Description
Factory-Direct ERW Hollow Sections — Every Q235 and Q345 ASTM ERW square rectangular steel tube supplier shipment leaves Jinan with original mill test certificates and container loading plans optimized for 6-meter lengths.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 ERW Square & Rectangular Steel Tube |
| Product Type | Square / Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Square / Rectangular |
| Size Range | 300×300mm and custom sizes per request |
| Length | 6m standard, customizable |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Ends | Plain (default) |
| Application | Structure Pipe, Oil Pipe, Gas Pipe, Fluid Pipe, Boiler Pipe, Drill Pipe, Chemical Fertilizer Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, roof truss systems |
| Oil & Gas | Low-pressure fluid transport lines, gas distribution pipes |
| Industrial Machinery | Equipment frames, conveyor structures, machine bases |
| Chemical & Fertilizer | Chemical fertilizer pipeline systems, process fluid pipes |
| Boiler & Pressure | Boiler tube supports, drill pipe casings |
What Dimensional Tolerance Actually Costs on a 300mm Structural Frame Order
A ±1% tolerance on a 300×300mm ERW square tube means up to 3mm deviation per side — enough to misalign bolt holes across a multi-bay frame.
I once watched a site crew spend two days grinding weld tabs because the incoming hollow sections didn’t sit flush at the node plate. The supplier’s catalog said “standard tolerance,” but nobody checked what that meant against the drawing. On a structural frame with dozens of connections, cumulative deviation turns into rework that costs more than the steel itself. Global buyers sourcing an ASTM ERW square rectangular steel tube supplier need to confirm tolerance values in writing before the contract — not discover them at the fitting stage. [NEED_CITE: dimensional tolerance requirements for structural hollow sections per ASTM A500]
How ERW Hollow Sections Match Structural Frame and Pipeline Demands
The Q235 and Q345 grades in this ASTM ERW square rectangular steel tube supplier range cover the yield strength band that most building frames and industrial support structures require. Q235 handles general construction framing where moderate load capacity suffices, while Q345 steps up for heavier column and beam applications. The ERW process produces a continuous longitudinal weld that, when controlled properly, delivers consistent strength along the full 6-meter length. Hot-rolled surface with light oiling protects the tube during ocean transit without adding cost — and the oil washes off easily before painting or galvanizing at the destination.
Engineering Compliance and Certification Requirements
Structural hollow sections destined for regulated markets must carry traceable documentation that matches the steel grade on the drawing. For North American projects, ASTM conformance is non-negotiable — the ASTM ERW square rectangular steel tube supplier must provide mill certificates showing chemical composition and mechanical test results per the specified standard. European buyers often need CE marking under EN 10210 or EN 10219, which requires factory production control audits. [NEED_CITE: CE marking requirements for structural steel hollow sections under EN 10210] Missing or mismatched certificates cause customs holds that delay entire project schedules. Our production lines carry ISO 9001:2015 certification, Lloyd’s CE (EN 10210/10219), and FPC certification — every batch ships with original mill test certificates, and SGS or BV third-party inspection is available on request.
Steel Grade Selection and ERW Welding Process Explained
The Q-series grading system (Q195 through Q345) follows the Chinese standard convention where the number indicates minimum yield strength in MPa. Q195 and Q215 suit light structural and fencing applications; Q235 is the workhorse grade for general construction frames and fluid pipes; Q345 provides higher strength for load-bearing columns and heavier structural members. ERW (Electric Resistance Welded) tubing is formed from hot-rolled coil through continuous rolling and welded by electrical resistance heating — no filler metal is added. This makes ERW more cost-effective than seamless for structural and low-to-medium pressure applications, while maintaining reliable weld integrity when production controls are tight. The ±1% tolerance on our lines means wall thickness and outer dimensions stay within the band that fabricators expect for fit-up accuracy. Light oiling after the hot-rolling pass prevents surface oxidation during storage and transit, preserving the mill finish until the tube reaches the job site.
Hidden Costs of Sourcing the Wrong Grade or Unverified Tolerance
Ordering Q235 when the drawing calls for Q345 means the structure may pass visual inspection but fail load testing — a scenario that forces complete section replacement, not just rework. Similarly, wall thickness that drifts beyond the stated tolerance reduces the section modulus and compromises structural calculations. [NEED_CITE: consequences of wall thickness deviation on structural hollow section load capacity] Certification gaps create a different kind of cost: shipments held at port because the mill test certificate doesn’t match the declared steel grade, or because CE documentation is missing for European customs. These delays compound into demurrage charges, idle crane time, and strained contractor relationships — all traceable back to a sourcing decision made months earlier.
Why Buyers Choose Xin Jiyuan as Their ASTM ERW Square Rectangular Steel Tube Supplier
We run three production lines simultaneously in Jinan with monthly capacity exceeding 20,000 tons, which means your order doesn’t wait behind someone else’s. Every tube is measured with a calibrated caliper before loading — I personally oversee this because I’ve seen what happens when suppliers skip the step. Our inventory covers 2,800+ specifications across square, rectangular, round, and section steel, so if your project needs tubes, beams, and plates in one container, we consolidate the loading instead of shipping three partial containers from three different yards. Factory-direct pricing means no trading company margin, and volume discount programs reward partners who commit to recurring orders. Third-party inspection by SGS or BV is arranged on request, and our export team handles documentation, customs paperwork, and container loading optimization so that 6-meter tubes fit the container without wasted space.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition and mechanical properties per ASTM A213 and DIN EN 10217-1
- CE certificate covering EN 10210/EN 10219 for European market structural hollow section compliance
- ISO 9001:2015 quality management system certificate for production process traceability
- SGS or BV third-party inspection report available upon request for pre-shipment quality verification
- Material traceability by heat number linking each bundle to its original coil and production batch
- Full customs document package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q235/Q345 ERW square and rectangular tubes bundled with steel strips and edge protectors to prevent surface damage during handling
- Hot-rolled surfaces with light oiling applied before bundling to prevent rust formation during ocean transit
- Container loading plans optimized for 6-meter standard lengths, maximizing payload per 20ft and 40ft containers
- Custom cut-to-length service available for projects requiring non-standard lengths beyond the 6m default
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability
- FOB, CIF, and DDP shipping terms available with professional export documentation and real-time tracking
Start Your Procurement with Verified Specifications
Send your drawing specs, steel grade, quantity, and destination port — we respond within 12 hours with a bulk quote, production lead time, and sample mill test certificate for your records. If your project requires non-standard sizes or mixed-product container loading, we’ll confirm feasibility and provide a consolidated packing plan before you commit.
Get Your ASTM ERW Hollow Section Quote with Mill Test Certificates
Submit your specifications via email or WhatsApp to receive factory-direct pricing, tolerance confirmation, and third-party inspection options for your next structural steel order.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
