Description
Factory-direct rectangular GI tubes — every batch shipped with original mill test certificates and SGS/BV inspection available before container sealing.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A500/A53 Rectangular GI Steel Pipe |
| Product Type | Rectangular Steel Tube (Welded) |
| Steel Grade | A53(A.B), Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Rectangular |
| Size Range | 15mm×20mm – 700mm×800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | Welded (ERW) / Seamless |
| Surface Treatment | Galvanized / Black Painting / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Bending, Cutting |
| Application | Construction Structure / Building / Curtain Wall / Support Tubes / Machinery / Steel Structures |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Building | Building frames, curtain wall support structures, roof trusses |
| Infrastructure | Scaffolding systems, bridge support tubes, highway signpost frames |
| Industrial & Machinery | Machinery frames, conveyor structures, equipment support bases |
| Steel Fabrication | EPC project structural modules, warehouse portal frames, mezzanine supports |
What Galvanized Coating Thickness Costs You at the Unloading Dock
A 40-micron zinc layer on a 60-micron spec doesn’t just fail a gauge test — it fails the entire project inspection.
I learned this the hard way flying to West Africa to sort out a rejected container. The mill certificate said the rectangular GI tubes passed, but the on-site coating gauge told a different story. Half the batch got turned away because the zinc thickness didn’t hold up to the actual environment they were building in. Since then, every ASTM A500 rectangular galvanized steel tube supplier we work with checks coating thickness three times before it leaves the yard — at the galvanizing line, at the finishing station, and again before loading. [NEED_CITE: hot-dip galvanized coating thickness requirements for structural steel]
Quality uncertainty in galvanized rectangular tubes usually hides in three places: inconsistent zinc distribution on inner corners, borderline coating thickness that passes mill testing but fails field verification, and surface defects that only show up after cutting or welding on site.
How Dimensional Range Matches Structural Frame Requirements
Rectangular GI tubes from 15mm×20mm up to 700mm×800mm cover everything from light gauge curtain wall purlins to heavy-duty portal frame columns. The ASTM A500 rectangular galvanized steel tube supplier maintains stock across this full range because structural engineers specify different section sizes for different load paths — and waiting six weeks for a non-standard size kills project timelines. Wall thickness from 1mm to 30mm means the same outer dimensions can serve either as lightweight bracing or primary load-bearing members, depending on the S235, S275, or S355 grade selected.
Engineering Compliance and Certification Requirements
Structural rectangular hollow sections used in load-bearing frames must comply with dimensional tolerances that affect connection fit-up and overall geometry. EN 10219 specifies cold-formed welded structural hollow sections, while ASTM A500 covers cold-formed welded and seamless carbon steel structural tubing in North American markets. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerances] For projects requiring CE marking, the rectangular tubes must carry FPC certification under EN 10210 or EN 10219, and every heat number must trace back to original mill test certificates showing chemical composition and mechanical properties. Galvanized coating adds another compliance layer — the zinc thickness must meet the corrosivity category of the installation environment per ISO 12944.
Steel Grade Selection and Welding Process Fundamentals
The S-series grades (S235, S275, S355) follow European standards where the number indicates minimum yield strength in MPa — S355 delivers roughly 50% higher yield than S235, making it the default choice for primary structural members in heavier frames. ASTM A53 Grade B and Gr.B serve similar roles in North American specifications. STK400, a Japanese standard structural carbon steel, appears frequently in Southeast Asian projects. ERW welded rectangular tubes suit most structural applications where internal pressure isn’t a factor, while seamless options handle higher stress concentrations at connection points. Hot-dip galvanizing provides sacrificial zinc protection that outperforms paint systems in corrosive environments, though the coating adds approximately 50–100 microns to overall dimensions — a factor that matters when tolerance stack-up affects bolt hole alignment.
Hidden Costs of Incorrect Material Procurement
Ordering the wrong steel grade or accepting borderline coating thickness creates costs that appear months after delivery. A rectangular tube specified as S355 but delivered as S275 won’t fail incoming inspection — both grades look identical, both carry mill certificates — but the structure may deflect beyond serviceability limits under design loads. [NEED_CITE: structural steel grade substitution risks in engineering projects] Missing or incomplete CE documentation stops containers at EU ports, turning a three-week delivery into a three-month delay with demurrage charges accumulating daily. Negative tolerance abuse — where wall thickness consistently sits at the lower limit — reduces theoretical weight savings but compromises buckling resistance in compression members.
