Description
Factory-Direct Galvanized SHS/RHS — Own steel mill produces Q235 and Q345 hollow sections with full heat-number traceability from billet to finished tube.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235 Q345 Galvanized Square and Rectangular Steel Tube |
| Product Type | Galvanized Square / Rectangular Steel Tube (SHS / RHS) |
| Steel Grade | Q195, Q235, Q345, 10#, 20#, 45#, 16Mn, A53 (A/B), St37, St42, St35.4, St52.4, Grade B, Grade C, Grade D, Grade 50 |
| Standard | GB, BS EN, AISI, ASTM, DIN, JIS |
| Section Shape | Square / Rectangular / Round |
| Size Range | 10 mm – 1000 mm |
| Wall Thickness | 0.6 – 28 mm |
| Length | 1 – 12 m |
| Technique | Hot Rolled / Cold Rolled / ERW |
| Surface Treatment | Galvanized (Zinc Coating 30–275 g/m²), Bared, Oiled, Color Paint, 3PE |
| Tolerance | ±1% |
| Ends | Plain / Beveled / Threaded with couplings or sockets; plastic caps and steel rings available |
| Application | General engineering structures, automotive, bridges, shipbuilding, boilers, pressure vessels, construction frames, machinery, scaffolding, furniture |
| MOQ | 1 Ton |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Structural frames, columns, beams, platforms, stairways for EPC and general contractor projects |
| Industrial Facilities | Factory buildings, warehouses, logistics centers, machinery frames, pressure vessel supports |
| Bridges & Shipbuilding | Load-bearing structural members, bridge railings, ship deck frames requiring certified material traceability |
| Scaffolding & Furniture | Scaffolding uprights and ledgers, display racks, shelving systems, decorative structural elements |
Material Traceability Gaps Cost More Than the Tube Itself
When galvanized SHS/RHS arrives without verifiable mill certificates, the entire batch becomes a liability.
Overseas buyers sourcing Q235 Q345 galvanized square rectangular steel tube from traders rather than integrated mills frequently discover material certification gaps only after customs inspection or third-party testing at destination. The zinc coating thickness fails specification, the steel grade cannot be traced to a heat number, and the dimensional tolerance exceeds ±1%. Re-galvanizing or returning a container of 6-meter tubes erases any price advantage gained at purchase. [NEED_CITE: material traceability requirements for structural steel in international construction projects]
Matching Galvanized SHS/RHS to Structural Frame Requirements
Galvanized square and rectangular tubes in Q235 and Q345 grades serve as primary load-bearing members in warehouse frames, industrial platforms, and infrastructure support structures. The zinc coating at 30–275 g/m² provides corrosion protection for outdoor and humid environments without additional painting. Side lengths from 10 mm to 1000 mm and wall thicknesses from 0.6 mm to 28 mm cover everything from light-gauge furniture frames to heavy structural columns. Our vertically integrated production — from raw steel billet through ERW or hot/cold rolling to final galvanizing — ensures every Q235 Q345 galvanized square rectangular steel tube carries consistent mechanical properties and coating quality verified by in-process inspection.
Engineering Compliance and Certification for Global Projects
Structural hollow sections used in load-bearing applications must comply with project-specific engineering codes. For European markets, Q235 Q345 galvanized square rectangular steel tube must meet EN 10219 cold-formed or EN 10210 welded hollow section requirements, with CE marking mandatory for structural components. North American projects typically specify ASTM A500 or A53 grades, while Middle East and Southeast Asian EPC contracts often accept GB standards with third-party verification. Wall thickness tolerance of ±1% directly affects structural calculations — undersized tubes fail load testing even when steel grade chemistry is correct. Third-party inspection by SGS, BV, or TÜV before shipment provides the documentation package that customs authorities and project engineers require. [NEED_CITE: EN 10219 cold-formed structural hollow sections compliance requirements]
Steel Grade Selection and Galvanizing Process Fundamentals
Q235 and Q345 represent the two most widely specified carbon structural steel grades in Chinese standards, with Q345 offering higher yield strength for heavier load applications. When projects require international equivalence, Q235 corresponds roughly to S235JR under EN standards and A36 under ASTM, while Q345 aligns with S355JR and A572 Grade 50 respectively. The ERW (Electric Resistance Welding) process produces square and rectangular tubes by forming flat strip into shape and welding the seam — suitable for most structural applications up to moderate wall thicknesses. Hot rolled tubes handle thicker walls and heavier loads, while cold rolled tubes provide tighter dimensional tolerance and smoother surface finish. Galvanizing involves immersing the formed tube in molten zinc, creating a metallurgical bond that provides both barrier protection and cathodic protection against corrosion. Zinc coating weight from 30 g/m² serves indoor or temporary applications, while 275 g/m² withstands aggressive outdoor or marine environments.
