Description
Mill-Direct Q235 Q345 ERW Welded Steel Pipe Supply — Produced in our own steel mill with full material traceability from billet to finished pipe, eliminating third-party sourcing gaps for structural projects.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 ERW Longitudinal Seam Submerged Arc Welded Steel Pipe |
| Product Type | ERW Welded Steel Pipe / Circular Hollow Section |
| Steel Grade | Q235, Q345 |
| Standard | GB |
| Section Shape | Round |
| Size Range | Outer Diameter 10–2620 mm |
| Wall Thickness | 0.5–80 mm |
| Length | 6 m / 12 m (or custom) |
| Technique | ERW / Longitudinal Seam Submerged Arc Welded / Hot Rolled |
| Surface Treatment | Oiled / Coating / Thread / Groove / Beveled |
| Tolerance | ±1% |
| Ends | Plain / Threaded / Grooved / Beveled |
| Application | Structure Pipe |
| MOQ | 25 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Commercial Construction | Building frames, column systems, roof truss supports |
| Industrial Facilities | Factory structural columns, equipment support platforms, mezzanine frames |
| Infrastructure | Bridge handrails, pipeline support structures, highway sign gantries |
| Energy & Utilities | Solar mounting structures, power transmission tower bracing, substation frames |
| EPC Projects | Process pipe racks, conveyor support systems, modular plant structures |
What Wall-Thickness Tolerance Costs on a Q235 Q345 ERW Welded Steel Pipe Order
Tolerance drift beyond ±1% turns a certified structure pipe into a customs rejection or a site rejection.
Buyers sourcing Q235 Q345 ERW welded steel pipe from overseas suppliers routinely encounter negative tolerance exceeding allowable limits — the pipe arrives lighter than specified, dimensional inspection fails, and the entire batch faces rejection at the project site or during third-party inspection. Material traceability gaps compound the problem: when the fabricator sources raw material from unverified mills, heat number records break down, and mill test certificates become unreliable. [NEED_CITE: structural steel tolerance requirements for circular hollow sections]
Matching Round CHS to Structural Frame and Pipeline Support Applications
The Q235 and Q345 grades in this Q235 Q345 ERW welded steel pipe cover the full spectrum of structural demand — from light-gauge framing in warehouse construction (Q235, thinner wall sections) to heavy-load columns and pipeline supports requiring higher yield capacity (Q345, walls up to 80 mm). The outer diameter range of 10–2620 mm allows a single procurement source to supply everything from small bracing tubes to large-diameter structural columns, reducing the complexity of splitting orders across multiple suppliers. Our vertically integrated production means the same quality system governs both the raw steel and the welding process, so weld integrity on the longitudinal seam matches the base material properties documented in the mill test certificate.
Engineering Compliance and Certification for International Structural Projects
Structural projects in the EU require EN 1090 execution class compliance, while Middle East and Southeast Asian EPC contracts frequently specify AWS D1.1 welding standards. The GB-standard Q235 and Q345 grades in this Q235 Q345 ERW welded steel pipe have established equivalence mappings to S235/S355 (EN) and A36/A572 (ASTM), enabling cross-standard specification acceptance when supported by proper documentation. [NEED_CITE: steel grade equivalence between GB, EN, and ASTM standards] Surface treatment selection — oiled for inland transit protection, coating for corrosive environments, beveled ends for field welding — must align with the project’s environmental exposure category and connection method. Third-party inspection by SGS or BV verifies dimensional accuracy and weld quality before shipment, providing the documentation package that customs authorities and project engineers require. [NEED_CITE: third-party inspection requirements for structural steel imports]
Understanding Q235 and Q345 Grades with ERW Longitudinal Seam Welding
The Q-series steel grade system follows Chinese national standards, where the number indicates minimum yield strength in MPa — Q235 provides adequate strength for general structural framing, while Q345 delivers higher load-bearing capacity for columns, heavy platforms, and seismic-zone construction. The ERW longitudinal seam submerged arc welding process produces a continuous, uniform weld bead along the pipe’s length, offering superior weld penetration and consistency compared to manual welding methods. This process is particularly suited to the wide diameter range (10–2620 mm) and thick-wall capability (up to 80 mm) specified here, as submerged arc welding handles heavy wall sections without the heat input limitations of other methods. The ±1% tolerance on both outer diameter and wall thickness ensures that theoretical weight calculations match actual delivered weight — critical for structural engineering calculations and project cost control. Multiple end treatments (plain, beveled, threaded, grooved) accommodate different field connection requirements: beveled ends for butt welding, threaded ends for mechanical coupling, grooved ends for grooved coupling systems.
