Description
Factory-Direct Rectangular Hollow Sections — XJY Plate supplies Q235 and Q355 rectangular hollow steel tubes in sizes from 20×40 mm to 300×500 mm, shipped with original mill test certificates and full heat-number traceability.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 / Q355 Rectangular Hollow Steel Tube |
| Product Type | Square / Rectangular Steel Tube (Hollow Section) |
| Steel Grade | Q195, Q215, Q235, Q345 (Q355), #20, #45; Equivalent: S195, S235JR, S355JR, A53 Grade A/B, A500 Grade A/B/C, STK400, SS400, ST42.2 |
| Standard | EN 10219, EN 10210, GB/T 6728, JIS G3466, ASTM A500, ASTM A53, ASTM A36 |
| Section Shape | Square / Rectangular |
| Size Range | Square: 20×20 mm – 500×500 mm; Rectangular: 20×40 mm – 300×500 mm |
| Wall Thickness | 1.2 mm – 20 mm |
| Length | 3 m – 12 m (random / cut-to-length) |
| Technique | Hot Rolled / Welded (ERW) |
| Surface Treatment | Black (Oiled / Non-oiled), Pre-galvanized (40–80 g/m²), Hot-dip Galvanized (200–600 g/m²) |
| Tolerance | ±1% |
| Ends | Plain |
| Application | Construction / Building structures, Steel structure engineering, Solar power support, Machinery manufacturing, Fence post, Greenhouse frame, Shipbuilding, Power engineering |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Building Structures | Column and beam frames for warehouses, industrial workshops, and commercial buildings |
| Solar & Renewable Energy | Mounting structures for ground-mounted and rooftop solar arrays |
| Infrastructure & Civil Works | Bridge handrails, highway guardrail posts, and lighting pole bases |
| Machinery Manufacturing | Equipment frames, conveyor supports, and crane boom sections |
| Agriculture | Greenhouse framing and irrigation support structures |
| Shipbuilding & Marine | Deck structures and non-pressure internal framing on commercial vessels |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a Q355 rectangular hollow steel tube is not a paperwork detail — it determines whether your frame passes dimensional inspection or gets rejected at the welding stage.
On a recent high-rise warehouse project in Southeast Asia, the contractor received rectangular hollow sections labeled Q355 but with wall thickness running below the lower tolerance limit. The beams warped during welding because the actual section modulus was lower than calculated. The entire batch had to be scrapped, delaying the project by weeks. [NEED_CITE: EN 10219 cold-formed structural hollow section dimensional tolerance requirements]
Buyers sourcing a Q235 Q355 rectangular hollow steel tube supplier often face three compounding risks: inconsistent equivalence mapping between GB, EN, and ASTM grades; hidden negative tolerance practices that reduce actual load-bearing capacity; and missing or forged mill test certificates that fail third-party inspection at the destination port. [NEED_CITE: steel grade equivalence between GB Q-series and EN S-series standards]
Matching Rectangular Hollow Sections to Structural Load Paths
A Q235 Q355 rectangular hollow steel tube performs differently depending on whether it serves as a primary load-bearing column, a secondary purlin, or a non-structural enclosure frame. For primary structural members in buildings and bridges, the higher yield strength of Q355 (equivalent to S355JR per EN 10219) provides the section modulus needed to resist bending moments without excessive deflection. In solar mounting and greenhouse applications, the hot-dip galvanized finish at 200–600 g/m² protects against continuous outdoor exposure, while pre-galvanized at 40–80 g/m² suits indoor or short-term temporary structures. XJY Plate supplies each size from 20×40 mm up to 300×500 mm with wall thickness from 1.2 mm to 20 mm, and provides dimensional inspection reports confirming actual measurements before loading — not just the values printed on the mill certificate.
