Description
Factory-Direct ERW Rectangular Tubes — Every Q235/Q345 ASTM rectangular steel tube ERW welded hollow section supplier shipment leaves Jinan with original mill certificates and third-party inspection readiness.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 Rectangular ERW Steel Tube |
| Product Type | Rectangular Steel Tube (ERW Welded Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1, BIS |
| Section Shape | Rectangular (Square and Round also available) |
| Outer Diameter or Side Length | 300×300 mm (full range per inquiry) |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Custom (per customer request) |
| Processing Services | Welding, Punching, Cutting, Bending, Decoiling |
| Ends | Plain (default) |
| Invoicing | By Theoretical Weight |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe, Steel Structures, Construction Frames, Machinery, Scaffolding |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, roof trusses, bridge handrails |
| Industrial Piping | Fluid transport lines, gas distribution, oil conveyance, chemical fertilizer pipelines |
| Machinery & Equipment | Conveyor structures, crane booms, equipment base frames |
| Scaffolding & Temporary Works | Load-bearing scaffolding uprights, cross bracing, support towers |
What Dimensional Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a 300×300 ERW rectangular hollow section keeps field-fit welding gaps within structural code limits.
When buyers receive welded tubes with wall thickness drifting beyond acceptable negative tolerance, the consequences cascade: connection plates no longer align, bolt holes miss their targets, and on-site rework eats into project margins. I have seen entire container loads of rectangular tubes rejected at site because the actual wall thickness fell short of the nominal value printed on the packing list. For any ASTM rectangular steel tube ERW welded hollow section supplier, dimensional consistency is not a marketing point — it is the difference between a frame that goes up on schedule and one that triggers a structural engineer’s re-inspection. [NEED_CITE: EN 10219 cold-formed welded hollow section dimensional tolerance requirements]
Matching ERW Rectangular Tubes to Structural and Industrial Loads
The Q235 and Q345 grades in this ASTM rectangular steel tube ERW welded hollow section supplier range cover the yield strength band most frequently specified for building frames, machinery bases, and scaffolding uprights. Q235 serves general structural work where moderate load-bearing is required, while Q345 steps up the yield point for heavier column and beam applications. The ERW welding process produces a continuous longitudinal seam that, when controlled under DIN EN 10217-1 parameters, delivers weld integrity comparable to the parent metal — critical when tubes are cut, punched, or bent during fabrication. Hot-rolled finish with light oiling protects the surface during ocean transit without adding coating cost that galvanized or painted finishes would carry.
Engineering Compliance and Certification Pathways
Structural projects in the European market require CE marking under EN 10210 (hot-finished) or EN 10219 (cold-formed welded hollow sections), and the ASTM rectangular steel tube ERW welded hollow section supplier documentation package must trace every batch to its heat number for auditor verification. North American projects referencing ASTM A500 or A213 expect mill test certificates that confirm chemical composition and mechanical test results against those standards. For BIS-regulated markets, the same production lines can supply certified material with Indian standard compliance documentation. The ±1% tolerance on side lengths and wall thickness aligns with international hollow section standards, reducing the risk of customs holds or third-party inspection failures. [NEED_CITE: steel grade equivalence mapping between Q-series, ASTM, and EN standards]
Steel Grade Selection and ERW Process Fundamentals
The Q-grade system (Q195 through Q345) follows the Chinese standard convention where the number after “Q” indicates the minimum yield strength in MPa. Q195 and Q215 suit light structural and non-load-bearing applications; Q235 is the workhorse grade for general construction frames and scaffolding; Q345 provides higher yield strength for columns, heavy machinery bases, and bridge components. ERW welding forms the tube by rolling a steel strip into a rectangular profile and fusing the seam through electric resistance heating — no filler metal is added, which keeps the weld zone narrow and the dimensional profile consistent along the full length. This process is cost-effective for medium-wall rectangular and square sections, and it produces a smooth exterior surface that accepts paint, galvanizing, or direct exposure with light oiling. Wall thickness tolerance directly affects theoretical weight invoicing: a tube measured at the lower edge of the ±1% band weighs less per meter, which matters when procurement is billed by theoretical weight rather than actual scale weight.
The Hidden Cost of Unverified Tolerances and Missing Certificates
Pricing that looks attractive on paper can mask hidden costs when wall thickness runs consistently at the extreme negative edge of tolerance, or when mill test certificates cannot be traced to a specific heat number. Project inspectors who discover undocumented material face three options: reject the shipment at the port, order destructive testing at the buyer’s expense, or accept the material under a formal deviation — each option carrying delay penalties and reputational risk. [NEED_CITE: consequences of non-compliant steel tube documentation in international construction projects] An ASTM rectangular steel tube ERW welded hollow section supplier that controls tolerance at every production stage and provides heat-number traceability eliminates these variables before the container is sealed.
