Description
Factory-direct galvanized welded square steel tube — 2,800+ specifications with wall thickness up to 40mm produced on three in-house lines, shipped to 50+ countries with full CE and ISO documentation.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Welded Square and Rectangular Steel Tube |
| Product Type | Welded Square and Rectangular Steel Tube |
| Steel Grade | Carbon Steel (Hot Rolled Hollow Carbon Pipe); equivalent to Q195–Q235 range |
| Standard | AISI (intended ASTM A500 / EN 10219 — verify with mill) |
| Section Shape | Square / Rectangular / Round |
| Size Range | Custom non-standard sizes available |
| Wall Thickness | 0.9 mm |
| Length | 6 m / 6.4 m / 12 m |
| Technique | Welded (ERW) |
| Surface Treatment | Galvanized Coating / Hot Rolled |
| Tolerance | ±1% |
| Ends | Plain / Beveled upon request |
| Application | Construction / Fluid Pipe / Boiler Pipe / Drill Pipe / Hydraulic Pipe / Gas Pipe / Oil Pipe / Chemical Fertilizer Pipe / Structure Pipe |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding systems, bridge support structures |
| Architectural Facades | Glass curtain wall framing, sharp-corner rectangular tubes for aesthetic steel facades |
| Machinery Manufacturing | Industrial equipment structural supports, conveyor frame assemblies |
| Steel Structure Fabrication | Raw material for welded connections, column and beam fabrication |
| Energy & Utilities | Solar mounting structures, wind turbine support towers |
What Rounded Corners Cost on a Glass Curtain Wall Order
Standard rectangular tubes with R≥2t corners create visible gaps at mitered joints, forcing facade contractors to grind, fill, and repaint — adding 15–20% labor cost per linear meter.
When I supervised facade installations in São Paulo, a high-rise project specified sharp-corner rectangular tubes for the curtain wall grid. The supplier delivered standard ERW tubes with rounded corners. Every intersection showed uneven gaps. The entire container was rejected at site. The contractor had to reorder from a mill with patented sharp-corner technology — three weeks late, 40% over budget. [NEED_CITE: architectural facade tolerance requirements for sharp-corner hollow sections]
Beyond corner quality, buyers face specification gaps: off-standard sizes and heavy-wall sections are difficult to source from most mills. Missing CE marks or incorrect EN standard references block EU customs clearance. And improper container loading causes bending and surface damage that only appears after unloading.
How Galvanized ERW Tubes Match Structural Frame Requirements
Galvanized welded square steel tube delivers corrosion resistance for outdoor and humid environments while maintaining ±1% dimensional tolerance for precision fit-up in steel frames. The ERW welding process ensures consistent wall thickness across the 6 m and 12 m lengths, critical for load-bearing columns and beam connections. Full processing services — cutting, punching, bending, welding — allow fabricators to receive ready-to-assemble components. Theoretical weight invoicing provides transparent cost control without hidden thickness deviations.
Engineering Compliance and Certification Requirements
Structural hollow sections must conform to EN 1993-1-1 for European projects or AISC 360 for North American construction, requiring documented yield strength and chemical composition. [NEED_CITE: EN 10219 cold-formed welded structural hollow sections certification] Galvanized surface treatment extends service life in corrosive environments but requires proper edge protection during handling to preserve the zinc coating. Steel grade selection — Q195–Q235 equivalent to S235JR — determines load capacity and weldability. CE certification under EN 10210/EN 10219 is mandatory for EU market entry, while ASTM A500 compliance applies to North American projects. Custom lengths of 6 m, 6.4 m, and 12 m reduce on-site cutting waste and accelerate assembly. [NEED_CITE: steel grade equivalence between GB Q-series and EN S-series standards]
Understanding ERW Welding and Galvanized Surface Treatment
ERW (Electric Resistance Welding) forms the tube by rolling steel strip into shape and welding the seam through electrical resistance heat. This process suits square and rectangular profiles with consistent wall thickness, offering lower cost than seamless tubes for structural applications. Galvanized coating applies a zinc layer through hot-dip or electro-galvanizing, providing sacrificial corrosion protection that extends service life in outdoor, coastal, or high-humidity environments. The ±1% tolerance ensures dimensional accuracy for precision connections, while theoretical weight invoicing based on standard density prevents overpayment from negative thickness deviations. For architectural applications, sharp-corner rectangular tubes with R≤0.5t corners deliver clean mitered joints without grinding or filling.
