Description
Factory-Direct Bulk Supply — 3 production lines running simultaneously with 20,000+ tons monthly capacity, delivering Q235 Q345 S355JR square and rectangular steel tubes at competitive pricing with no middlemen markup.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345/S355JR Square and Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (SHS/RHS) |
| Steel Grade | Q195, Q235, Q345, S235JR, S275JR, S355JR |
| Standard | AISI, API |
| Section Shape | Square / Rectangular |
| Size Range | 1×1 inch (25×25mm) and above |
| Wall Thickness | 0.9mm–1.4mm and above |
| Length | 6m / 6.4m / 12m |
| Technique | Hot Rolled / ERW |
| Surface Treatment | Black (Non-oiled) |
| Tolerance | ±1% |
| Ends | Plain |
| Processing Service | Bending, Cutting, Welding, Punching |
| Application | Structure Pipe, Fluid Pipe, Boiler Pipe, Hydraulic Pipe, Gas Pipe, Oil Pipe, Construction frames, Machinery, Steel structures |
| MOQ | 5 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding systems, portal frames for warehouses |
| Machinery Manufacturing | Conveyor structures, equipment bases, hydraulic cylinder housings |
| Energy & Petrochemical | Gas pipelines, oil transport systems, boiler tubes |
| Steel Fabrication | Structural columns, trusses, bracing members for industrial facilities |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
±1% tolerance control prevents weight discrepancies that trigger engineering rejections at site inspection.
When procurement teams source ASTM A500 carbon steel square rectangular tube supplier shipments from fragmented vendors, inconsistent wall thickness becomes a silent budget killer. A batch arriving with negative tolerance beyond acceptable limits means theoretical weight calculations fail to match actual load-bearing capacity. Engineers discover the discrepancy only during third-party inspection or structural load testing, forcing costly replacements and project delays. Material traceability gaps compound the problem—without original mill test certificates linking each batch to heat numbers, customs authorities hold shipments at port while compliance documentation gets sorted. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Structural Load Requirements for Construction Frames
ASTM A500 carbon steel square rectangular tube supplier inventory spanning Q195 through S355JR grades addresses varying load demands across construction applications. Q235 serves light-duty framing where cost efficiency takes priority, while S355JR delivers higher yield strength for heavy-load portal frames and multi-story building columns. The ±1% wall thickness tolerance ensures calculated section properties match actual performance, eliminating surprises during structural engineering verification. Hot rolled black finish provides adequate corrosion resistance for indoor applications, while the 6m and 12m standard lengths minimize on-site welding connections for faster erection sequences.
Engineering Compliance and Certification Requirements
Structural steel procurement for international projects demands certification alignment with destination market regulations. ASTM A500 carbon steel square rectangular tube supplier documentation must include mill test certificates showing chemical composition and mechanical properties per specified standards. European construction projects require CE marking under EN 10210/10219, while North American projects reference ASTM A500 Grade B or C specifications. Third-party inspection from SGS or BV provides independent verification for projects with stringent quality requirements. [NEED_CITE: steel grade equivalence between Chinese GB standards and international EN/ASTM specifications]
Steel Grade Selection and Manufacturing Process Impact
The progression from Q195 to Q345 to S355JR represents increasing yield strength capacity, directly influencing section size requirements and structural economy. Q-series grades (Q195, Q235, Q345) follow Chinese GB standards, while S-series (S235JR, S275JR, S355JR) conform to European EN specifications—both systems offer equivalent performance when properly specified. ERW (Electric Resistance Welded) manufacturing produces consistent weld seams suitable for structural applications up to moderate pressure ratings, while hot rolled processes deliver uniform mechanical properties across the entire cross-section. Wall thickness selection between 0.9mm and heavier gauges balances weight optimization against buckling resistance requirements. Surface treatment choices—black non-oiled for indoor use versus galvanized for outdoor exposure—affect both initial cost and long-term maintenance budgets.
