Description
Factory-Direct SHS Supply — Every ASTM A53 GRB square hollow section tube rolls from certified mills with original MTC and ships under our direct QC, cutting out trader markups on structural hollow sections.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | ASTM A53 GRB Square Hollow Section Tube |
| Product Type | Square Steel Tube (Hollow Section) |
| Steel Grade | Gr.B, S235, S275, S355, STK400 |
| Standard | ASTM A500, ASTM A53, GB/T 3091 |
| Section Shape | Square |
| Size Range | 19mm × 19mm – 800mm × 800mm |
| Wall Thickness | 1 – 30 mm |
| Length | 5.8m / 6m / 11.8m / 12m / Random Length |
| Technique | Welded (ERW) / Seamless |
| Surface Treatment | Black Painting / Galvanized / Varnish / Bare |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Steel structures / Building frames / Curtain wall / Support tubes / Construction structures / Fertilizer equipment |
| MOQ | 5 Tons |
| Origin | China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Steel Fabrication Workshops | Load-bearing frames, column supports, truss bracing using ASTM A53 GRB square hollow section tube |
| Commercial Construction | Curtain wall mullions, facade support grids, roof purlin systems |
| Infrastructure & Civil Engineering | Bridge handrail posts, highway sign gantry legs, sound-barrier supports |
| Industrial Equipment | Fertilizer plant pipe racks, conveyor support legs, equipment bases |
| Shipyards & Offshore | Deckhouse framing, non-pressure structural supports on commercial vessels |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a 10mm-wall ASTM A53 GRB square hollow section tube means ±0.1mm — tight enough to keep connection plates flush and weld prep consistent.
When buyers source square hollow sections across mixed batches, inconsistent wall thickness forces fabricators to re-measure every piece before welding. Thinner-than-declared walls reduce load capacity silently; thicker walls throw off theoretical weight calculations and trigger overweight penalties at port. Missing or forged mill certificates mean the heat number cannot be traced back to chemical composition, leaving engineers unable to verify whether Gr.B actually meets ASTM A53 yield requirements. [NEED_CITE: ASTM A53 mechanical property requirements for Grade B]
Matching SHS Profiles to Structural Frame Requirements
An ASTM A53 GRB square hollow section tube in S355 grade with 10–20mm wall thickness carries significantly higher point loads than thin-wall ERW sections used for non-structural cladding. For curtain wall systems, 19×19mm to 100×100mm sections in 1.5–3mm thickness provide adequate rigidity while keeping weight low for anchor-point design. Heavy-wall seamless options up to 800×800mm × 30mm WT serve equipment bases and fertilizer plant pipe racks where vibration and dynamic loads demand solid corner integrity. We supply both ERW and seamless process routes from the same order, so fabricators get weldable thin-wall and high-strength thick-wall from one shipment.
Engineering Compliance and Certification Pathways
Structural hollow sections used in load-bearing frames must conform to recognized standards — ASTM A500 for North American projects, EN 10219 for European construction, and GB/T 3091 for domestic Chinese infrastructure. [NEED_CITE: EN 10219 cold-formed structural hollow section dimensional tolerances] Surface treatment selection directly affects service life: hot-dip galvanized ASTM A53 GRB square hollow section tube resists corrosion in outdoor and coastal environments, while black painted or varnished finish suits indoor structural frames where appearance matters less than cost. For projects requiring CE marking or third-party inspection, we arrange SGS or BV surveyors to witness dimensional checks and witness cutting before container sealing.
Decoding Steel Grades and Manufacturing Processes
The ASTM A53 GRB square hollow section tube sits in a carbon steel category where Gr.B requires minimum 240 MPa yield — a baseline for general structural use. European equivalents like S235, S275, and S355 offer progressively higher yield strength, allowing engineers to downsize sections and reduce tonnage without sacrificing load capacity. STK400, a Japanese structural grade, aligns closely with S275JR and serves projects specifying JIS standards. ERW welded tubes suit most structural applications where cost efficiency and consistent dimensions matter; seamless options eliminate the weld seam entirely, preferred for high-stress zones or where ultrasonic inspection of the weld line is impractical. Wall thickness from 1mm to 30mm covers everything from light gauge curtain wall studs to heavy-duty column sections, with ±1% tolerance holding dimensional accuracy across the full range. [NEED_CITE: steel grade equivalence between ASTM A53, EN 10025, and JIS G3101]
The Hidden Cost of Wrong-Grade Procurement
Substituting an unverified S235 tube for a specified ASTM A53 GRB square hollow section tube may pass visual inspection but fails under structural load calculations — the yield strength gap between grades can mean the difference between code compliance and catastrophic deflection. Missing mill test certificates block customs clearance in markets requiring proof of origin and material conformity. Negative tolerance abuse — where actual wall thickness falls below the declared minimum — reduces section modulus and compromises fire resistance ratings. [NEED_CITE: structural steel traceability requirements under EN 1090]
Why Fabricators and EPCs Source From Us
We operate as a factory-direct supplier, meaning every ASTM A53 GRB square hollow section tube ships with original mill test certificates traceable by heat number — no trader relabeling. Our inventory spans 19×19mm to 800×800mm in both ERW and seamless, so a single order covering curtain wall studs and heavy column sections consolidates into one shipment. Custom cutting to exact project lengths eliminates on-site waste and reduces freight on air. Every batch undergoes dimensional inspection covering side length, wall thickness, and straightness before release. We hold ISO 9001:2015 certification and arrange SGS or BV third-party inspection for clients requiring independent verification. Professional heavy-cargo loading using flatbed and open-top containers prevents damage to galvanized surfaces and ensures weight distribution stays within port limits.
