Description
Factory-direct ASTM A572 Gr 50 seamless square hollow section supply — every batch ships with original mill test certificates and supports SGS/BV third-party inspection before loading.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A572 Gr 50 Seamless Square Hollow Section |
| Product Type | Seamless Square and Rectangular Steel Tube / Hollow Section |
| Steel Grade | A572 Gr 50, Q195, Q235, Q345, Q355, S235JR, S275JR, S355JR, A500 |
| Standard | ASTM A572, ASTM A500, ASTM A213, DIN EN 10217-1, GB |
| Section Shape | Square / Rectangular |
| Size Range | 15×15 mm – 500×500 mm (Square) / 20×30 mm – 800×1200 mm (Rectangular) |
| Wall Thickness | 0.5 mm – 12 mm |
| Length | 5.8 m – 12 m (or according to customer requirements) |
| Technique | Seamless / Cold Drawn |
| Surface Treatment | Black, Bright, Galvanized (40–500 g/m² or customized), Painted, Slightly Oiled |
| Tolerance | ±1% – ±5% |
| Ends | Plain |
| Application | Steel structures / Construction frames / Machinery / Scaffolding / Furniture / Fluid transport / Drill pipe / Hydraulic pipe |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & EPC Projects | Load-bearing columns, building frames, portal frame structures |
| Machinery Manufacturing | Hydraulic cylinder barrels, drill pipe casings, equipment support frames |
| Infrastructure & Scaffolding | Scaffolding uprights, bridge support members, solar panel mounting structures |
| Industrial Fabrication | Conveyor system frames, crane boom sections, storage rack uprights |
What Negative Wall Tolerance Really Costs on a Structural Frame Order
A 0.3 mm tolerance deviation on a 6 mm wall square tube can shift theoretical weight by 5% — and trigger rejection at third-party inspection.
I have seen entire container loads of ASTM A572 Gr 50 seamless square hollow section held at destination ports because the actual wall thickness fell below the minimum allowed by the purchase specification. The mill test certificate looked perfect on paper, but when the buyer’s SGS inspector pulled random pieces from the bundle and measured with an ultrasonic gauge, three out of ten tubes failed. The root cause was not fraud — it was a supplier running at the extreme edge of negative tolerance to save raw material cost, then claiming “within standard range” when challenged. For a project buyer, this means two weeks of port demurrage, re-inspection fees, and the awkward conversation with the general contractor about whether the steel already welded into the frame can be accepted. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching ASTM A572 Gr 50 to Structural Load Requirements
The cold drawn seamless process behind this ASTM A572 Gr 50 seamless square hollow section produces uniform grain structure around the entire perimeter — critical when the tube serves as a compression member in a portal frame or a load-bearing column in a multi-story building. Unlike welded alternatives where the seam zone can become a weak point under cyclic loading, the seamless body distributes stress evenly across all four faces. For machinery frames requiring hydraulic pressure containment or drill pipe applications, this uniformity directly translates to predictable performance under internal and external pressure differentials. We maintain 2,800+ specifications in ready stock precisely because project procurement teams cannot wait 45 days for a non-standard 300×300×10 mm section when the foundation pouring schedule is already set.
