Description
Direct Mill Supply, Full Traceability — Every Q235 Q345 A36 ERW welded steel pipe we ship carries a heat number traceable back to our own steel mill slab, eliminating third-party material gaps.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 A36 ERW Welded Steel Pipe |
| Product Type | ERW Welded Steel Pipe (Round) |
| Steel Grade | Q195, Q235, Q345 (Q355), A36, S355, 10#, 20#, 45#, 16Mn, A53, A106, ST35, ST52 |
| Standard | API 5L, ASTM A53, ASTM A106, ASTM A252, ASTM A523, ASTM A671, ASME B36.10M, BS 1387, BS EN 10296, BS EN 10219, BS 6323, BS 6363, GB/T 3091, GB/T 13793, GB/T 9711 |
| Section Shape | Round |
| Outer Diameter | 6–1820 mm |
| Wall Thickness | Cold rolled 1–4.0 mm; Hot rolled 4–20 mm |
| Length | 1–12 m (standard 6 m / 12 m) |
| Technique | ERW / Hot Rolled / Cold Rolled / Cold Drawn |
| Surface Treatment | Hot Rolled, Slightly Oiled |
| Tolerance | ±1% |
| Ends | Plain (default) |
| Application | Fluid transport, Boiler, Gas & Oil pipeline, Hydraulic system, Chemical fertilizer, Construction, Machinery, Building industry |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC & Industrial Construction | Structural steel frames for warehouses, factory buildings, and process pipe racks |
| Oil & Gas Pipeline | Low-pressure fluid transport lines, gathering pipelines, and distribution networks |
| Infrastructure & Municipal | Scaffolding tubes, piling casings, and water conveyance systems |
| Machinery & Equipment | Hydraulic cylinders, mechanical tubing, and conveyor structural members |
| Chemical & Fertilizer Plant | Process piping for non-corrosive media and utility lines |
What Negative Tolerance Actually Costs on a Welded Pipe Order
A ±1% OD tolerance means nothing if wall thickness drifts beyond mill cert limits.
I once watched a container of large-diameter welded pipe get rejected at port re-inspection because the actual weight ran nearly two tons below theoretical — the wall had been rolled to the absolute floor of negative tolerance, and the buyer’s third-party inspector flagged it before the cargo ever reached site. On a Q235 Q345 A36 ERW welded steel pipe order, that kind of discrepancy doesn’t just hurt your budget; it triggers re-inspection holds, demurrage charges, and in worst cases, a full rejection at destination [NEED_CITE: weight tolerance and invoicing practices in international steel trade]. When your fabricator sources pipe from a trader who sources from a rolling mill you’ve never audited, the chain of accountability breaks at the first discrepancy.
Matching Wall Thickness and Grade to Structural Load Paths
A Q235 Q345 A36 ERW welded steel pipe in the 6–1820 mm OD range covers everything from thin-wall fluid lines to thick-wall structural columns. For EPC warehouse frames, Q345 (Q355) in hot-rolled wall thickness above 6 mm provides the yield margin that structural engineers specify for primary load-bearing members. For scaffolding and secondary structures, Q235 in cold-rolled 1–4 mm wall keeps weight and cost down while meeting GB/T 3091 requirements. Our own rolling lines produce the raw coil, and our fabrication shop cuts, welds, and drills the same pipe — so when a project needs a 325 mm × 10 mm column cut to 5.8 m with base plates welded on, that workflow stays under one quality system from slab to finished component.
Engineering Compliance and Certification Pathways
Structural pipe used in load-bearing frames must comply with the relevant design code — EN 1993-1-1 for European projects, AISC 360 for North American work, and GB 50017 for domestic Chinese engineering. The Q235 Q345 A36 ERW welded steel pipe we supply meets BS EN 10219 for cold-formed welded structural hollow sections and ASTM A53 / A500 for American-spec structural tube, with mill test certificates issued per EN 10204 3.1 [NEED_CITE: EN 10219 cold-formed structural hollow section certification requirements]. For EU-bound shipments, CE marking under EN 10210 / EN 10219 is mandatory for customs clearance, and we provide the full Declaration of Performance documentation. Third-party inspection by SGS, BV, or TÜV is accepted at our facility before shipment, giving EPC procurement teams an independent verification checkpoint.
Understanding Grade Equivalence and Process Selection
The Q-series (Q195, Q235, Q345) follows the Chinese GB system where the number indicates minimum yield strength in MPa; A36 and A53 follow ASTM; S355 follows EN 10025. These grades are not identical but have recognized equivalence mappings — Q235 broadly aligns with S235JR and A36 in yield range, while Q345 maps to S355JR and ASTM A572 Gr.50 in structural applications [NEED_CITE: steel grade equivalence between GB, EN, and ASTM standards]. ERW welding produces a longitudinal seam suited to medium-diameter pipe up to 1820 mm OD at lower cost than seamless, making it the standard choice for structural and fluid transport applications below high-pressure thresholds. Hot-rolled wall thickness (4–20 mm) serves structural and heavy-wall process piping, while cold-rolled (1–4 mm) fits thin-wall mechanical and furniture tubing. The slightly oiled hot-rolled surface provides short-term rust prevention during transit; for long-term corrosion exposure, options include hot-dip galvanizing, 3PE coating, or site-applied paint systems.
