Description
Factory-Direct Stainless Tubes, No Middlemen — Every 304 stainless steel square rectangular tube ships from our own ERW mill with in-house chemical verification, cutting out trader markups on your architectural orders.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | 304 Stainless Steel Square Rectangular Tube |
| Product Type | Welded Stainless Steel Square / Rectangular Tube |
| Steel Grade | 201, 304, 316, 316L, 316Ti, 430, 439 |
| Standard | GB |
| Section Shape | Square / Rectangular |
| Size Range | 10mm × 20mm – 100mm × 200mm |
| Wall Thickness | 0.8mm – 5.0mm |
| Length | 1m / 2m / 3m / 6m (custom cutting available) |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | BA (Bright Annealed) / Mirror Polish / Brushed / Satin / Matt |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Bending, Welding, Decoiling, Punching, Cutting |
| Application | Architectural decorations / Handrails / Balustrades / Window & door frames / Kitchen equipment / Display racks / Furniture frames / Railings / Structural framing |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Architectural Decoration | Stair handrails, balcony balustrades, window and door frames, decorative railings |
| Interior & Furniture | Display racks, kitchen equipment frames, commercial furniture structures |
| Light Structural Framing | System integrator conveyor frames, equipment enclosures, mezzanine supports |
Why BA Surface Finish Determines Whether Your Handrail Arrives Sellable
Bright annealed 304 stainless square tubes arrive with a reflective, oxide-free surface that skips post-arrival polishing entirely.
I once watched a container of 304 stainless architectural tubes get rejected at a West African port because the supplier skipped inter-layer separators during loading. Every BA-finished face was cross-scratched. The buyer paid for the tubes twice. When you source a 304 stainless steel square rectangular tube supplier who understands surface protection, the difference between a sellable handrail and scrap metal comes down to how each piece is padded, separated, and strapped inside the container — not just the mill finish itself. Inconsistent surface treatment and unprotected transit remain among the most common complaints from architectural steel buyers across developing markets [NEED_CITE: stainless steel surface protection during ocean freight].
Matching Finish and Grade to Architectural Environments
A 304 stainless steel square rectangular tube in BA finish handles interior handrails and display racks where chloride exposure stays low. Move to coastal balustrades or outdoor railings in humid climates, and 316L becomes the baseline — its molybdenum content resists pitting that 304 cannot. For projects spanning both zones, sourcing multiple grades from a single 304 stainless steel square rectangular tube supplier avoids split shipments and mismatched lead times. Our ERW lines run 201 through 439 in square and rectangular sections from 10×20mm to 100×200mm, so a single purchase order covers interior furniture frames and exterior structural railings without coordinating separate mills.
Engineering Compliance and Certification for Stainless Architectural Tubes
Architectural stainless tubes rarely carry structural load calculations the way S355 carbon sections do, yet customs authorities in the EU and Middle East still demand traceable material certification for stainless imports [NEED_CITE: stainless steel hollow section import documentation requirements]. GB-standard 304 and 316L tubes ship with mill test certificates documenting chemical composition per heat number, satisfying most port clearance needs. For projects specifying European or American equivalents, third-party inspection through SGS or BV bridges the gap between GB chemistry and EN/ASTM expectations. Wall thickness tolerance of ±1% across the 0.8mm–5.0mm range keeps theoretical weight calculations reliable for structural framing and system integrator applications.
Steel Grade Selection and ERW Welding for Stainless Square Tubes
The 201 grade trades nickel content for manganese and nitrogen, lowering cost for dry indoor applications like display racks and furniture frames where corrosion risk is minimal. 304 remains the architectural workhorse — sufficient for most interior handrails, kitchen equipment, and window frames in non-coastal environments. 316L and 316Ti add molybdenum for chloride resistance, essential for coastal balustrades and chemical-adjacent kitchen installations. The 430 and 439 ferritic grades offer magnetic properties and lower cost where formability matters more than deep-draw corrosion performance. ERW welding produces a clean, consistent weld seam suited to the 0.8mm–5.0mm wall range, avoiding the porosity risks that can appear in thicker seamless processes at these small cross-sections. The ±1% dimensional tolerance ensures that when a contractor bends a 20×20mm handrail section around a stair curve, the inner radius stays predictable.
The Hidden Cost of Unverified Stainless Grades on Architectural Projects
Shipping a container labeled “304” that tests as 201 at destination means every handrail section fails salt-spray expectations and the entire installation gets ripped out. Certification gaps — missing heat numbers, absent MTCs, no third-party verification — trigger customs holds that delay projects by weeks and incur demurrage charges that dwarf the tube cost itself [NEED_CITE: customs documentation requirements for stainless steel imports]. Negative tolerance abuse on 0.8mm wall tubes specified at 1.0mm reduces load capacity on structural framing and fails engineering inspection. The cost of re-procurement, re-shipping, and project delay always exceeds the price difference between a verified 304 stainless steel square rectangular tube supplier and an unverified one.
