Description
Factory-direct ERW welded round steel pipe supply — Own steel mill produces Q235 and Q345 grades with full heat-number traceability from raw slab to finished pipe.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 ERW Welded Round Steel Pipe |
| Product Type | ERW Welded Round Steel Pipe |
| Steel Grade | Q195, Q215, Q235, Q345, 10#, 20#, S235JR, S275JR, S355JR |
| Standard | GB, API |
| Section Shape | Round / Square / Rectangle |
| Size Range | Outer Diameter 20–200 mm |
| Length | 6 m / 12 m |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Oiled / Non-oiled |
| Tolerance | ±1% |
| Ends | Plain / Beveled (per order) |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Hydraulic Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe |
| MOQ | 15 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Steel frame columns, beam supports, truss bracing, stairway handrails |
| Industrial Plants | Gas distribution lines, hydraulic circuits, chemical fertilizer feed pipes |
| Oil & Energy | Drill pipe casings, oil transport headers, boiler feed lines |
| EPC Projects | Prefabricated pipe racks, structural pipe assemblies, platform supports |
What Negative Tolerance Really Costs on a Fluid Transport Order
A ±1% wall-thickness deviation on a 20 mm OD ERW welded round steel pipe can mean the difference between passing hydrostatic test and failing site inspection.
Overseas buyers sourcing ERW pipes from fragmented suppliers face a recurring problem: the mill test certificate says Q235, but the third-party inspector finds wall thickness drifting below minimum at the weld seam. The pipe was invoiced by theoretical weight, so the buyer paid for steel that was never delivered. Rework means cutting out sections, re-welding, and re-testing — delays that cascade through an entire project schedule. [NEED_CITE: ERW welded pipe dimensional tolerance requirements per GB/T 13793]
How ERW Welded Round Steel Pipe Matches Structural and Fluid Applications
The 20–200 mm outer diameter range covers most structural framing members and small-bore fluid lines in a single procurement package. Q235 and Q345 grades provide the yield strength baseline for load-bearing columns and beam connections, while S235JR through S355JR options allow direct compliance with European structural codes without cross-referencing equivalence tables. Our own steel mill produces the raw material, so every ERW welded round steel pipe carries a heat number that traces back to the original ladle analysis — no gaps in the material certification chain.
Engineering Compliance and Surface Selection for Project Environments
Structural applications require dimensional consistency that meets fabrication tolerances for welding and bolting connections. The ±1% tolerance on our ERW welded round steel pipe ensures that shop drawings translate accurately to physical components without on-site reaming or grinding. For corrosive environments such as chemical fertilizer plants or coastal infrastructure, the oiled surface treatment provides short-term transit protection, while hot-rolled finish accepts field-applied coatings without additional surface preparation. International projects targeting EU markets should specify S235JR or S355JR grades to align with EN 10219 hollow section requirements and avoid customs documentation disputes. [NEED_CITE: EN 10219 cold-formed welded structural hollow sections compliance]
Steel Grade Selection and ERW Process Fundamentals
The Q-series carbon steel grades (Q195 through Q345) follow the Chinese GB standard system where the number indicates minimum yield strength in MPa. Q235 serves general structural and fluid transport applications, while Q345 offers higher strength for load-critical members in bridges and industrial platforms. The S-series equivalents (S235JR, S275JR, S355JR) follow European EN standards with impact toughness requirements at specified test temperatures — critical for projects in cold climates or dynamic loading conditions.
ERW (Electric Resistance Welded) welding forms the longitudinal seam by passing high-frequency current through the steel strip edges, creating a forge weld without filler metal. This process produces a clean, narrow weld seam with mechanical properties approaching the base metal — suitable for structural applications and moderate-pressure fluid transport. Compared to seamless pipe, ERW offers tighter dimensional tolerance and lower cost for the 20–200 mm diameter range. Compared to SSAW (spiral welded), ERW provides straight-seam geometry preferred for architectural exposure and precision fabrication.
The hot-rolled surface condition retains mill scale that must be removed before painting or galvanizing, while oiled surfaces receive a light protective coating to prevent transit corrosion without affecting downstream welding or coating adhesion. Non-oiled finish is specified when the pipe will undergo immediate galvanizing or when the buyer prefers to apply custom surface treatment.
Hidden Costs of Procuring ERW Pipe Without Verified Traceability
Material certification gaps create three categories of project risk. First, pipes sourced from trading companies rather than integrated mills often carry MTCs that cannot be verified against heat numbers — a red flag for inspectors on EU-funded infrastructure projects requiring full traceability. Second, negative tolerance abuse (wall thickness consistently at the low end of ±1%) reduces pressure rating and structural load capacity, even though the pipe passes visual inspection. Third, steel grade substitution — shipping Q235 when Q345 was specified — may not surface until welding procedures fail qualification tests or structural members deflect under design loads. [NEED_CITE: material traceability requirements for structural steel in EN 1090 execution classes]
Why Project Teams Source ERW Welded Round Steel Pipe From an Integrated Mill
Our vertically integrated operation eliminates the material sourcing gap that creates certification risk. The same facility that rolls the steel strip also welds and finishes the pipe, so every ERW welded round steel pipe carries a mill test certificate issued by our own laboratory — chemical composition, tensile properties, and dimensional inspection all documented under one accountability point. The 2,800+ specification range in our raw material inventory means that Q235, Q345, and S-series grades are stocked in multiple diameter and wall thickness combinations, reducing lead time for urgent project schedules.
