Description
Factory-Direct Q235 Rectangular Welded Steel Tube Supply — ERW hollow sections produced in-house with full ASTM and EN standard compliance, shipped directly from our Jinan mill to your project site.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Rectangular Welded Steel Tube |
| Product Type | Rectangular Welded Steel Tube / Hollow Section |
| Steel Grade | Q195, Q215, Q235, Q345 |
| Standard | ASTM A213, DIN EN 10217-1 |
| Section Shape | Rectangular |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Hot Rolled / Slightly Oiled |
| Tolerance | ±1% |
| Length | Customizable (Customers’ Request) |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Fluid Pipe, Boiler Pipe, Drill Pipe, Gas Pipe, Oil Pipe, Chemical Fertilizer Pipe, Structure Pipe |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, column supports, truss systems for industrial warehouses |
| Oil & Gas | Gas transmission lines, oil transport pipelines, drilling support structures |
| Chemical Processing | Chemical fertilizer transport piping, process fluid conveyance systems |
| Power Generation | Boiler tubes, heat exchanger supports, structural framing for power plants |
| Machinery Manufacturing | Equipment frames, conveyor support structures, hydraulic system housings |
What Dimensional Tolerance Actually Costs on a Structural Frame Order
±1% tolerance on Q235 rectangular welded steel tube means the difference between on-site fit-up and costly rework.
When structural engineers specify rectangular hollow sections for load-bearing frames, even minor deviations in wall thickness or outer dimensions compound across dozens of connection points. A Q235 rectangular welded steel tube that measures outside tolerance forces fabricators to either reject the batch or grind and re-weld connections — both eating into project margins. We have seen orders delayed because suppliers quoted ±3% tolerance as “industry standard,” but the receiving engineer’s drawings demanded tighter control. For fluid and gas transport applications, wall thickness consistency directly affects pressure ratings and weld integrity at joints. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Q235 Rectangular Welded Steel Tube to Structural and Fluid Applications
The Q195 through Q345 grade range covers light structural framing up to heavy-load industrial supports. For building frames and column systems, Q235 offers adequate yield strength for non-critical load paths while keeping material costs controlled. When the same Q235 rectangular welded steel tube moves into oil and gas piping or boiler applications, the ERW weld seam quality and ±1% wall tolerance become the deciding factors for pressure containment. Hot rolled surface with slight oiling provides short-term corrosion protection during storage and transit, sufficient for indoor structural use or projects where final coating will be applied on-site.
Engineering Compliance and Certification Requirements
Structural applications in the EU require EN 10219 compliance with CE marking for hollow sections used in load-bearing systems. North American projects typically specify ASTM standards, and the equivalence between Q235 and ASTM A500 Gr.B must be documented in mill test certificates to pass customs and engineering review. [NEED_CITE: steel grade equivalence between GB Q-series and ASTM standards] Boiler and pressure-containing applications demand additional scrutiny on weld seam integrity and chemical composition reporting. Custom length cutting and punching services allow fabricators to receive ready-to-install components, reducing on-site labor and waste. Third-party inspection from SGS or BV verifies dimensional accuracy and material traceability before shipment.
Understanding ERW Welding Process and Grade Selection
ERW (Electric Resistance Welded) rectangular tubes form from hot rolled coil through continuous rolling and high-frequency welding, producing a consistent weld seam along the length. This process suits medium-wall thickness applications where cost efficiency matters more than the extreme pressure ratings of seamless alternatives. Q195 and Q215 grades serve light structural and non-pressure applications, while Q235 and Q345 step up yield strength for heavier frames and industrial supports. The slight oiling surface treatment prevents rust during ocean transit and warehouse storage without interfering with subsequent painting or galvanizing. [NEED_CITE: ERW versus seamless steel tube manufacturing process differences] Wall thickness tolerance of ±1% ensures that theoretical weight calculations match actual delivered weight, preventing disputes over tonnage-based pricing.
Hidden Costs of Incorrect Grade or Tolerance Selection
Ordering Q195 when the structural drawing calls for Q345 creates a safety liability that only surfaces during load testing or inspection. Missing CE documentation blocks EU customs clearance, stranding containers at port while demurrage charges accumulate. Tolerance beyond ±1% forces fabricators to sort tubes by actual dimension, adding labor costs and delaying assembly. [NEED_CITE: consequences of non-compliant steel imports in regulated markets] Material without proper heat number traceability fails third-party inspection, requiring replacement shipments that miss project deadlines. These costs rarely appear in the initial purchase price comparison.
