Description
Factory-Direct Welded SHS — 2,800+ specifications produced on dedicated ERW lines with in-house lab verification per ASTM A500.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Carbon Steel Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube / Square Hollow Structural Section (SHS) |
| Steel Grade | Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Square |
| Size Range | 19mm × 19mm – 800mm × 800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | ERW (Welded) |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction structures / Building frames / Curtain wall systems / Support tubes / Structural frameworks |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| EPC Contractors | Steel structure frames for industrial plants and warehouse buildings |
| Construction Companies | High-rise building columns, curtain wall mullions, and infrastructure support brackets |
| Machinery Manufacturers | Equipment base frames, conveyor support structures, and automated system chassis |
| System Integrators | Conveyor gantry frames, automation line supports, and modular structural assemblies |
What Negative Tolerance Exceedance Costs on a Structural Frame Order
A mill certificate that reads 3.00mm means nothing when the caliper shows 2.55mm at the destination port.
Global buyers ordering welded square tubes for structural frames routinely encounter material that passes factory inspection but fails third-party measurement on arrival. The root cause is not always deliberate — production line drift, inconsistent roll pressure, and inadequate in-process gauging allow wall thickness to slip below the ±1% tolerance band specified in ASTM A500. When a container of 60×60 welded square tubes arrives at Jebel Ali with actual wall thickness measuring 2.55mm against a nominal 3.00mm, the entire shipment sits stuck for weeks while the buyer negotiates re-inspection, partial rejection, or costly air-freight replacement. [NEED_CITE: ASTM A500 tolerance requirements for cold-formed welded structural tubing] Specification gaps compound the problem: standard catalogs rarely cover non-standard sizes, and custom orders from fragmented suppliers face long lead times with no guarantee of dimensional consistency across batches.
How Wall-Thickness Consistency Matches Structural Frame Requirements
Structural frames for high-rise buildings and industrial plants demand that every column and beam carry load as calculated — no margin exists for wall thickness that drifts below design specification. An ASTM A500 welded square steel tube produced on dedicated ERW lines with in-house physical and chemical laboratory testing maintains the ±1% tolerance that structural engineers specify. When a curtain wall system requires 100×100×4mm S355 tubes for mullion support, each piece must deliver the exact section modulus the engineer calculated; a 0.4mm shortfall in wall thickness reduces load capacity and triggers rejection during site inspection.
Engineering Compliance and Surface Treatment Selection
Structural steel for EU markets must conform to EN 10219 cold-formed welded hollow sections, while North American projects specify ASTM A500 Grade B or C — the steel grade and standard determine whether customs clearance proceeds smoothly or the container sits at port awaiting supplementary documentation. [NEED_CITE: EN 10219 cold-formed structural hollow section compliance requirements] Corrosion environment dictates surface treatment: hot-dip galvanized finish suits coastal construction and outdoor infrastructure where moisture and salt accelerate corrosion, while black painting or varnish suffices for indoor structural frames in controlled environments. Bare tubes ship at lowest cost but require immediate on-site priming before exposure. Wall thickness tolerance directly affects theoretical weight calculations used for invoicing and structural load analysis — buyers specifying ASTM A500 welded square steel tube must confirm whether the supplier invoices on actual weight or theoretical weight, as negative tolerance beyond standard creates hidden cost exposure.
Steel Grade Selection and ERW Welding Process
The steel grades offered — Gr.B, S235, S275, S355, and STK400 — span three international standard systems: ASTM (American), EN (European), and JIS (Japanese). S235, S275, and S355 follow an ascending yield strength classification under EN 10025, where each grade increment provides higher load-bearing capacity for demanding structural applications. Gr.B under ASTM A500 corresponds roughly to S235 in minimum yield strength, while STK400 under JIS G3466 serves general structural purposes in Japanese-specification projects. ERW (Electric Resistance Welded) production forms the square section from steel coil through continuous cold-forming and high-frequency welding — this process delivers tight dimensional tolerance, smooth weld seam, and cost efficiency for sizes from 19×19mm to 800×800mm. The weld seam in ERW welded square steel tube runs along one flat face, distinguishing it from seamless pipe and making it suitable for structural rather than high-pressure fluid applications. Surface treatment options — galvanized, black painted, varnish, or bare — address different corrosion environments without altering the base steel grade properties.
Hidden Costs When Certification and Material Traceability Fail
Ordering welded square tubes without verified mill test certificates creates a cascade of downstream costs: customs authorities in EU and Middle East markets routinely hold shipments lacking CE marking or EN 10219 compliance documentation, forcing buyers to pay demurrage while scrambling for retroactive certification. [NEED_CITE: customs documentation requirements for structural steel imports in EU and GCC countries] Material traceability gaps — missing heat numbers, unverified steel grade, or certificates from non-accredited laboratories — mean the structural engineer cannot sign off on the frame, triggering costly re-inspection or complete material replacement. Negative tolerance that exceeds ASTM A500 limits reduces section modulus below design values, creating structural safety concerns that surface only during load testing or, worse, after installation.
