Description
Factory-Direct ERW Tubes, No Middlemen — 3 dedicated production lines producing Carbon Steel ERW Square Rectangular Steel Tube in Q235, Q345, S355J2 and ASTM A53 grades, shipped with full mill test certificates to 50+ countries.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Carbon Steel ERW Square & Rectangular Steel Tube |
| Product Type | Welded Square and Rectangular Steel Tube (ERW) |
| Steel Grade | Q195, Q235, Q235B, Q345, Q345B, SS400, ASTM A53 (A/B), ASTM A106 (B/C), S235JR, S275JR, S355J2 |
| Standard | ASTM A53, ASTM A106, API 5L (Gr.A, Gr.B, X42–X70), EN 10219, GB/T, JIS G3466 |
| Section Shape | Square, Rectangular |
| Size Range | 15mm × 15mm – 800mm × 800mm |
| Wall Thickness | 1mm – 50mm |
| Length | 6m, 12m (or customized) |
| Technique | ERW (Electric Resistance Welded), Hot Rolled / Cold Rolled available |
| Surface Treatment | Black Painted, Varnished, Galvanized (Hot-Dip / Electro), 3LPE/3LPP Coated, Oiled |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Grooved |
| Application | Structural frameworks, scaffolding, oil & gas pipeline, machinery, shipbuilding |
| MOQ | Negotiable |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding systems, bridge support structures |
| Oil & Gas | Pipeline transmission lines, gas distribution networks |
| Machinery Manufacturing | Hydraulic cylinder bodies, pneumatic system frames, conveyor structures |
| Shipbuilding & Offshore | Deck structures, offshore platform supports, marine piping |
| Automotive | Chassis components, exhaust system frames |
Where Certification Gaps Block Customs Clearance for Carbon Steel ERW Square Rectangular Steel Tube
Missing EN 10219 or ASTM A53 references on mill test certificates is the single most common reason structural tube shipments get held at EU and North American ports.
Procurement teams ordering ERW welded square and rectangular tubes across mixed standard systems — GB, EN, ASTM, JIS — routinely face grade confusion. A Q345B order shipped without documented equivalence to S355J2 triggers customs queries. A batch of ASTM A53 tubes arriving without a third-party inspection report gets rejected by the site engineer before unloading even begins. These documentation failures do not surface during production; they surface at the port, at the job site, and in the project delay claim. [NEED_CITE: EN 10219 cold-formed structural hollow section certification requirements]
Matching ERW Tube Dimensions to Structural Frame Requirements
Carbon Steel ERW Square Rectangular Steel Tube in 15×15mm to 800×800mm sections with wall thickness from 1mm to 50mm covers the full range from light-gauge curtain wall framing to heavy-load column members. The ±1% dimensional tolerance ensures that on-site bolt-hole alignment and welded connection details hold within engineering tolerances — a critical factor when a structural frame demands hundreds of repeating joints. Our 3 production lines cover 2,800+ specifications, meaning a single order mixing 50×50×3mm scaffolding tubes and 400×200×16mm column sections ships from one source with consistent chemistry and mechanical properties across the entire batch.
Engineering Compliance and Surface Protection for Field Conditions
Structural frames designed to EN 1993 or AISC standards require documented steel grade conformity — S235JR, S275JR, or S355J2 for European projects, ASTM A53 or A106 for North American specifications. [NEED_CITE: steel grade equivalence mapping between GB, EN, and ASTM standards] Surface treatment selection directly affects service life: hot-dip galvanizing suits outdoor scaffolding and offshore structures where zinc sacrifice protection extends field life; black painted or oiled finishes serve indoor machinery frames and indoor structural applications. For buried or submerged pipeline supports, 3LPE/3LPP coating provides barrier protection against soil-side corrosion. Lloyd’s CE certification under EN 10210 and EN 10219 ensures that every Carbon Steel ERW Square Rectangular Steel Tube shipped to EU markets carries the documentation customs authorities and project inspectors require.
Understanding ERW Welding Process and Grade Selection
Electric Resistance Welding fuses the steel strip edges under heat and pressure without filler metal, producing a weld seam with mechanical properties closely matching the parent material. This makes ERW Carbon Steel ERW Square Rectangular Steel Tube suitable for structural applications where the weld zone must carry load — scaffolding, building frames, and machinery supports. The Q-series grades (Q195–Q345) follow the Chinese GB system where the number indicates minimum yield strength in MPa; S-series grades (S235JR–S355J2) follow EN 10219 with similar yield designation; ASTM A53 Grade B and A106 Grade B serve the same structural role under the American system. Wall thickness directly governs load-bearing capacity: a 400×400×20mm section carries substantially more compressive load than a 400×400×8mm section of the same outer dimension. Negative tolerance on wall thickness reduces actual weight below theoretical calculations — our ±1% tolerance control ensures that the delivered product meets the specified minimum wall without unexpected thinning.
