
A: Invoicing is based on theoretical weight calculated from section dimensions, wall thickness, and length per standard steel density. Actual weight may vary within ±1% dimensional tolerance. Packing lists document bundle count, piece quantity, and total theoretical weight for each shipment.
Q: Do you provide CE certification for European projects?
A: Yes, our production holds CE certification under EN 10210 and EN 10219 for structural hollow sections. CE certificates and Factory Production Control documentation are provided with each shipment destined for EU markets.
Get Your Q235 Rectangular ERW Tube Quote with Mill Test Certificates
Send your specifications, quantity, and destination to receive bulk pricing and compliance documentation within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