Engineering Compliance and Certification Pathways
Structural engineers specifying ASTM A572 Gr 50 typically design to AISC or equivalent national codes that require documented yield strength and chemical composition traceability. When the same ASTM A572 Gr 50 seamless square hollow section ships to European markets, the buyer may need cross-referenced certification to EN 10210 or EN 10219 for customs clearance and local building authority approval. Our in-house metallurgical lab tests every heat number for tensile strength, yield point, elongation, and impact resistance — then issues an original mill test certificate that traces back to the specific billet batch. For clients importing into the EU, we hold Lloyd’s CE certification covering EN 10210 and EN 10219, which satisfies notified body requirements without requiring duplicate testing at destination. [NEED_CITE: steel grade equivalence mapping between ASTM A572 and EN 10210 standards]
Understanding the Seamless Cold Drawn Process and Grade Selection
ASTM A572 Gr 50 belongs to the high-strength low-alloy (HSLA) family, offering higher yield strength than carbon structural grades like Q235 or S235JR while maintaining weldability and formability. The cold drawn seamless manufacturing route starts with a solid round billet that is pierced, elongated, and then drawn through a die and mandrel combination — this eliminates the weld seam entirely and produces tighter dimensional tolerance than hot-formed alternatives. For the ASTM A572 Gr 50 seamless square hollow section, the cold drawing process also work-hardens the surface layer, improving resistance to denting and abrasion during handling and service. Surface treatment selection depends on the service environment: hot-dip galvanizing at 40–500 g/m² zinc coating suits outdoor scaffolding and coastal infrastructure where atmospheric corrosion is the primary degradation mechanism, while black or oiled finish works for indoor machinery frames that will receive paint or powder coating after fabrication. Wall thickness tolerance of ±1% to ±5% means that a specified 8 mm wall may measure between 7.6 mm and 8.4 mm — buyers invoiced on theoretical weight should confirm whether the supplier calculates based on nominal or minimum guaranteed thickness. [NEED_CITE: cold drawn seamless steel tube manufacturing process advantages]
Hidden Costs of Procurement Shortcuts
Choosing a supplier who cannot provide heat-number traceability on an ASTM A572 Gr 50 seamless square hollow section creates downstream risk that rarely appears in the initial purchase price comparison. Material substitution — receiving Q345 when A572 Gr 50 was specified — may pass visual inspection but fails structural calculation assumptions, forcing the engineer to either redesign the connection details or reject the entire delivery. Missing or incomplete mill test certificates delay customs clearance in markets with strict import documentation requirements, generating port storage charges that exceed the per-ton price saving. Negative tolerance abuse inflates the per-ton price because the buyer pays for steel that is not physically present in the bundle. [NEED_CITE: consequences of material certification gaps in structural steel procurement]
Why Project Buyers Source This Grade Through Us
We operate three production lines running simultaneously, producing over 20,000 tons monthly across square, rectangular, and round hollow sections — this capacity means your ASTM A572 Gr 50 seamless square hollow section order does not compete for mill time with smaller batch requests. Every bundle leaving our warehouse carries an original mill test certificate showing chemical composition and mechanical properties for that specific heat number, not a generic template. Our 2,800+ specification ready stock covers standard sizes from 15×15 mm to 500×500 mm in square and up to 800×1200 mm in rectangular sections, enabling split shipments and urgent replenishment without waiting for production scheduling. For non-standard dimensions or custom lengths beyond the 5.8–12 m range, we offer 15–25 day lead times with flexible MOQ starting from 1 ton — designed for trial orders before clients commit to full-container volume. Third-party inspection through SGS or BV is available on request, with our team coordinating the inspector’s schedule and providing access to our in-house lab for witness testing. Our export documentation team handles packing lists, bills of lading, certificates of origin, and container loading optimization to maximize payload per 20-foot or 40-foot unit.
Documentation & Compliance
- Mill test certificate documenting ASTM A572 Gr 50 chemical composition (carbon, manganese, phosphorus, sulfur, silicon, columbium, vanadium) and mechanical properties per heat number
- CE certificate covering EN 10210 and EN 10219 for European market structural hollow section compliance
- ISO 9001:2015 quality management system certificate covering production and inspection processes
- SGS or BV third-party inspection report available upon request, covering dimensional verification, surface quality, and mechanical testing witness
- Material traceability documentation linking each bundle to specific heat number and production batch
- Export customs documents including packing list, bill of lading, and certificate of origin formatted for destination country requirements
Packaging, Loading & Delivery
- ASTM A572 Gr 50 seamless square hollow section bundled with steel strips and edge protectors to prevent surface damage during ocean transit
- Galvanized finish tubes wrapped with waterproof cloth and separated by rubber pads to preserve zinc coating integrity
- Container loading optimized for 5.8 m and 12 m lengths to maximize payload within 20-foot and 40-foot standard shipping units
- Custom length cutting available per drawing requirements, with cut ends deburred and protected against corrosion
- Heat number and steel grade stenciled on each bundle tag for site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with door-to-door logistics coordination for project sites
Starting Your ASTM A572 Gr 50 Procurement
Submit your specification sheet covering section dimensions, wall thickness, length, quantity, steel grade confirmation, and destination port — we respond within 12 hours with pricing, available stock status, and production lead time for non-standard sizes. For projects requiring third-party inspection or specific certification packages, confirm these requirements at inquiry stage so we can coordinate SGS/BV scheduling and prepare the complete documentation set before production begins.
Request Your ASTM A572 Gr 50 Seamless Square Hollow Section Quote
Send your specifications via email or WhatsApp to receive factory-direct pricing with mill test certificates included.
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