Engineering Compliance and Certification Requirements
Structural hollow sections used in load-bearing frames must conform to recognized standards: EN 10219 for cold-formed welded structural hollow sections in European projects, ASTM A500 for North American construction, and GB/T 6728 for domestic Chinese projects. [NEED_CITE: EN 10219 and ASTM A500 compliance requirements for structural hollow sections] The Q235 Q355 rectangular hollow steel tube supplied by XJY Plate meets EN 10219, EN 10210, ASTM A500, ASTM A53, and JIS G3466, with CE certification under Lloyd’s register for European customs clearance. For projects requiring third-party verification, SGS or BV inspection is available before shipment. Cut-to-length service from 3 m to 12 m eliminates on-site cutting waste, and plain ends are ready for welding, bolting, or mechanical connection per project specifications.
Steel Grade Equivalence and Manufacturing Process Explained
The Q-series (Q235, Q355) follows the Chinese GB standard system, where the number indicates the minimum yield strength in MPa. The S-series (S235JR, S355JR) follows the European EN system, and ASTM A500 Grade A/B/C follows the North American system. While the yield strength designations align closely, the chemical composition limits and impact testing requirements differ — S355JR requires Charpy impact testing at 20°C, while Q355 does not always mandate this by default. [NEED_CITE: steel grade equivalence between EN, ASTM, and GB standards for structural hollow sections]
The ERW (Electric Resistance Welded) process used for these rectangular hollow sections produces a longitudinal weld seam with consistent quality suitable for structural applications up to moderate wall thickness. Hot-rolled hollow sections per EN 10210 offer superior corner mechanical properties for heavy-load applications, while ERW per EN 10219 provides cost efficiency for standard construction frames. Surface treatment selection depends on the service environment: black oiled finish suits indoor or painted applications, pre-galvanized provides basic corrosion resistance for sheltered outdoor use, and hot-dip galvanized delivers long-term protection for exposed or marine-adjacent environments.
The Hidden Cost of Unverified Tolerance and Grade Substitution
Purchasing a Q235 Q355 rectangular hollow steel tube supplier without verified mill test certificates creates downstream risks that far exceed the initial price difference. Material substitution — receiving Q235 when Q355 was specified — reduces the load-bearing capacity of structural members and may cause failure during engineering inspection or, worse, under service load. [NEED_CITE: consequences of steel grade misidentification in structural engineering] Negative tolerance abuse, where actual wall thickness falls below the specified minimum, reduces the section modulus and compromises fire resistance ratings. Customs authorities in the EU and Middle East increasingly require CE-marked documentation and verifiable heat numbers; shipments without proper certification face rejection or costly re-inspection at the port.
Why Project Procurement Teams Source Hollow Sections from XJY Plate
XJY Plate operates as a dedicated plate and coil division under Shandong Xin Jiyuan Special Steel Tube Co., Ltd, supplying structural steel directly from mill production without intermediary traders. Every Q235 Q355 rectangular hollow steel tube shipped carries an original mill test certificate with heat number, chemical composition, and mechanical properties — verified against the physical stock before loading. The company holds ISO 9001:2015 certification and Lloyd’s CE certification for EN 10219 and EN 10210 products, enabling smooth customs clearance across European and international markets. With a ready stock covering square sections from 20×20 mm to 500×500 mm and rectangular sections from 20×40 mm to 300×500 mm, XJY Plate eliminates the need to source from multiple suppliers for different size requirements. Custom cutting, leveling, and blanking services are available for project-specific lengths, and professional heavy-cargo logistics — including flatbed, open-top container, and break-bulk shipping — ensures safe delivery of long-length sections without damage or overweight penalties.