Why Procurement Teams Source ERW Rectangular Tubes from Xin Jiyuan
Three dedicated production lines run simultaneously, delivering monthly capacity above 20,000 tons of welded hollow sections across rectangular, square, and round profiles. Every batch of Q235 and Q345 material passes through an in-house laboratory at three inspection stages — incoming strip, post-weld dimensional check, and final surface and certificate verification. The ASTM rectangular steel tube ERW welded hollow section supplier inventory covers 2,800+ specifications, meaning standard sizes ship from ready stock while custom lengths and non-standard dimensions follow typical production lead times. Factory-direct pricing removes intermediary margins, and volume discount programs reward long-term procurement partnerships. CE certification under EN 10210 and EN 10219, ISO 9001:2015 registration, and FPC (Factory Production Control) compliance ensure that every shipment meets the documentation requirements of European, American, and Asian markets. Professional export teams handle container loading optimization — critical when 300×300 rectangular tubes must be nested efficiently to maximize payload per 20-foot or 40-foot unit.
Documentation & Compliance
- Mill Test Certificate documenting Q235/Q345 chemical composition and mechanical properties per ASTM A213 and DIN EN 10217-1, traceable to heat number
- CE certificate covering EN 10210 hot-finished and EN 10219 cold-formed welded hollow sections for European market compliance
- ISO 9001:2015 quality management certificate covering the full ERW rectangular tube production process
- SGS or BV third-party inspection report available on request, conducted before container loading at the Jinan facility
- Material traceability documentation linking each bundle to its heat number, production date, and test results
- Customs document package including packing list, bill of lading, and certificate of origin formatted for the destination country
Packaging, Loading & Delivery
- Q235/Q345 rectangular tubes bundled with steel strips and edge protectors to maintain the ±1% dimensional profile during ocean transit
- Hot-rolled surface with light oiling applied before bundling to prevent rust formation without interfering with downstream painting or galvanizing
- Container loading plans optimized for 300×300 mm and other rectangular profiles, nesting tubes to maximize payload within 20GP and 40GP units
- Custom cut-to-length service available, with bundled ends protected by plastic caps to prevent deformation during handling
- Heat number and steel grade stenciled on each bundle for site identification and traceability verification
- FOB, CIF, and DDP shipping terms supported, with professional documentation handling for customs clearance at the destination port
Starting Your ERW Rectangular Tube Procurement
Submit your specification sheet — including section dimensions, wall thickness, steel grade, total tonnage, and destination port — to receive a competitive bulk quotation with volume pricing, production lead time, and a sample mill test certificate for quality verification. Non-standard dimensions, custom lengths, and pre-fabrication services (cutting, punching, bending) are quoted separately with detailed processing timelines. The ASTM rectangular steel tube ERW welded hollow section supplier team confirms certification requirements and third-party inspection scheduling before production begins, ensuring documentation aligns with your project’s compliance framework.
Frequently Asked Questions
Q: How do Q235 and Q345 grades map to ASTM and EN equivalent standards?
A: Q235 corresponds broadly to ASTM A36 and EN S235JR in yield strength range, while Q345 aligns with ASTM A572 Grade 50 and EN S355JR. Equivalent grade consultation is available for specific project specifications, and mill test certificates confirm actual chemical and mechanical results against the standard referenced in your purchase order.
Q: What documentation accompanies each shipment of ERW rectangular tubes?
A: Every shipment includes an original mill test certificate traceable to heat number, a packing list, bill of lading, and certificate of origin. CE certificates under EN 10210/EN 10219 and ISO 9001:2015 documentation are provided for markets requiring European or international compliance. SGS or BV third-party inspection reports can be arranged before loading.
Q: What is the minimum order quantity for non-standard rectangular dimensions?
A: The standard MOQ is 5 tons. Non-standard dimensions and custom lengths are accepted, with production lead times confirmed after specification review. Trial orders of 1 ton are supported for new customers evaluating material quality before committing to bulk procurement.
Q: How is invoicing calculated — by theoretical weight or actual weight?
A: Invoicing is by theoretical weight based on the nominal dimensions and standard steel density, within the ±1% tolerance range. This method provides pricing transparency and avoids weight variation disputes during delivery.
Q: Can the tubes be pre-processed before shipment — cutting, punching, or bending?
A: Yes. In-house processing services include cutting to custom length, punching, bending, welding, and decoiling. Pre-fabrication reduces on-site labor costs and accelerates project timelines, with processing details confirmed during the quotation stage.
Request Your ASTM Rectangular Tube Quotation
Send your specification requirements — dimensions, steel grade, quantity, and destination — to receive factory-direct pricing, production timelines, and a sample mill test certificate within 12 hours.
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
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