Hidden Costs of Incorrect Grade Specification and Missing Documentation
Ordering Q345B tubes that arrive with a mill test certificate referencing only Q235 chemistry forces the site engineer to either reject the shipment or redesign the structural connections — both options carry significant cost. A Carbon Steel ERW Square Rectangular Steel Tube shipment without CE marking under EN 10219 gets held at EU customs, incurring demurrage charges that exceed the tube cost itself. Wall thickness below the specified minimum — a common issue when suppliers run negative tolerance beyond acceptable limits — reduces the section modulus and compromises structural safety under design loads, potentially triggering failure during final inspection. [NEED_CITE: consequences of wall thickness deviation in structural hollow sections per EN 10219]
Why Project Procurement Teams Source ERW Tubes From SD XJY Pipe
Our in-house physical and chemical laboratory tests every heat for dimensional accuracy, mechanical properties, and chemical composition before release — the mill test certificate reflects actual test data, not generic template values. We hold Lloyd’s CE certification under EN 10210 and EN 10219, ISO 9001:2015, and Singapore FPC, meaning Carbon Steel ERW Square Rectangular Steel Tube shipments to regulated markets carry the correct certification from the first inquiry. Third-party inspection through SGS or BV is arranged on request, with full photographic documentation provided before container sealing. Our professional loading team uses custom cradles and edge protectors to prevent bending and surface damage during ocean transit — a detail that matters when 12-meter S355J2 tubes arrive at a European job site needing zero straightening before installation. Custom non-standard sizes, cutting, punching, and bending services are completed in our facility before shipment, reducing on-site labor and waste.
Documentation & Compliance
- Mill test certificate documenting Q235B/Q345B chemical composition and mechanical properties per GB/T standards, or S235JR/S355J2 per EN 10219, for every heat number
- CE certificate under EN 10210 and EN 10219 for Carbon Steel ERW Square Rectangular Steel Tube exported to EU member states
- ISO 9001:2015 quality management certificate covering production, testing, and dispatch processes
- SGS or BV third-party inspection report available upon request, covering dimensional checks, visual inspection, and witness testing
- Material traceability by heat number from steel strip coil through forming, welding, and final inspection
- Full customs documentation including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- ERW square and rectangular tubes bundled with high-tensile steel strips, separated by timber dunnage to prevent surface scratching during transit
- Hot-dip galvanized tubes packed with edge protectors and plastic wrapping to preserve zinc coating integrity during ocean shipping
- Container loading optimized for 6m and 12m lengths, with nested smaller sections inside larger profiles to maximize payload per 20ft or 40ft container
- Custom cutting to project-specified lengths available before shipment, reducing on-site cutting waste and labor
- Heat number and steel grade stenciled on each tube end for site identification and traceability
- FOB, CIF, and DDP shipping terms available, with door-to-door logistics coordination to 50+ countries
Submit Specifications to Receive Quotation and Mill Test Certificate
Provide your required section dimensions, wall thickness, steel grade, surface treatment, quantity, and destination port — we return a detailed quotation with unit pricing, production lead time, and shipping terms within 12 hours. Mill test certificates, third-party inspection reports, and CE documentation are confirmed in the quotation before any deposit is placed.
Request Your Carbon Steel ERW Square Rectangular Steel Tube Quotation
Send your specifications to admin@sdxjypipe.com or contact us via WhatsApp at +86 188 5315 7756 to receive pricing, certification confirmation, and delivery scheduling.
Frequently Asked Questions
Q: How do Q235/Q345 (GB) grades map to S235JR/S355J2 (EN) and ASTM A53?
A: Q235 and S235JR share similar yield strength levels and chemical composition ranges, making them functionally equivalent for most structural applications. Q345 corresponds to S355J2 under EN 10219, with both grades offering higher yield strength for heavy-load structural members. ASTM A53 Grade B serves a comparable structural role in North American specifications. We provide grade equivalence documentation with every shipment.
Q: What mill test certificates and inspection reports are included?
A: Every batch ships with a mill test certificate documenting chemical composition and mechanical properties per the specified standard (GB/T, EN 10219, or ASTM A53). Third-party inspection through SGS or BV is arranged on request, with full photographic documentation provided before shipment.
Q: Can you produce non-standard dimensions and what is the MOQ?
A: We produce custom non-standard sizes beyond our standard 15×15mm to 800×800mm range, including special wall thicknesses and non-stock lengths. MOQ is negotiable based on specification complexity and order volume.
Q: What is the difference between hot-dip galvanized and electro-galvanized surface treatment?
A: Hot-dip galvanizing applies a thicker zinc coating (typically 45–85 microns) suitable for outdoor and corrosive environments, providing longer corrosion protection. Electro-galvanizing produces a thinner, more uniform coating (typically 5–25 microns) suited for indoor applications where appearance matters. We recommend hot-dip for scaffolding and outdoor structural frames, electro-galvanized for indoor machinery and architectural applications.
Q: How do you prevent bending and surface damage during container loading?
A: Our loading team uses custom steel cradles, timber dunnage, and edge protectors to secure tubes during transit. Smaller sections are nested inside larger profiles to maximize container space while preventing movement. Each container is photographed before sealing, with loading plans provided for your records.
Get Your Carbon Steel ERW Square Rectangular Steel Tube Quote Today
Submit your specifications to admin@sdxjypipe.com or WhatsApp +86 188 5315 7756 for pricing, mill test certificate confirmation, and delivery scheduling within 12 hours.