For fabrication-intensive projects, our in-house processing capabilities (CNC cutting, punching, welding per qualified WPS) allow delivery of pre-processed pipe components rather than raw lengths — reducing site labor and welding qualification burden. Third-party inspection through SGS or BV is available upon request, with full access to production records and dimensional test reports. Professional export packing and container loading planning ensure that 6 m and 12 m lengths are secured against transit damage, with surface treatment preserved through ocean shipment.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition and yield strength per GB standard, with heat number traceability to original ladle analysis
- API certification for oil and gas application pipes, confirming compliance with API 5L or API 5CT requirements as specified
- ISO 9001 quality management certificate covering the integrated steel production and pipe fabrication process
- SGS or BV third-party inspection report available upon request, covering dimensional verification, weld seam quality, and surface treatment condition
- Material traceability report linking each pipe bundle to heat number, production date, and test results
- Export documentation package including packing list, bill of lading, and certificate of origin for customs clearance in destination country
Packaging, Loading & Delivery
- Q235 and Q345 ERW welded round steel pipes bundled with steel strips in seaworthy packaging, with edge protectors to prevent surface damage during ocean transit
- Oiled surface treatment pipes wrapped in waterproof paper to preserve anti-corrosion coating through humid climate shipping
- 6 m and 12 m standard lengths loaded in 20ft or 40ft containers with optimized stowage plans to maximize payload while preventing bundle shift
- Custom cut-to-length service available for project-specific requirements, with cut ends deburred and protected against corrosion
- Each bundle marked with heat number, steel grade (Q235/Q345/S-series), outer diameter, and wall thickness for site identification
- FOB, CIF, and DDP shipping terms available with door-to-door logistics coordination for EPC project sites
How to Initiate Procurement for Your ERW Pipe Requirement
Submit your project specifications including outer diameter, wall thickness, steel grade (Q235/Q345 or S-series equivalent), total quantity, and destination port. Our engineering team responds within 24 hours with a detailed quotation covering material cost, fabrication processing (if required), surface treatment, packing, and shipping — along with a mill test certificate sample and production timeline. For projects requiring third-party inspection or specific certification documentation, confirm these requirements at the inquiry stage to ensure full compliance with your project’s quality plan.
Frequently Asked Questions
Q: How do Q235 and Q345 grades compare to S235JR and S355JR for international projects?
A: Q235 and S235JR both provide approximately 235 MPa minimum yield strength, making them functionally equivalent for general structural applications. Q345 and S355JR offer approximately 345 MPa minimum yield strength for higher load requirements. The key difference is that S-series grades include impact toughness testing at specified temperatures (0°C for JR suffix), which may be required for European projects under EN 10219. We supply both series and provide cross-reference documentation for customs and engineering approval.
Q: Can you provide mill test certificates that satisfy third-party inspection requirements?
A: Yes. Every ERW welded round steel pipe bundle is accompanied by a mill test certificate issued by our integrated laboratory, documenting chemical composition, tensile properties, and dimensional inspection results. The certificate includes heat numbers that trace back to the original steel production batch. For projects requiring independent verification, we coordinate with SGS or BV for third-party inspection at our facility before shipment.
Q: What processing services are available beyond standard pipe supply?
A: Our in-house fabrication workshop provides CNC cutting to project-specific lengths, punching for bolt holes or branch connections, and welding per qualified procedures (WPS/PQR documented). This allows delivery of pre-fabricated pipe components rather than raw lengths, reducing on-site labor and welding qualification requirements. Processing services are quoted alongside material supply based on your shop drawings.
Q: How do you control wall thickness tolerance to avoid negative tolerance issues?
A: Our ERW welded round steel pipe production maintains ±1% tolerance on wall thickness, verified by ultrasonic thickness gauges at multiple points around the pipe circumference and along the length. We invoice by theoretical weight based on nominal dimensions, but our quality control ensures that actual wall thickness does not fall below minimum specification at any point. Mill test certificates include dimensional inspection results for verification.
Q: What is the minimum order quantity and typical production lead time?
A: The minimum order quantity is 15 tons, which allows efficient mill campaign scheduling for your specified steel grade and dimensions. Standard production lead times apply once the contract is signed and shop drawings (if applicable) are approved. For urgent project requirements, we maintain raw material inventory in Q235, Q345, and S-series grades across multiple diameter ranges to expedite production start.
Request Your ERW Welded Round Steel Pipe Quotation
Send your project specifications — outer diameter, wall thickness, steel grade, quantity, and destination — to receive a detailed quotation with mill test certificate documentation and production timeline.
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
