Description
Factory-Direct Welded Stainless Tubes — 304 and 201 grades produced in-house with nine surface finishes, shipped with full mill test certificates to 50+ countries.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | 304/201 Stainless Steel Welded Square Steel Tube |
| Product Type | Welded Square Steel Tube (Stainless Steel) |
| Steel Grade | 304, 201 |
| Standard | AISI, ASTM, BS, DIN, GB, JIS, EN |
| Section Shape | Square |
| Size Range | 25×25 mm – 200×200 mm |
| Wall Thickness | 1–10 mm |
| Length | 1000–6000 mm |
| Technique | Cold Rolled / Hot Rolled, Welded (Seamless-ERW) |
| Surface Treatment | BA / 2B / NO.1 / NO.3 / NO.4 / 8K / HL / 2D / 1D |
| Tolerance | ±1% |
| Ends | Plain / Custom |
| Application | Construction / Building / Industry / Structural framing / Architectural facades / Machinery |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Architectural Facades | Glass curtain wall framing, decorative column cladding, exposed structural grids with 8K or HL finish |
| Industrial Construction | Corrosion-resistant structural frames in chemical plants, food processing facilities, coastal infrastructure |
| Machinery Manufacturing | Precision equipment frames, conveyor supports, automated system structures requiring ±1% tolerance |
| Building & Infrastructure | Interior structural columns, handrail systems, mezzanine framing with NO.4 or BA surface |
Why Surface Finish Selection Determines Project Acceptance on Stainless Facade Work
The wrong finish grade triggers visual rejection before structural inspection even begins.
Architectural facade contractors specify 8K mirror or HL brushed finishes for exposed stainless framing, but mills often deliver NO.4 when 8K is ordered — the difference is visible under site lighting and fails aesthetic approval [NEED_CITE: stainless steel surface finish classification per ASTM A480]. On a Lagos curtain wall project I supervised, we received 304 square tubes labeled “mill finish” that showed weld seam discoloration within weeks of coastal installation. The crew spent three weeks re-sorting and re-welding on-site while the facade schedule collapsed. That’s when I learned surface finish consistency matters as much as grade certification.
Matching Finish Grades to Environmental Exposure and Design Intent
For coastal or high-humidity environments, 304 grade with BA or 2B finish provides adequate corrosion resistance without the cost premium of mirror polish. When the 304 stainless steel welded square tube supplier delivers consistent surface treatment across all batches, facade contractors avoid patchy weathering patterns that emerge after six months of UV exposure. Our cold rolling process maintains ±1% dimensional tolerance while achieving uniform grain direction on HL finishes — critical when adjacent tubes must reflect light identically across a 40-meter curtain wall span.
Structural Compliance and Certification Requirements for Export Markets
European facade projects require CE marking per EN 10219 for cold-formed welded hollow sections, while North American structural applications reference ASTM A554 for mechanical tubing [NEED_CITE: EN 10219 cold-formed structural hollow sections certification requirements]. The 304 stainless steel welded square tube supplier must provide mill test certificates documenting chemical composition (Cr, Ni, C content) and mechanical properties per the specified standard. For custom non-standard sizes outside 25×25 to 200×200 mm range, third-party inspection from SGS or BV confirms dimensional compliance before container loading.
Understanding 304 vs 201 Grade Selection for Cost-Performance Balance
304 stainless steel contains 18% chromium and 8% nickel, providing superior corrosion resistance suitable for outdoor architectural applications and chemical environments. 201 grade substitutes manganese and nitrogen for partial nickel content, reducing material cost while maintaining acceptable strength for indoor structural framing and dry environments. The welded ERW process joins rolled strip edges under pressure, creating a continuous weld seam that requires proper pickling and passivation to restore corrosion resistance at the joint [NEED_CITE: stainless steel weld quality and corrosion resistance relationship].
Cold rolled finishes (BA, 2B) achieve smoother surfaces with tighter thickness tolerance compared to hot rolled (NO.1, 2D), making them preferred for visible architectural applications. Wall thickness from 1–10 mm covers both lightweight decorative framing and heavy structural load-bearing members. Custom cutting to exact project lengths eliminates on-site welding for standard connections, reducing labor costs and maintaining surface integrity.