Procurement Confidence from Mill to Port
Every 304 stainless steel square rectangular tube rolls through our own ERW lines — no trading company markup, no blended heat sourcing. Our in-house physical and chemical laboratory verifies composition per heat number before any tube leaves the mill, and original MTCs travel with every shipment. With over 2,800 specifications across square, rectangular, round, and section steel, a single order covering handrails, balustrades, and furniture frames ships from one factory. We hold ISO 9001:2015, Lloyd’s Register EU CE, Singapore FPC, and SGS/BV verification — documents that clear customs in the EU, Middle East, and Southeast Asia without supplementary testing. Custom non-standard sizes, cutting to exact length, bending, and laser logo engraving all happen in-house, eliminating the coordination risk of splitting orders across multiple processors. Professional loading plans optimize container space for mixed-size architectural orders, and door-to-door logistics reach 50+ countries.
Documentation & Compliance
- Mill Test Certificate documenting 304 and 316L chemical composition (Cr, Ni, Mo, C content) and mechanical properties per GB standard, traceable by heat number
- CE certificate covering EN 10219 cold-formed structural hollow sections for EU project compliance
- ISO 9001:2015 quality management system certificate covering full production and inspection workflow
- SGS or BV third-party inspection report available per shipment for independent grade and dimension verification
- Material traceability report linking each bundle to its heat number, chemical analysis, and production date
- Full customs document package including packing list, Bill of Lading, and Certificate of Origin for destination port clearance
Packaging, Loading & Delivery
- BA-finished 304 stainless tubes bundled with soft edge protectors and inter-layer separators to prevent surface scratching during ocean transit
- Mirror-polish and brushed finish tubes individually wrapped in protective film before bundling, preserving surface integrity through container loading and unloading
- Custom-cut lengths (1m/2m/3m/6m) bundled separately by size with steel strip ties and labeled with heat number, steel grade, and dimensions
- Mixed-size architectural orders loaded with professional stowage plans optimizing 20ft and 40ft container space for handrail sections, balustrade tubes, and furniture frame profiles
- FOB, CIF, and DDP shipping terms available with real-time tracking to ports across the EU, Middle East, Southeast Asia, and 50+ countries
- Each bundle marked with steel grade (201/304/316L), section dimensions, wall thickness, and heat number for on-site identification and inspection
Start Your Stainless Tube Procurement With Verified Specifications
Submit your section dimensions, steel grade, surface finish, quantity, and destination port — we respond within 12 hours with unit pricing, production lead time, applicable certifications, and shipping options. For non-standard sizes or custom processing including bending, cutting, and punching, share your drawings and we return a fabrication proposal with the same mill test documentation.
Request a Quote With Mill Test Certificate
Send your specifications to admin@sdxjysteel.com or WhatsApp +86 188 5315 7756 with section size, steel grade, finish, quantity, and destination port.
Frequently Asked Questions
Q: What is the difference between 201, 304, and 316L stainless steel for square tubes?
A: 201 uses manganese and nitrogen to replace部分 nickel, offering lower cost for dry indoor applications like display racks. 304 provides reliable corrosion resistance for interior handrails, kitchen equipment, and window frames. 316L adds molybdenum for chloride resistance, required for coastal balustrades and humid outdoor environments.
Q: Can you provide custom non-standard sizes and what is the MOQ?
A: We produce custom non-standard square and rectangular sizes beyond the standard 10×20mm to 100×200mm range through our dedicated ERW lines. MOQ depends on the specific non-standard profile — contact us with your drawing for exact minimum quantity and lead time.
Q: What surface finishes are available and how do they affect corrosion resistance?
A: We offer BA (Bright Annealed), Mirror Polish, Brushed, Satin, and Matt finishes. The base steel grade determines corrosion resistance — BA and mirror finishes on 304 perform identively in salt-spray terms; the finish choice is aesthetic. For coastal or chemical environments, upgrade the grade to 316L regardless of finish.
Q: Do you provide Mill Test Certificates and third-party inspection reports for customs clearance?
A: Every shipment includes an original Mill Test Certificate documenting chemical composition and mechanical properties per heat number. SGS or BV third-party inspection reports are available upon request and commonly required for EU, Middle East, and Southeast Asian customs clearance.
Q: What is the production lead time and do you support FOB/CIF/DDP shipping?
A: Standard sizes in 201/304/316L typically ship within typical production lead times from order confirmation. Custom sizes and processing (bending, cutting, punching) add to the timeline. We support FOB, CIF, and DDP terms with door-to-door logistics to 50+ countries.