Hidden Costs of Incorrect Material Procurement
Specifying incorrect steel grades or accepting undocumented tolerance deviations creates downstream expenses that dwarf initial purchase price differences. Material substitution without engineering approval voids structural warranties and insurance coverage. Missing mill test certificates trigger customs holds, generating demurrage charges while documentation gaps get resolved. Negative tolerance beyond specification limits reduces actual load capacity, potentially requiring supplementary reinforcement or complete member replacement. [NEED_CITE: consequences of dimensional tolerance non-compliance in structural steel construction]
Why Procurement Teams Choose Our Supply Chain
Factory-direct pricing eliminates trading company margins, passing volume discounts directly to bulk purchasers. Our in-house metallurgical laboratory conducts three-stage inspection on every production batch, generating original mill test certificates that trace each shipment to specific heat numbers. Full inventory coverage across 2,800+ specifications enables rapid fulfillment without waiting for production scheduling. ISO 9001:2015 certification and Lloyd’s CE approval under EN 10210/10219 satisfy international quality requirements. Professional export teams optimize container loading plans, maximizing payload per shipment while protecting surface finish during ocean transit. Flexible MOQ policies accommodate both trial orders and full-container bulk purchases.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345/S355JR chemical composition and mechanical properties per AISI/API standards
- CE certificate confirming EN 10210/EN 10219 compliance for European market construction projects
- ISO 9001:2015 quality management system certification covering production and inspection processes
- SGS or BV third-party inspection reports available for projects requiring independent verification
- Material traceability documentation linking each bundle to heat numbers and production dates
- Complete customs documentation package including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Hot rolled black finish square and rectangular tubes bundled with steel strips, edge protectors preventing surface damage during handling
- 6m and 12m standard lengths optimized for 20ft and 40ft container loading, maximizing payload efficiency
- Plain ends capped to prevent debris ingress during ocean transit and storage
- Heat number and steel grade markings stenciled on each bundle for site identification and traceability
- FOB, CIF, and DDP delivery terms available with professional customs clearance support
- Container loading plans optimized by export team to prevent shifting and protect ±1% tolerance integrity
Initiating Your Bulk Procurement Process
Submit your specifications including section dimensions, wall thickness, steel grade requirements, total quantity, and destination port to receive competitive bulk pricing within 12 hours. Request original mill test certificates and third-party inspection options for projects with stringent compliance requirements. Our technical team provides custom cutting and processing services to match your fabrication sequence requirements.
Frequently Asked Questions
Q: What is the difference between Q235, Q345, and S355JR steel grades?
A: Q235 and Q345 follow Chinese GB standards with yield strengths of 235 MPa and 345 MPa respectively. S355JR conforms to European EN standards with 355 MPa yield strength. All three grades serve structural applications, with selection depending on project specifications and destination market requirements.
Q: Can you provide mill test certificates for ASTM A500 carbon steel square rectangular tube supplier shipments?
A: Yes, every batch ships with original mill test certificates documenting chemical composition and mechanical properties. Certificates trace material to specific heat numbers and confirm compliance with specified standards including AISI and API requirements.
Q: What is the minimum order quantity for square and rectangular steel tubes?
A: Standard MOQ is 5 tons for regular specifications. Trial orders starting from 1 ton are available for new customers evaluating material quality before committing to larger volumes.
Q: Do you offer custom cutting and processing services?
A: Yes, we provide bending, cutting, welding, and punching services to match your fabrication requirements. Custom lengths beyond standard 6m and 12m options are available for bulk orders.
Q: What third-party inspection options are available?
A: SGS and BV inspection services are available upon request. Our in-house laboratory conducts three-stage inspection on every production batch, with independent verification providing additional assurance for projects with stringent quality requirements.
Secure Competitive Pricing for Your Next Project
Submit your specifications via email or WhatsApp to receive bulk pricing with volume discounts, delivery schedules, and mill test certificate options.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxinjiyuan.com
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxinjiyuan.com
