Description
Factory-Direct ERW Rectangular Tubes — Q345 grade rectangular hollow sections produced under ASTM A213 and DIN EN 10217-1, shipped with original mill test certificates and professional heavy cargo loading plans.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q345 Rectangular Steel Tube |
| Product Type | Rectangular Steel Tube (Welded / ERW) |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Rectangular |
| Size Range | 300×300 mm and custom dimensions |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Custom (per customer request) |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Structural Oil Pipes, Fluid Pipe, Boiler Pipe, Gas Pipe, Chemical Fertilizer Pipe, Structure Pipe |
| MOQ | 5 Tons |
| Origin | China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Oil & Gas Infrastructure | Structural oil pipes, fluid transport lines, gas distribution frames |
| Construction & Engineering | Building frames, column supports, machinery bases, conveyor structures |
| Industrial Scaffolding | Load-bearing scaffolding systems, temporary structural supports |
| Pressure Equipment | Boiler tubes, pressure vessel supports, chemical fertilizer plant piping |
What Wall-Thickness Tolerance Costs on a Q345 Rectangular Steel Tube Order
A ±1% tolerance on a 300×300 ERW rectangular tube means the difference between passing structural inspection and facing on-site rework.
Buyers sourcing Q345 Rectangular Steel Tube ERW ASTM Custom Sizes Supplier products for structural frames often discover that inconsistent wall thickness leads to welding gaps, misaligned connections, and load-bearing miscalculations. When tubes arrive with hidden negative tolerance beyond acceptable limits, fabricators face unexpected weight shortfalls and structural engineers question the integrity of the entire frame. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Q345 Rectangular Tubes to Structural Oil Pipe Applications
The Q345 grade delivers higher yield strength than Q235, making it suitable for structural oil pipes where internal pressure and external loads combine. ERW welding produces a continuous seam with consistent mechanical properties along the tube length, while the hot rolled surface with slight oiling protects against corrosion during ocean transit. Our loading team designs custom bracing schemes for 300×300 mm sections to prevent corner deformation during container shipping — a lesson learned from early export shipments where improper fixation caused entire container rejections at destination ports.
Engineering Compliance and Certification Requirements
Structural applications requiring ASTM A213 or DIN EN 10217-1 compliance demand full traceability from heat number to finished tube. The Q345 grade meets Chinese GB standards while maintaining equivalence with international specifications for structural and pressure applications. [NEED_CITE: steel grade equivalence between GB Q345 and international standards] Third-party inspection through SGS or BV verifies chemical composition and mechanical properties before shipment, ensuring customs clearance in destination countries with strict import documentation requirements. Custom cutting and bending services allow fabricators to receive tubes ready for welding, reducing on-site processing time and material waste.
Understanding Q345 Steel Grade and ERW Welding Process
The Q-series steel grades (Q195, Q215, Q235, Q345) follow Chinese national standards where the number indicates minimum yield strength in MPa. Q345 provides approximately 40% higher yield strength than Q235, making it the preferred choice for load-bearing structures and pressure-containing applications. ERW (Electric Resistance Welded) technology uses high-frequency current to fuse the tube seam without filler material, producing a weld zone with mechanical properties matching the base metal. This process suits rectangular and square sections where dimensional accuracy and surface finish matter more than extreme pressure ratings.