Hidden Costs of Incorrect Grade Specification and Certification Gaps
Ordering 201 grade for coastal facade work accelerates corrosion at weld seams within months, triggering expensive replacement cycles. Missing CE documentation blocks EU customs clearance, stranding containers at port while projects face delay penalties. Welded tubes with improper post-weld treatment show intergranular corrosion along seam lines, compromising structural integrity under load [NEED_CITE: stainless steel sensitization and intergranular corrosion mechanisms]. The 304 stainless steel welded square tube supplier must verify heat number traceability from raw coil to finished tube, ensuring chemical composition matches certified specifications.
Procurement Advantages from Integrated Production and Certification Capability
Our in-house physical and chemical laboratory tests every batch for dimensional accuracy, surface quality, and material composition before shipment. With 2,800+ specifications in production inventory, we consolidate multiple size requirements into single container loads, reducing freight costs and simplifying customs documentation. The 41 invention patents include proprietary sharp-corner rectangular tube technology — when your project requires right-angle joints for glass curtain wall framing, we deliver precise 90-degree corners without the rounded radii typical of standard welded tubes.
Full international certifications (ISO 9001:2015, Lloyd’s CE per EN 10210/10219, Singapore FPC) ensure smooth customs clearance across 50+ export destinations. Professional container loading with anti-damage protection preserves surface finishes during ocean transit, while custom marking with heat numbers and grade identification supports site traceability requirements.
Documentation & Compliance
- Mill test certificate documenting 304 chemical composition (18% Cr, 8% Ni) and 201 mechanical properties per ASTM A554 or EN 10219
- CE certificate per EN 10219 for cold-formed welded stainless steel hollow sections, required for EU market access
- ISO 9001:2015 quality management certificate covering production process and inspection procedures
- SGS or BV third-party inspection report verifying dimensional tolerance (±1%) and surface finish quality before shipment
- Material traceability by heat number from stainless steel coil to finished welded square tube
- Customs documents including packing list, bill of lading, and certificate of origin for import clearance
Packaging, Loading & Delivery
- Stainless steel square tubes bundled with steel straps and edge protectors to preserve BA/2B/8K surface finishes during handling
- Surface protection with plastic film wrapping for mirror polish (8K) and brushed (HL) finishes to prevent scratching
- Container loading optimization for 6-meter lengths maximizes 20ft GP capacity while maintaining weight distribution
- Custom cutting to 1000–6000 mm project-specific lengths reduces on-site waste and welding requirements
- Heat number and grade (304/201) marked on each tube end for site identification and traceability
- FOB/CIF/DDP shipping terms with professional export documentation for 50+ country destinations
Streamlining Specification Review and Certification Confirmation
Submit your project requirements including steel grade (304 or 201), dimensions (25×25 to 200×200 mm), wall thickness (1–10 mm), surface finish preference, and destination port. We respond within 12 hours with detailed quotation including unit price, MOQ (1 Ton), production lead time, and shipping terms. Request mill test certificates and third-party inspection reports before contract signing to verify material compliance. Confirm custom sizes, cutting requirements, and certification needs (CE/EN for EU, ASTM for North America) to ensure smooth project execution.
Frequently Asked Questions
Q: What is the difference between 304 and 201 stainless steel for square tube applications?
A: 304 contains higher nickel content (8%) providing superior corrosion resistance for outdoor and coastal environments, while 201 uses manganese substitution for cost savings in indoor or dry applications. Both grades are available in welded square tube format with identical dimensional ranges.
Q: Which surface finish is suitable for architectural facade applications?
A: 8K mirror polish and HL brushed finishes provide aesthetic appeal for exposed curtain wall framing, while BA and 2B offer smooth surfaces for interior structural applications. NO.4 satin finish balances cost and appearance for moderate-exposure environments.
Q: Can you produce non-standard sizes outside the 25×25 to 200×200 mm range?
A: Yes, custom non-standard sizes are available with low MOQ policy. Our 2,800+ specification inventory and flexible production lines accommodate special requirements for architectural and industrial projects.
Q: What certifications are provided for EU market export?
A: We supply CE marking per EN 10219 for cold-formed welded hollow sections, along with mill test certificates, ISO 9001:2015 quality certification, and optional SGS/BV third-party inspection reports for customs clearance.
Q: How do you ensure surface finish quality during shipping?
A: Mirror polish (8K) and brushed (HL) finishes receive plastic film wrapping, while all tubes are bundled with edge protectors. Professional container loading with anti-damage measures preserves surface integrity during ocean transit.
Request Your 304/201 Stainless Steel Square Tube Quotation
Send specifications including grade, dimensions, surface finish, quantity, and destination to receive pricing and mill test certificates within 12 hours.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