Hidden Costs of Incorrect Material Selection
Ordering standard rounded-corner tubes for architectural facades creates visible joint gaps that require expensive remediation. Material certificates missing heat number traceability fail third-party inspection, delaying project handover. Negative wall thickness beyond tolerance limits reduces load capacity, triggering structural engineer rejection. Missing CE marks or incorrect EN standard references cause customs holds at EU ports, incurring demurrage charges. [NEED_CITE: structural hollow section dimensional tolerance requirements per EN 10219]
Why Source Galvanized Welded Square Steel Tube from SD XJY Pipe
Three production lines covering 2,800+ specifications with wall thickness up to 40mm eliminate multi-supplier coordination. In-house physical and chemical laboratories issue Mill Test Certificates per EN 10204 3.1, documenting chemical composition and mechanical properties for every heat. 41 invention patents include China’s first sharp-corner rectangular tube technology, filling the gap for architectural applications requiring clean corner profiles. Full international certifications — ISO 9001:2015, Lloyd’s CE (EN 10210/10219), Singapore FPC, SGS/BV verification — ensure customs clearance in regulated markets. Custom non-standard sizes with low MOQ of 1 Ton accommodate specialized engineering requirements. Professional container loading with anti-damage measures prevents bending and surface scratches during ocean freight.
Documentation & Compliance
- Mill Test Certificate documenting Q195–Q235 equivalent chemical composition and yield strength per EN 10219
- CE certificate under EN 10210/EN 10219 for cold-formed welded structural hollow sections
- ISO 9001:2015 quality management system certificate covering production and testing processes
- SGS or BV third-party inspection report verifying dimensional tolerance and surface coating thickness
- Material traceability by heat number linking each tube to production batch and test results
- Customs documents including packing list, bill of lading, and certificate of origin for destination clearance
Packaging, Loading & Delivery
- Galvanized tubes bundled with steel strips and edge protectors to preserve zinc coating during ocean transit
- Surface protection maintained through proper stacking with wooden separators preventing coating abrasion
- Container loading optimized for 6 m and 12 m lengths with anti-bending supports at critical stress points
- Custom cutting to project-specific lengths reduces on-site waste and accelerates installation
- Heat number and steel grade marked on each tube for site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional loading supervision for export orders
Request Quotation with Mill Test Certificate
Submit your specifications — section shape, dimensions, steel grade, surface treatment, quantity, and destination port — to receive detailed pricing with unit cost per ton or piece, production lead time, and shipping terms. Request Mill Test Certificate samples and third-party inspection options before contract signing. Confirm CE certification requirements for EU projects or ASTM compliance for North American delivery. Verify container loading plans and delivery schedules for time-sensitive construction timelines.
Frequently Asked Questions
Q: What is the difference between galvanized and hot-rolled surface treatment for square tubes?
A: Galvanized coating provides zinc-layer corrosion protection suitable for outdoor and humid environments, extending service life without maintenance. Hot-rolled surface offers bare steel finish for indoor applications or projects requiring field painting. Selection depends on environmental exposure and project specifications.
Q: How do you ensure dimensional tolerance and corner quality for architectural applications?
A: ERW welding process maintains ±1% tolerance across all lengths. Patented sharp-corner technology produces rectangular tubes with R≤0.5t corners for clean mitered joints in curtain wall framing. In-house laboratory performs dimensional inspection before shipment.
Q: Can you produce non-standard sizes and what is the MOQ for custom orders?
A: Custom non-standard sizes are available across 2,800+ specifications with wall thickness up to 40mm. MOQ is 1 Ton for both standard and custom orders. Production lead time for non-standard sizes is typically 15–25 days.
Q: What certifications do you provide for EU and international market compliance?
A: Full certification package includes CE mark under EN 10210/EN 10219 for EU markets, ISO 9001:2015 quality management, Singapore FPC, and SGS/BV third-party verification. Mill Test Certificates per EN 10204 3.1 accompany every shipment.
Q: How do you handle container loading to prevent damage during ocean freight?
A: Professional loading with anti-bending supports, wooden separators, and edge protectors prevents surface damage and deformation. Loading plans optimize container space for 6 m and 12 m lengths. Third-party inspection available to verify loading quality before container sealing.
Get Your Galvanized Welded Square Steel Tube Quote with Full Certification
Submit specifications — section shape, dimensions, steel grade, quantity, destination port — to receive pricing, Mill Test Certificate samples, and production schedule within 12 hours.
Contact SD XJY Pipe
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