Hot rolled surface treatment leaves a mill scale layer that provides basic corrosion protection during storage and transit. Slight oiling adds an additional barrier against moisture, essential for ocean freight to tropical climates. The ±1% tolerance on wall thickness ensures that theoretical weight calculations match actual delivered weight within acceptable margins, preventing disputes over short-weight claims. [NEED_CITE: ERW welded tube manufacturing process and quality control standards]
Hidden Costs of Incorrect Grade Selection and Certification Gaps
Choosing Q235 when structural calculations require Q345 leads to undersized members that fail load testing, forcing complete frame replacement. Missing or forged mill test certificates trigger customs holds at destination ports, delaying projects and generating demurrage charges. Tubes with excessive negative tolerance arrive lighter than ordered, creating disputes over payment and requiring supplementary material orders that delay construction schedules. [NEED_CITE: mill test certificate verification procedures for steel imports]
Why Source Q345 Rectangular Tubes from XJY Plate
We operate as a dedicated plate and coil division within Shandong Xin Jiyuan Special Steel Tube Co., Ltd, focusing exclusively on flat steel products with full traceability from mill to job site. Every Q345 Rectangular Steel Tube ERW ASTM Custom Sizes Supplier order ships with original mill test certificates showing heat number, chemical composition, and mechanical properties. Our logistics team designs container loading plans specifically for heavy rectangular sections, using custom bracing and weight distribution to prevent transit damage. Custom cutting, punching, and bending services allow you to receive tubes ready for assembly, reducing fabrication time and labor costs. ISO 9001:2015 and CE certification ensure production meets international quality standards, while SGS/BV third-party inspection provides independent verification for projects requiring additional documentation.
Documentation & Compliance
- Mill test certificate documenting Q345 chemical composition and mechanical properties per ASTM A213, with heat number traceability
- CE certificate confirming compliance with DIN EN 10217-1 for pressure and structural applications
- ISO 9001:2015 quality management certificate covering production processes and inspection procedures
- SGS or BV third-party inspection report available upon request for projects requiring independent verification
- Material traceability documentation linking each tube to specific heat number and production batch
- Complete customs documentation including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Q345 rectangular tubes bundled with steel strips and edge protectors to preserve hot rolled surface during handling and transit
- Slight oiling applied to all tubes before packaging to prevent corrosion during ocean freight to humid climates
- Custom loading plans for 300×300 mm sections using wooden bracing and weight distribution to prevent corner deformation in 40GP containers
- Custom cutting to specified lengths with deburred ends, ready for welding upon arrival at fabrication shop
- Heat number and Q345 grade stenciled on each tube bundle for on-site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional heavy cargo logistics experience in flatbed and open-top container loading
Requesting Quotation and Technical Documentation for Your Project
Submit your specifications including steel grade (Q195-Q345), dimensions, wall thickness, length, quantity, and destination port to receive a detailed quotation within 12 hours. We provide original mill test certificates before shipment for your quality verification, along with custom cutting and processing options to match your fabrication requirements. Confirm your certification needs (CE, ASTM, third-party inspection) and loading requirements to ensure smooth customs clearance and damage-free delivery.
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 steel grades for rectangular tubes?
A: Q345 provides higher yield strength than Q235, making it suitable for load-bearing structures and pressure applications. The Q-series follows Chinese GB standards where the number indicates minimum yield strength in MPa.
Q: Can you provide mill test certificates for Q345 Rectangular Steel Tube ERW ASTM Custom Sizes Supplier orders?
A: Yes, every order ships with original mill test certificates showing heat number, chemical composition, and mechanical properties per ASTM A213 and DIN EN 10217-1 standards.
Q: What is the minimum order quantity for custom-sized rectangular tubes?
A: The MOQ is 5 tons. We can produce custom dimensions and lengths within the 300×300 mm range and other specifications based on your project requirements.
Q: Do you offer custom cutting and processing services?
A: Yes, we provide welding, punching, cutting, bending, and decoiling services. Tubes can be cut to your specified lengths with deburred ends, ready for fabrication upon arrival.
Q: How do you ensure tubes arrive without damage during ocean freight?
A: Our logistics team designs custom loading plans with wooden bracing and weight distribution specifically for heavy rectangular sections. Slight oiling protects the surface during transit, and edge protectors prevent damage from steel stripping.
Get Your Q345 Rectangular Tube Quote with Mill Test Certificates
Send your specifications to admin@xjyplate.com or contact us via WhatsApp at +86 188 5315 7756 to receive pricing, delivery schedule, and technical documentation for your structural oil pipe or construction frame project.