Hidden Costs of Non-Compliant Galvanized Tube Procurement
Purchasing Q235 Q345 galvanized square rectangular steel tube without verified certification creates risks that surface during project inspection or customs clearance. Steel grade misidentification — receiving Q195 when Q345 was specified — compromises structural integrity and triggers complete batch rejection. Zinc coating below contract specification fails corrosion resistance requirements, forcing costly re-galvanizing or premature replacement. Negative tolerance exceeding contractual limits reduces actual load-bearing capacity despite passing chemistry tests. Missing mill test certificates or material traceability documentation delays customs clearance and project approval, generating demurrage charges and schedule penalties. [NEED_CITE: consequences of non-compliant structural steel in international construction]
Integrated Mill Production Eliminates Middleman Risk
Our production facility operates three steel production lines with over 2,800 specifications of raw material in stock, enabling direct supply of Q235 Q345 galvanized square rectangular steel tube without trader markup or material substitution risk. The fabrication workshop handles CNC cutting, drilling, welding, and surface treatment under one quality management system, providing complete documentation from billet chemistry through final galvanizing thickness. Certified welding procedures (WPS/PQR) and qualified welders ensure structural connections meet AWS and EN standards. Every shipment includes mill test certificates with heat number traceability, dimensional inspection reports, and coating thickness measurements — the documentation package that international projects require for engineering approval and customs clearance. Professional loading and lashing for oversized cargo prevents transit damage to galvanized coating, while export experience across EU, Middle East, Southeast Asia, and Africa ensures compliance with destination-country import requirements.
Documentation & Compliance
- Mill test certificate documenting Q235 or Q345 chemical composition and mechanical properties per GB/T 700 or GB/T 1591, with heat number traceability to original billet
- CE certificate confirming compliance with EN 10219 or EN 10210 for structural hollow sections used in European construction projects
- ISO 9001 quality management system certificate covering the complete production process from steel melting through galvanizing
- SGS or BV third-party inspection report verifying zinc coating thickness, dimensional tolerance, and surface quality before shipment
- Material traceability documentation linking each Q235 Q345 galvanized square rectangular steel tube bundle to specific heat numbers and production dates
- Complete customs documentation including packing list, bill of lading, and certificate of origin formatted for destination-country import clearance
Packaging, Loading & Delivery
- Q235 Q345 galvanized square rectangular steel tube bundled with steel strips and edge protectors to preserve zinc coating during ocean transit
- Plastic caps installed on tube ends to prevent moisture ingress and coating damage at cut edges for 6-meter and 12-meter lengths
- Galvanized surface inspected and oiled if specified to prevent white rust formation during storage and transportation
- Container loading optimized for 20-foot and 40-foot shipments based on tube dimensions, with wooden cradles preventing contact damage to galvanized coating
- Heat number and steel grade marked on each bundle for site identification and material traceability verification
- FOB, CIF, and DDP shipping terms available with professional export documentation and tracking until site delivery
Initiating Your Galvanized SHS/RHS Procurement
Submit project drawings, steel grade requirements (Q235 or Q345), dimensions, quantities, and destination port to receive detailed quotation including material, fabrication, galvanizing, and shipping costs. Our engineering team reviews shop drawings and provides material optimization recommendations within 24 hours. Confirm certification requirements (CE, EN, ASTM) and third-party inspection needs before production begins to ensure documentation compliance for your project.
Request Quotation with Mill Test Certificate
Share your Q235 Q345 galvanized square rectangular steel tube specifications and project requirements to receive pricing and material certification details.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjystructure.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjystructure.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: What is the difference between Q235 and Q345 steel grades for galvanized square and rectangular tubes?
A: Q235 and Q345 are Chinese standard carbon structural steel grades, with Q345 offering higher yield strength suitable for heavier load-bearing applications. Q235 corresponds approximately to S235JR (EN) and A36 (ASTM), while Q345 aligns with S355JR (EN) and A572 Grade 50 (ASTM). Selection depends on structural load requirements and project engineering specifications.
Q: Can you provide third-party inspection for galvanized SHS/RHS before shipment?
A: Yes, we accept third-party inspection by SGS, BV, TÜV, or other internationally recognized inspection agencies. Inspection covers zinc coating thickness measurement, dimensional tolerance verification, surface quality assessment, and visual examination. The inspection report becomes part of the complete documentation package for your project.
Q: What zinc coating thickness options are available for galvanized rectangular tubes?
A: Zinc coating ranges from 30 g/m² to 275 g/m² depending on application environment. Lighter coatings (30–60 g/m²) suit indoor or temporary applications, while heavier coatings (180–275 g/m²) provide long-term corrosion protection for outdoor, industrial, or marine environments. Coating weight is specified in purchase orders and verified by inspection reports.
Q: Do you offer custom cutting and fabrication services for galvanized square tubes?
A: Yes, our fabrication workshop provides CNC cutting, drilling, welding, bending, and surface treatment services for galvanized SHS/RHS. Custom lengths from 1 to 12 meters, hole drilling, beveled ends, and welded assemblies are available per engineering drawings. Shop drawing review and material optimization support ensure fabrication accuracy before production begins.
Q: What documentation is provided with each shipment of galvanized steel tubes?
A: Each shipment includes mill test certificates with heat number traceability, dimensional inspection reports, zinc coating thickness measurements, packing lists, bills of lading, and certificates of origin. CE certificates and third-party inspection reports are provided when specified. All documentation supports customs clearance and project engineering approval requirements.
