Description
Factory-Direct ERW Pipe — Raw steel to finished pipe under one roof
When procurement teams source Q235 Q355 ERW welded steel pipe from a trading company, they inherit the same material traceability gaps and coating inconsistencies I used to see in the lab. We run our own steel production lines and fabrication workshop, so every Q235 Q355 ERW welded steel pipe leaving Jinan carries a single quality system from billet to bundle.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q355 S355JR ERW Steel Pipe |
| Product Type | ERW / Welded Steel Pipe (Round) |
| Steel Grade | Q195, Q235, Q345 (Q355), S355JRH, SS400, A53-A369, ST35-ST52 |
| Standard | API 5L, ASTM A53, ASTM A671, ASTM A252, ASTM A450, ASME B36.10M, BS 1387, BS EN10296, BS 6323, BS 6363, BS EN10219, GB/T 3091, GB/T 13793, GB/T 9711 |
| Section Shape | Round |
| Outer Diameter | 10–700 mm |
| Wall Thickness | Cold rolled 1–4.0 mm / Hot rolled 4–20 mm |
| Length | 1–12 m (standard 6 m / 6.4 m / 12 m) |
| Technique | ERW / Hot Rolled / Cold Rolled |
| Surface Treatment | Hot Rolled / Hot Dip Galvanized (Zinc Coated 200–700 g/m²) / Slightly Oiled |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded |
| Application | Fluid transport / Structural / Construction / Scaffolding / Fencing / Machinery / Industrial piping |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding tubes, piling pipes, foundation casings |
| Industrial Piping | Oil and gas transport, water supply lines, chemical fertilizer pipelines |
| EPC & General Contracting | Structural pipe packages for warehouses, power plants, and logistics centers |
| Machinery & Equipment | Conveyor structures, hydraulic cylinder sleeves, machine frames |
| Fencing & Agriculture | Fence posts, greenhouse frames, irrigation systems |
What Wall-Thickness Tolerance Costs on a Q235 Q355 ERW Welded Steel Pipe Order
A ±1% tolerance on a 700 mm OD pipe is the difference between passing third-party inspection and scrapping an entire container.
Overseas buyers routinely discover that the mill cert says 4.0 mm but the caliper reads 3.5 mm — a 12% negative deviation that fails EN 10219 dimensional checks at port [NEED_CITE: EN 10219 cold-formed and hot-formed hollow section tolerance requirements]. When the fabricator sources raw material from a third-party mill and outsources pipe-making to another shop, nobody owns that tolerance gap. We control the entire chain: our own steel production feeds directly into our ERW welding line, so every Q235 Q355 ERW welded steel pipe is checked against the same WPS and the same dimensional protocol before it leaves the workshop.
Matching Q235 Q355 ERW Welded Steel Pipe to Structural and Fluid Applications
Round ERW pipe in the 10–700 mm OD range covers everything from scaffolding uprights to piling casings. For structural frames, Q355 and S355JRH grades deliver the yield strength that engineers specify under EN 1993 and AISC load combinations, while the ±1% OD tolerance keeps connection plates and gusset fits tight on site. In fluid transport — water, gas, low-pressure oil — the ERW weld seam undergoes in-line NDT per API 5L and ASTM A53, and hot-dip galvanizing at 200–700 g/m² zinc coating handles atmospheric and mild soil corrosion without field painting. EPC contractors sourcing Q235 Q355 ERW welded steel pipe from us get one set of documentation covering both material and fabrication, which eliminates the finger-pointing between steel supplier and pipe mill.
Engineering Compliance: From EN 10219 Customs Clearance to ASTM Mill Certs
EU projects demand CE marking under EN 10219 for structural hollow sections; without it, customs holds the shipment regardless of the pipe’s actual quality [NEED_CITE: CE marking requirements for structural steel under EN 10219]. Middle East and African infrastructure specs often call up ASTM A53 or API 5L, and the chemical composition must match the heat number on the mill test certificate. Our Q235 Q355 ERW welded steel pipe is produced to the full standard matrix — GB/T 3091 for domestic-grade fluid lines, BS EN 10219 for European structural work, ASTM A53 for North American piping — and every heat is traceable from billet to bundle. Custom lengths of 6 m, 6.4 m, or 12 m reduce on-site welding and fit the standard 20ft and 40ft open-top containers without overhang.
Steel Grade Selection: Q235 vs Q355 vs S355JR — What the Designation Actually Means
Q235 and S235JR are roughly equivalent in yield behavior, both sitting around 235 MPa nominal, making them the default choice for non-critical structural framing, scaffolding, and fencing. Q355 and S355JRH step up to 355 MPa class, which is where engineers specify for load-bearing columns, crane beams, and piling. The ASTM A53–A369 range covers the same territory in the American system, with A53 Grade B being the most common equivalent to Q235 for general piping. ERW welding joins the strip edges under controlled pressure and current, producing a seam that — when paired with in-line ultrasonic testing — performs comparably to seamless pipe at a fraction of the cost for diameters above 219 mm. Hot-dip galvanizing at 200–700 g/m² zinc adds corrosion resistance that plain oiled or black pipe cannot match in coastal or industrial atmospheres, while the ±1% tolerance on OD and wall thickness keeps theoretical weight calculations aligned with actual delivered weight.