Hidden Costs of Sourcing Without Mill Traceability
When a buyer receives a Q235 Q345 A36 ERW welded steel pipe with no heat-number traceability or a mill cert that doesn’t match the physical markings, the consequences cascade: customs authorities in the EU and Middle East increasingly reject shipments lacking EN 10204 3.1 documentation, project inspectors flag material for re-testing at the buyer’s expense, and structural engineers cannot sign off on load calculations without verified chemistry and mechanical data [NEED_CITE: material certification requirements for structural steel in international construction projects]. A pipe that arrives with wall thickness at the extreme negative tolerance may pass visual inspection but fail ultrasonic testing, forcing costly rework or replacement after the cargo has already crossed oceans. The real cost isn’t the per-ton price difference — it’s the schedule delay and the engineering liability.
Why Procurement Teams Source This Pipe From Our Mill
We operate our own steel production facility with three rolling lines and maintain over 2,800 raw material specifications in stock — meaning the Q235 Q345 A36 ERW welded steel pipe you order is rolled from slab we control, not sourced from a trader’s spot market allocation. Our fabrication division handles downstream processing: CNC cutting, MIG/MAG/SAW welding, shot blasting, and painting, so structural components arrive fabrication-ready with shop drawings reviewed and approved before production begins. Every heat carries full traceability from slab chemistry through finished pipe dimensions, documented in mill test certificates compliant with EN 10204 3.1 / 3.2. We hold ISO 9001 certification, CE marking for EN 10219 / EN 10210 structural hollow sections, and accept third-party inspection by SGS, BV, and TÜV. Our loading team plans container stowage for oversized and heavy-wall pipe to prevent transit damage, and we handle complete export documentation including certificate of origin for preferential customs treatment in destination countries.
Documentation & Compliance
- Mill test certificate documenting Q235 / Q345 / A36 chemical composition and mechanical properties per EN 10204 3.1, with heat number traceable to original slab
- CE certificate and Declaration of Performance for BS EN 10219 cold-formed structural hollow sections, required for EU customs clearance
- ISO 9001 quality management system certificate covering the full production chain from raw steel rolling through ERW pipe fabrication
- SGS / BV / TÜV third-party inspection report available upon request, covering dimensional checks, weld seam NDT, and coating thickness
- Material traceability sheet linking each pipe’s heat number to its chemical analysis, tensile test results, and wall thickness measurements
- Full customs document package: commercial invoice, packing list, bill of lading, and certificate of origin for destination-country tariff treatment
Packaging, Loading & Delivery
- ERW welded pipe bundled with galvanized steel strips at intervals matched to the 6 m / 12 m standard length, with end caps on plain-end pipes to prevent edge damage during handling
- Hot-rolled slightly oiled surface preserved by waterproof wrapping for ocean shipment, preventing flash rust during transit to Middle East and Southeast Asian ports
- Container loading plans optimized for the 6–1820 mm OD range, with nested small-diameter pipe inside large-diameter pipe to maximize 20ft and 40ft GP utilization
- Custom cut-to-length service available within the 1–12 m range, with cut ends deburred and re-oiled before bundling
- Each bundle tagged with heat number, steel grade (Q235 / Q345 / A36), OD × wall thickness, and length for site identification
- Delivery terms FOB / CIF / DDP with typical production lead times confirmed at order, and full tracking from mill to destination port
Getting Your Quotation and Mill Documentation
Send your project drawings or pipe schedule specifying steel grade, outer diameter, wall thickness, length, quantity, and destination port — we respond within one working day with pricing, mill test certificate samples, and a production timeline. For non-standard OD or wall thickness outside the 6–1820 mm / 1–20 mm range, we review feasibility against our rolling mill capabilities and confirm lead time before you commit. If your project requires CE marking, third-party inspection, or specific end treatment, flag it at inquiry stage so we include it in the quotation package.
Frequently Asked Questions
Q: How do Q235, A36, and S235JR compare — can they be substituted?
A: Q235, A36, and S235JR share overlapping yield strength ranges and are widely used as structural carbon steel grades, but they follow different standard systems (GB, ASTM, EN respectively). Substitution depends on the project’s governing design code and the engineer’s approval. We supply all three grades and can provide cross-reference documentation showing chemical composition and mechanical property comparisons for your engineer’s review.
Q: What documentation comes with each shipment?
A: Every shipment includes a mill test certificate per EN 10204 3.1 showing chemical composition and mechanical properties for each heat number, along with a packing list, commercial invoice, bill of lading, and certificate of origin. CE certificates and Declaration of Performance are provided for EU-bound orders. Third-party inspection reports from SGS, BV, or TÜV are available if requested before shipment.
Q: Can you produce non-standard OD or wall thickness?
A: Our rolling lines cover 6–1820 mm outer diameter with wall thickness from 1 mm (cold rolled) to 20 mm (hot rolled). For sizes outside these ranges, we review feasibility case by case. MOQ for standard sizes is 5 tons; non-standard or custom-length orders may have higher minimums depending on the rolling schedule.
Q: How does invoicing work — theoretical weight or actual weight?
A: We can invoice by theoretical weight or actual weight depending on your preference and the order agreement. The ±1% tolerance on our Q235 Q345 A36 ERW welded steel pipe means the variance between theoretical and actual weight stays within a narrow band. We recommend agreeing on the invoicing method before contract signing to avoid disputes at destination.
Q: What surface treatment options are available?
A: Standard delivery is hot-rolled with slight oiling for short-term rust prevention. For corrosive environments or long-term outdoor exposure, we offer hot-dip galvanizing, 3PE anti-corrosion coating, or custom paint systems. The choice depends on the application environment, design life, and project specification.
Get Your Q235 Q345 A36 ERW Welded Steel Pipe Quote with Full Mill Certification
Submit your pipe schedule, steel grade, and destination port — we return pricing, mill test certificate samples, and production timeline within one working day.
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