Why Source Q235 Rectangular Welded Steel Tube From Our Mill
Our Jinan facility operates dedicated ERW lines for rectangular hollow sections, producing Q195 through Q345 grades under ISO 9001:2015 quality management. In-house physical and chemical laboratories test every heat for composition and mechanical properties, generating mill test certificates that accompany each shipment. We hold CE certification under EN 10219 for European market compliance and maintain SGS and BV verification for third-party inspection requests. Custom length cutting, punching, and bending services convert standard tubes into project-ready components. Professional container loading with anti-damage bracing prevents the bending and surface damage that plagued my early shipments to Southeast Asia. Full export documentation including certificate of origin and packing lists ensures smooth customs clearance across 50+ destination countries.
Documentation & Compliance
- Mill test certificate documenting Q235 chemical composition and mechanical properties per ASTM A213 and DIN EN 10217-1
- CE certificate confirming EN 10219 compliance for rectangular hollow sections exported to European markets
- ISO 9001:2015 quality management certificate covering ERW welding and dimensional inspection processes
- SGS or BV third-party inspection report verifying wall thickness tolerance and surface quality before shipment
- Material traceability by heat number linking each Q235 rectangular welded steel tube to its production batch and test results
- Complete customs documentation including packing list, bill of lading, and certificate of origin for destination country clearance
Packaging, Loading & Delivery
- Q235 rectangular welded steel tubes bundled with steel strips and edge protectors to prevent surface damage during ocean transit
- Slight oiling surface treatment preserved by waterproof wrapping for containers shipped to humid coastal destinations
- Custom length tubes cut to project specifications and loaded with wooden spacers to maintain straightness in 20ft and 40ft containers
- Heat number and steel grade stenciled on each bundle for on-site identification and traceability verification
- FOB, CIF, and DDP shipping terms available with professional loading supervision to prevent shifting and bending during transit
- MOQ of 5 tons allows smaller project orders while maintaining competitive per-ton pricing for Q195 through Q345 grades
Starting Your Q235 Rectangular Welded Steel Tube Procurement
Submit your required dimensions, steel grade, quantity, and destination port to receive a detailed quotation within 12 hours. We provide mill test certificates and third-party inspection options before production begins, ensuring material compliance with your project specifications. Custom length cutting and processing services are quoted alongside standard tube pricing for complete project sourcing.
Request Your Q235 Rectangular Welded Steel Tube Quotation
Send your specifications, steel grade requirements, and destination details to receive pricing, lead time, and mill test certificate samples.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Website: www.sdxjypipe.com
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 steel grades for rectangular tubes?
A: Q235 and Q345 differ primarily in yield strength, with Q345 offering higher load-bearing capacity for heavy structural applications. Q235 suits general construction frames and fluid transport, while Q345 serves industrial structures requiring greater strength. Both grades are available in our Q235 rectangular welded steel tube range with full mill test certification.
Q: Can you provide third-party inspection reports for ASTM and EN compliance?
A: Yes, we arrange SGS or BV third-party inspection before shipment to verify dimensional tolerance, surface quality, and material compliance with ASTM A213 or DIN EN 10217-1 standards. Inspection reports accompany the mill test certificate for complete documentation.
Q: What is the MOQ for custom-length Q235 rectangular welded steel tube?
A: The minimum order quantity is 5 tons, which applies to both standard and custom-length tubes. Custom cutting, punching, and bending services are available within this MOQ threshold.
Q: How do you ensure dimensional tolerance of ±1% during ERW production?
A: Our in-house laboratory performs dimensional inspection on every production batch using calibrated gauges and ultrasonic thickness measurement. The ±1% tolerance covers wall thickness and outer dimensions, verified against ASTM and EN standard requirements.
Q: What surface treatment options are available for corrosion protection?
A: Standard Q235 rectangular welded steel tube ships with hot rolled surface and slight oiling for short-term rust prevention during storage and transit. Additional treatments such as galvanizing or painting can be arranged based on project requirements and destination environment.