Documentation & Compliance
- Mill Test Certificate documenting Q235/Q355 chemical composition, yield strength, and tensile properties per GB/T 6728 and EN 10219, with traceable heat number for every batch
- CE Certificate under Lloyd’s register confirming compliance with EN 10219 and EN 10210 for cold-formed and hot-rolled structural hollow sections
- ISO 9001:2015 Quality Management System certificate covering the full supply chain from mill production to final inspection
- SGS or BV Third-Party Inspection Report available upon request, verifying dimensional accuracy, surface quality, and coating thickness before shipment
- Material Traceability Record linking each bundle to its heat number, mill test certificate, and shipping mark for full audit compliance
- Customs Documentation including commercial invoice, packing list, bill of lading, and certificate of origin formatted for destination-port clearance
Packaging, Loading & Delivery
- Q235 and Q355 rectangular hollow steel tubes bundled with steel strips and edge protectors to prevent surface damage to black oiled or galvanized finishes during transit
- Hot-dip galvanized sections (200–600 g/m²) wrapped with waterproof paper and plastic film to preserve zinc coating integrity during ocean freight
- Container loading optimized for 3 m to 12 m lengths using open-top or flat-rack containers for oversized rectangular sections beyond standard door dimensions
- Cut-to-length service available for project-specific requirements, reducing on-site waste and improving loading efficiency per container
- Each bundle marked with heat number, steel grade (Q235/Q355), section dimensions, wall thickness, and length for immediate site identification
- Shipping terms available as FOB, CIF, or DDP with professional heavy-cargo logistics coordination from Shandong port to destination worldwide
Start Your Rectangular Hollow Section Procurement
Submit your required steel grade (Q235, Q355, or equivalent international standard), section dimensions, wall thickness, length, quantity, and destination port to receive a detailed quotation including material cost, processing fees, and shipping terms within 12 hours. XJY Plate provides original mill test certificates for quality verification before shipment and supports third-party inspection by SGS or BV upon request.
Request a Quote with Mill Test Certificate
Send your specifications to admin@xjyplate.com or contact via WhatsApp/WeChat at +86 188 5315 7756 for pricing, lead time, and certification confirmation on your Q235 Q355 rectangular hollow steel tube order.
Frequently Asked Questions
Q: How do Q235 and Q355 compare to S235JR and S355JR in international standards?
A: Q235 corresponds closely to S235JR under EN 10219, and Q355 aligns with S355JR in terms of minimum yield strength. However, chemical composition limits and impact testing requirements may differ between the GB and EN systems. XJY Plate provides documented equivalence mapping and original mill test certificates showing actual chemical and mechanical properties for each batch.
Q: Can you provide mill test certificates and accept third-party inspection?
A: Yes. Every shipment of Q235 Q355 rectangular hollow steel tube includes an original mill test certificate with heat number, chemical composition, and mechanical properties. SGS or BV third-party inspection is available before shipment to verify dimensional accuracy, surface quality, and coating thickness.
Q: What is the minimum order quantity, and can you produce non-standard dimensions?
A: The minimum order quantity is 1 Ton. XJY Plate supplies standard rectangular sections from 20×40 mm to 300×500 mm with wall thickness from 1.2 mm to 20 mm. Custom cutting to specific lengths between 3 m and 12 m is available, and non-standard dimensions can be discussed based on mill production schedules.
Q: When should I choose black oiled, pre-galvanized, or hot-dip galvanized finish?
A: Black oiled finish is suitable for indoor applications or projects where the steel will be painted after installation. Pre-galvanized (40–80 g/m²) provides basic corrosion resistance for sheltered outdoor or temporary structures. Hot-dip galvanized (200–600 g/m²) is recommended for long-term outdoor exposure, marine environments, or solar mounting structures where corrosion protection is critical.
Q: What are the standard delivery terms and container loading options?
A: XJY Plate offers FOB, CIF, and DDP shipping terms. Standard-length sections (3 m to 6 m) ship in regular containers, while longer sections (up to 12 m) require open-top or flat-rack containers. Professional heavy-cargo loading ensures safe transit without damage or overweight penalties.
Get Your Q235 Q355 Rectangular Hollow Steel Tube Quote Today
Send your project specifications — steel grade, dimensions, wall thickness, length, quantity, and destination — to admin@xjyplate.com or reach us at +86 188 5315 7756 (WhatsApp/WeChat) to receive a detailed quotation with mill test certificate preview and estimated delivery timeline.