Hidden Costs of Procuring Non-Compliant Q235 Q345 ERW Welded Steel Pipe
Pipes with wall thickness below specified tolerance reduce structural load capacity and may fail engineering inspection — the cost of replacing rejected material on-site far exceeds the initial price difference. Missing or forged mill test certificates trigger customs holds and project delays, particularly in markets with strict import documentation requirements. [NEED_CITE: consequences of non-compliant structural steel in international construction projects] When the fabricator cannot provide complete quality documentation — WPS, PQR, dimensional reports, coating thickness records — the project owner faces liability exposure and insurance complications.
Why Structural Steel Buyers Source Q235 Q345 ERW Welded Steel Pipe from Our Mill
Our production starts from our own steel mill, where billet quality and chemical composition are controlled before the pipe is ever formed — this eliminates the material traceability gaps that plague brokers who source raw material from unknown suppliers. The in-house metallurgical laboratory tests every heat for chemical composition and mechanical properties, generating mill test certificates that carry full traceability back to the original heat number. With over 2,800 specifications maintained in inventory, we can consolidate orders across multiple diameters and wall thicknesses into single shipments, reducing freight costs and simplifying customs clearance. Professional loading planning handles the logistics of oversized pipes (up to 2620 mm OD) with proper lashing and weight distribution for ocean container and breakbulk shipment. Complete export documentation — including certificate of origin, packing lists, and third-party inspection reports — is prepared in-house to meet the specific requirements of destination country customs authorities.
Documentation & Compliance
- Mill test certificate documenting Q235 and Q345 chemical composition and mechanical properties per GB standard, with heat number traceability
- SGS or BV third-party inspection report verifying outer diameter, wall thickness, and longitudinal seam weld quality before shipment
- ISO 9001 quality management system certificate covering the integrated steel production and pipe fabrication process
- Complete dimensional inspection report covering OD, WT, length, straightness, and end preparation for each production batch
- Welding procedure specification (WPS) and procedure qualification record (PQR) for the ERW submerged arc welding process
- Export documentation package including packing list, bill of lading, and certificate of origin formatted for destination country customs
Packaging, Loading & Delivery
- Q235 and Q345 ERW pipes bundled with steel strips and edge protectors, with bundle weight optimized for container or breakbulk loading based on pipe diameter and wall thickness
- Oiled surface treatment applied before bundling to prevent corrosion during ocean transit, with additional plastic wrapping available for high-humidity destinations
- Large-diameter pipes (above 1000 mm OD) loaded on flat racks or breakbulk vessels with custom cradles to prevent ovality damage during transport
- Custom cut lengths available within the 6 m to 12 m range, with cut ends deburred and protected to maintain bevel or thread integrity
- Heat number and steel grade stenciled on each pipe for site identification and traceability verification during installation
- FOB, CIF, and DDP shipping terms available, with professional loading supervision to maximize container utilization for mixed-diameter orders
Start Your Q235 Q345 ERW Welded Steel Pipe Inquiry
Submit your project specifications — including outer diameter, wall thickness, length, steel grade, quantity, and destination port — to receive a detailed quotation with production timeline and mill test certificate sample. Our engineering team reviews your drawings and specifications within 24 hours, confirming dimensional feasibility, welding procedure compliance, and surface treatment options for your application. Third-party inspection arrangements and export documentation requirements are confirmed before production begins, ensuring smooth customs clearance at your destination.
Frequently Asked Questions
Q: What is the steel grade equivalence between Q235/Q345 (GB) and international standards like EN or ASTM?
A: Q235 corresponds approximately to S235 (EN 10025) and A36 (ASTM A36), while Q345 aligns with S355 (EN 10025) and A572 Grade 50 (ASTM A572). We provide cross-reference documentation with mill test certificates to support specification compliance for international projects.
Q: Can you arrange third-party inspection before shipment?
A: Yes, we coordinate SGS, BV, or other nominated third-party inspectors to verify dimensional accuracy, weld quality, and surface treatment at our facility before shipment. Inspection reports are included in the export documentation package.
Q: What is the minimum order quantity for custom lengths and end treatments?
A: The standard MOQ is 25 tons. Custom lengths within the 6 m to 12 m range and end treatments (beveled, threaded, grooved) are available within this quantity, with specific requirements confirmed during quotation.
Q: How do you ensure material traceability from steel production to finished pipe?
A: Our vertically integrated mill produces both the raw steel and the finished pipe, with every heat number tracked through chemical composition testing, mechanical property verification, and dimensional inspection. Mill test certificates carry complete traceability from billet to finished product.
Q: What surface treatment options are available for corrosion protection?
A: Standard options include oiled surface for transit protection, external coating for corrosion resistance, and bare (black) finish for projects requiring field-applied coating. Specific coating systems can be applied per project specification.
Request Your Q235 Q345 ERW Welded Steel Pipe Quotation
Send your project drawings, specifications, and quantity requirements to receive pricing with full mill test certificate documentation and production timeline confirmation.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