Why Procurement Teams Choose Our Supply Chain
We operate three production lines running simultaneously with monthly capacity exceeding 20,000 tons, meaning urgent project schedules don’t require premium charges or compromised quality checks. Our in-house laboratory conducts three-stage inspection on every batch — incoming material verification, in-process dimensional checks, and final coating thickness measurement before release. The ASTM A500 rectangular galvanized steel tube supplier maintains original mill test certificates for every heat number, and third-party inspection through SGS or BV is available on request before container sealing. With over 2,800 specifications in ready stock, standard sizes ship within days rather than weeks, while custom orders for non-standard dimensions or specific steel grades follow typical production lead times. Professional export documentation handling covers customs clearance requirements for 50+ destination countries, and container loading optimization ensures maximum payload without damaging galvanized surfaces during ocean transit.
Documentation & Compliance
- Mill test certificate documenting S235/S275/S355 chemical composition and yield strength per EN 10219 or ASTM A500 Grade B mechanical properties per ASTM A53
- CE certificate under EN 10210 for hot-finished structural hollow sections or EN 10219 for cold-formed welded rectangular tubes, required for EU market access
- ISO 9001:2015 quality management certificate covering production processes and inspection procedures for galvanized rectangular steel tubes
- SGS or BV third-party inspection report verifying coating thickness, dimensional accuracy, and surface quality before shipment
- Material traceability documentation linking each bundle to specific heat numbers and original mill test certificates
- Complete customs document package including packing list, bill of lading, and certificate of origin for destination country clearance
Packaging, Loading & Delivery
- Galvanized rectangular tubes bundled with steel strips and edge protectors to preserve zinc coating integrity during ocean transit and handling
- Surface protection through passivation treatment or light oil coating on bare ends to prevent white rust formation on galvanized surfaces during storage
- Container loading optimization for 6m and 12m lengths maximizes payload per 20ft or 40ft container while preventing bundle shifting during transport
- Custom cutting service available for random length requirements, with cut ends deburred and protected against corrosion
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability verification
- FOB, CIF, and DDP shipping options with professional export documentation handling for destination country customs requirements
How to Initiate Bulk Procurement
Submit your rectangular tube specifications including outer dimensions, wall thickness, steel grade, total quantity, and destination port to receive competitive bulk pricing with volume discounts. We provide original mill test certificates and can arrange third-party inspection before shipment to verify coating thickness and dimensional compliance. For non-standard sizes or specific project requirements, our technical team reviews drawings and confirms feasibility with typical production lead times.
Frequently Asked Questions
Q: What is the difference between ASTM A500 and EN 10219 for rectangular steel tubes?
A: ASTM A500 is the North American standard for cold-formed welded and seamless carbon steel structural tubing, while EN 10219 covers cold-formed welded structural hollow sections of non-alloy and fine grain steels in European markets. Both standards specify dimensional tolerances and mechanical properties, but the testing methods and certification requirements differ. We supply rectangular tubes meeting either standard based on your project destination and engineering specifications.
Q: Can you provide mill test certificates for every batch?
A: Yes, every batch of ASTM A500 rectangular galvanized steel tube ships with original mill test certificates documenting chemical composition and mechanical properties for the specific heat number. These certificates provide full material traceability from steelmaking through final inspection. Third-party inspection through SGS or BV is also available upon request before container loading.
Q: What is the minimum order quantity for custom sizes?
A: Standard sizes from our ready stock of 2,800+ specifications have flexible MOQ starting from trial orders. For custom non-standard dimensions or specific steel grades not in regular stock, we accommodate both small trial orders and full-container bulk quantities. Production lead times for custom orders follow typical manufacturing schedules based on specification complexity.
Q: How do you ensure galvanized coating thickness meets project requirements?
A: Our galvanized rectangular tubes undergo three-stage coating thickness inspection — at the galvanizing line, during finishing, and before shipment. This process addresses the common issue where coating passes mill testing but fails on-site gauge verification. We can provide coating thickness measurements in the mill test certificate or arrange third-party verification to confirm compliance with your project’s corrosivity environment requirements.
Q: Do you handle export documentation and customs clearance?
A: Yes, our professional export team manages complete documentation packages including commercial invoice, packing list, bill of lading, certificate of origin, and all certificates required for destination country customs clearance. We have shipping experience to 50+ countries and can arrange FOB, CIF, or DDP terms based on your preference.
Request Your ASTM A500 Rectangular GI Tube Quote
Send your specifications — dimensions, wall thickness, steel grade, quantity, and destination port — to receive factory-direct pricing with mill test certificates and delivery schedule within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