Procurement Confidence Through Verified Production Capability
Every ASTM A500 welded square steel tube shipped from our facility passes through an in-house physical and chemical laboratory that tests incoming coil material, monitors weld seam integrity during production, and verifies final dimensions before bundling. Original mill test certificates documenting chemical composition and mechanical properties accompany each shipment, with heat number traceability from coil to finished tube. Third-party inspection by SGS or BV is available before loading — we welcome buyer-nominated inspectors to verify dimensions, surface quality, and documentation at our facility. Our dedicated ERW production lines cover 2,800+ specifications from 19×19mm to 800×800mm with wall thickness up to 30mm, eliminating the need to source small sections from one supplier and large sections from another. Factory-direct pricing means no trading company margin sits between your project budget and the mill output. Custom non-standard sizes beyond catalog specifications are available with typical production lead times, and professional loading plans optimize container utilization for mixed-size orders destined for 50+ countries.
Documentation & Compliance
- Mill test certificate documenting Gr.B, S235, S275, S355, or STK400 chemical composition and mechanical properties per ASTM A500 / EN 10219 / GB/T 3091
- CE certificate confirming EN 10210 hot-formed or EN 10219 cold-formed structural hollow section compliance for EU market customs clearance
- ISO 9001:2015 quality management system certificate covering the full production process from coil incoming inspection to final dimensional verification
- SGS or BV third-party inspection report verifying wall thickness, dimensions, surface quality, and weld seam integrity before shipment
- Material traceability documentation linking each tube bundle to specific heat numbers and coil batch records
- Complete customs document package including packing list, bill of lading, and certificate of origin for destination port clearance
Packaging, Loading & Delivery
- Galvanized ASTM A500 welded square steel tubes bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit
- Black painted or varnished tubes wrapped with waterproof paper and secured in seaworthy bundles suitable for 5.8m, 6m, 11.8m, or 12m random or fixed lengths
- Container loading plans optimized for mixed-size orders combining small sections (19×19mm to 100×100mm) with large sections (up to 800×800mm) to maximize 20ft and 40ft container utilization
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability verification during installation
- FOB, CIF, and DDP shipping terms available with professional port coordination and door-to-door logistics to 50+ countries across EU, North America, Middle East, Southeast Asia, and South America
- Custom cutting to specific project lengths available before packaging, reducing on-site waste and secondary processing costs
Start Your ASTM A500 Welded Square Steel Tube Inquiry
Submit your specifications — section size, wall thickness, steel grade, quantity, surface treatment preference, and destination port — via email or WhatsApp to receive a detailed quotation including unit price, delivery timeline, applicable certifications, and mill test certificate confirmation within 12 hours. Non-standard sizes and custom length requirements receive engineering review for feasibility and production scheduling.
Request Quotation and Mill Test Certificate
Send your ASTM A500 welded square steel tube inquiry with full specifications to receive pricing, certification confirmation, and delivery schedule.
Email: admin@sdxjysteel.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Tel: +86 531 8573 6315
Frequently Asked Questions
Q: Can you provide ASTM A500 welded square steel tubes in both small sizes like 19×19mm and large sizes like 800×800mm from a single order?
A: Yes, our dedicated ERW production lines cover the full range from 19mm × 19mm to 800mm × 800mm with wall thickness from 1mm to 30mm, allowing mixed-size orders from one supplier with consistent quality control and unified documentation.
Q: What surface treatment options are available for ASTM A500 welded square steel tubes, and how do I choose?
A: We offer hot-dip galvanized for outdoor and corrosive environments, black painting or varnish for indoor structural applications, and bare finish for projects requiring on-site coating — the choice depends on your installation environment and corrosion exposure requirements.
Q: Do you provide third-party inspection before shipment for ASTM A500 welded square steel tubes?
A: Yes, SGS and BV third-party inspections are available upon request to verify wall thickness, dimensions, surface quality, and weld seam integrity before container loading, with full inspection reports provided to the buyer.
Q: Can you produce non-standard sizes beyond your catalog specifications for ASTM A500 welded square steel tubes?
A: Custom non-standard sizes are available beyond our 2,800+ catalog specifications — submit your required dimensions for engineering review and production feasibility confirmation with typical lead times.
Q: What documentation do you provide for EU customs clearance when importing ASTM A500 welded square steel tubes?
A: We provide CE certification under EN 10219 for cold-formed structural hollow sections, mill test certificates with full material traceability, ISO 9001 quality certificates, and complete customs documents including packing list, bill of lading, and certificate of origin.
Secure Your ASTM A500 Welded Square Steel Tube Supply
Submit your project specifications — section size, wall thickness, steel grade, quantity, and destination — to receive a detailed quotation with mill test certificate confirmation and delivery timeline within 12 hours.
Email: admin@sdxjysteel.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