The Hidden Cost of Buying Q235 Q355 ERW Welded Steel Pipe Without Verified Documentation
A pipe that arrives at site with a mill cert but no heat-number traceability will fail EN 10204 3.1 inspection and delay project handover [NEED_CITE: EN 10204 inspection document types for steel products]. Negative tolerance beyond the standard ±1% means the structural engineer’s load calculations no longer apply — the pipe may pass visually but will not carry the design load. Coating thickness below the specified 200 g/m² zinc on galvanized pipe accelerates corrosion in marine environments, turning a five-year maintenance cycle into an eighteen-month one. Certification gaps — missing CE marks for EU, missing API monograms for oil and gas — mean customs rejection or client rejection, and the cost of return shipping or on-site re-fabrication dwarfs the original price difference between a verified supplier and an unverified one.
Why Procurement Teams Source Q235 Q355 ERW Welded Steel Pipe From XJY Structure
We operate our own steel production facility with three rolling lines and over 2,800 raw material specifications in stock, which means the Q235 Q355 ERW welded steel pipe you order is made from billet we melted and rolled — not bought from a third-party mill with unknown heat history. Our fabrication division handles CNC cutting, drilling, welding, and shot blasting under the same ISO 9001 system, so shop drawings, material optimization, and welding sequences stay coordinated. Every Q235 Q355 ERW welded steel pipe ships with a full quality documentation package: WPS, PQR, weld maps, dimensional inspection reports, and coating thickness measurements. We hold CE certification under EN 10219 for the European market and accept SGS, BV, or TÜV third-party inspection before shipment. Our welding procedures and welders are certified to AWS and EN standards, and we have delivered structural steel packages to projects across the EU, Middle East, Southeast Asia, and Africa.
Documentation & Compliance
- Mill Test Certificate documenting Q235/Q355/S355JR chemical composition and mechanical properties per EN 10204 3.1, with full heat-number traceability
- CE certificate under EN 10219 for structural hollow sections exported to EU member states
- ISO 9001 quality management certificate covering both steel production and ERW pipe fabrication
- SGS or BV third-party inspection report verifying OD, wall thickness, zinc coating weight, and weld seam quality before shipment
- Material traceability report linking each bundle to its heat number, chemical analysis, and tensile test results
- Customs documents including packing list, bill of lading, and certificate of origin formatted for destination-country clearance
Packaging, Loading & Delivery
- Q235 Q355 ERW welded steel pipe bundled with high-tensile steel strips and edge protectors to prevent coating damage during ocean transit
- Hot-dip galvanized pipes wrapped with waterproof cloth and separated by rubber spacers to preserve the 200–700 g/m² zinc coating
- Standard 6 m and 12 m lengths loaded into 20ft and 40ft open-top containers with optimized nesting for OD 10–700 mm range
- Custom cut-to-length service available for 6.4 m and project-specific dimensions, with ends plain, beveled, or threaded per drawing
- Each bundle tagged with heat number, steel grade (Q235/Q355/S355JR), OD, wall thickness, and standard designation for site identification
- FOB, CIF, and DDP terms available with professional oversized-cargo loading plans and door-to-door tracking to project site
Getting Your Q235 Q355 ERW Welded Steel Pipe Quote Started
Send your project drawings (PDF or DWG), steel grade specification, quantity, and destination port — we respond within 24 hours with a detailed quotation covering material, fabrication, coating, packing, and shipping, plus a shop drawing timeline and production schedule. If you need non-standard dimensions, custom lengths, or specific certification packages for EU or Middle East customs, we will confirm feasibility and lead time before you commit.
Request a Quotation with Mill Test Certificate
Submit your specifications, steel grade, and destination to receive a detailed quotation and sample mill test certificate within 24 hours.
Mobile / WhatsApp / WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Website: www.xjystructure.com
Frequently Asked Questions
Q: How do Q235, S235JR, and A36 compare — which grade should I specify?
A: Q235 (GB/T 700), S235JR (EN 10025), and A36 (ASTM A36) are broadly equivalent in yield strength and chemical composition for general structural and piping applications. Q355 and S355JRH step up to the 355 MPa class for heavier structural work. We supply all three systems and provide cross-reference documentation so your engineer can confirm equivalence for your specific design code.
Q: Can I arrange third-party inspection before shipment?
A: Yes. We accept SGS, BV, and TÜV inspection at our facility before loading. The inspector verifies OD, wall thickness, zinc coating weight (for galvanized pipe), weld seam quality, and dimensional tolerance against the applicable standard. The full inspection report is included in the shipping documentation package.
Q: What is the difference between hot-dip galvanized, oiled, and black (hot-rolled) surface finish?
A: Hot-dip galvanizing applies a 200–700 g/m² zinc coating for long-term corrosion resistance in atmospheric, marine, or buried conditions. Slightly oiled black pipe is suitable for indoor or short-term outdoor use where painting or additional coating will be applied on site. Hot-rolled black pipe without oil is the most economical option for structural applications where the pipe will be enclosed or painted after installation.
Q: Do your pipes carry CE marking for EU projects?
A: Yes. Our structural hollow sections are certified under EN 10219, which is required for CE marking of steel structures in the European Union. We provide the CE certificate, Declaration of Performance, and full mill test documentation formatted for EU customs and client handover.
Q: What is the theoretical weight versus actual weight, and how does negative tolerance affect my order?
A: Theoretical weight is calculated from nominal OD, wall thickness, and length using the standard density of steel. Actual weight may vary within the ±1% tolerance specified in the applicable standard. We quote by theoretical weight unless otherwise agreed, and our production controls keep negative tolerance well within standard limits — verified by in-line measurement and third-party inspection when required.