Documentation & Compliance
- Mill test certificate documenting Gr.B chemical composition and mechanical properties per ASTM A53, with heat number traceability for every ASTM A53 GRB square hollow section tube
- CE conformity declaration for EN 10219 structural hollow sections when shipping to European Union markets
- ISO 9001:2015 quality management certificate covering production, inspection, and dispatch processes
- SGS or BV third-party inspection report available upon request, covering dimensional checks, surface quality, and witness testing
- Material traceability sheet linking each bundle to its heat number, rolling date, and mill of origin
- Full customs documentation including packing list, bill of lading, and certificate of origin for import clearance
Packaging, Loading & Delivery
- ERW welded ASTM A53 GRB square hollow section tube bundled with high-tensile steel strips and edge protectors to prevent corner damage during ocean transit
- Galvanized sections wrapped in waterproof paper and loaded with timber separators to preserve zinc coating integrity across 6m and 12m lengths
- Custom cut-to-size orders packed by project tag with heat number stenciled on each piece for on-site traceability
- Open-top container loading for 800×800mm heavy-wall sections exceeding standard container door height, with weight distribution calculated to avoid port overweight penalties
- FOB, CIF, and DDP shipping terms available, with professional flatbed and break-bulk logistics for project cargo exceeding container capacity
- Bundle tags display steel grade (Gr.B / S355), size, wall thickness, heat number, and length for immediate site identification
Getting Your Quote and Mill Test Certificate
Send your ASTM A53 GRB square hollow section tube inquiry with section size, wall thickness, length, quantity, surface treatment, and destination port. We return a detailed quotation within 12 hours, including material cost, processing fees, and shipping terms. Original mill test certificates ship with every order or are available for pre-shipment review.
Request Your ASTM A53 GRB SHS Quote with MTC
Submit your size, grade, and quantity to receive pricing and mill test certificates within 12 hours.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjyplate.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjyplate.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: What is the grade equivalence between ASTM A53 GRB, EN S235/S355, and GB Q345B?
A: ASTM A53 Gr.B requires minimum 240 MPa yield strength, placing it close to S235JR in the EN system. S355JR and S355J2 offer higher yield for structural downsizing. GB Q345B (now redesignated Q355B under GB/T 1591-2018) aligns closely with S355JR. We provide cross-reference documentation for projects requiring grade substitution approval from the specifying engineer.
Q: How can I verify the mill test certificate before shipment?
A: Every ASTM A53 GRB square hollow section tube ships with an original MTC showing heat number, chemical composition, and mechanical properties. You can request the MTC before production or dispatch for review. We also arrange SGS or BV third-party inspection to witness dimensional checks and material testing at the mill.
Q: ERW welded or seamless — which process suits my structural application?
A: ERW welded square tubes suit most general structural applications including building frames, curtain walls, and support structures where cost efficiency and dimensional consistency matter. Seamless options eliminate the weld seam and are preferred for high-stress zones, heavy-wall columns, or applications where weld-line inspection is impractical. We supply both from the same order.
Q: What is your MOQ and can you cut to custom lengths?
A: The minimum order quantity is 5 tons per size. We offer custom cut-to-size processing for lengths within the 5.8m to 12m range, with plain ends as standard. Custom cutting reduces on-site waste and allows precise fit-up for fabrication workshops.
Q: Which surface treatment should I choose for outdoor structural use?
A: Hot-dip galvanized ASTM A53 GRB square hollow section tube provides long-term corrosion resistance for outdoor, coastal, and industrial environments. Black painted or varnished finish suits indoor applications where cost is prioritized. Bare sections are available for projects where the buyer applies their own coating system on-site.
