Description
Factory-Direct Galvanized SHS/RHS — Q235 and Q345 square and rectangular tubes rolled, galvanized, and inspected in-house before shipment.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235/Q345 Galvanized Square & Rectangular Steel Tube |
| Product Type | Galvanized Square and Rectangular Steel Tube (SHS/RHS) |
| Steel Grade | Q195, Q235, Q345, STK400, STK500, S235, S355 |
| Standard | ASTM, JIS, ISO 9001, CE, API |
| Section Shape | Square / Rectangular |
| Size Range | Wall Thickness 1.0 mm – 2.0 mm |
| Length | 6 – 12 m |
| Technique | Hot Rolled Based |
| Surface Treatment | Galvanized Coated (Z41 – Z60) |
| Spangle Type | Regular Spangle |
| Hardness | Mid Hard |
| Skin Pass | Yes |
| Oiled or Non-oiled | Non-oiled |
| Tolerance | ±1% |
| Processing Service | Welding, Punching, Cutting, Bending, Decoiling |
| Application | Making pipes, cutting sheets, making containers, making corrugated sheets, making small tools, making fences |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Structural frames, scaffolding systems, perimeter fencing, gate posts |
| Industrial Manufacturing | Container chassis, corrugated roofing sheets, small hand tools |
| Agricultural & Storage | Greenhouse skeletons, equipment shelters, pallet racking uprights |
| Municipal & Civil Works | Road sign posts, lighting pole bases, drainage channel supports |
When ±1% Thickness Tolerance Becomes the Real Cost Driver on a Fence-Line Order
Tight wall tolerance on thin-gauge galvanized SHS/RHS prevents cumulative stack-up errors across long runs.
On perimeter fencing and scaffolding projects, buyers often accept standard mill tolerance — then find that 0.2 mm negative deviation on a 1.2 mm wall compounds over 200 posts into misaligned connector plates and rejected weld joints. Coating inconsistency between Z41 and Z60 adds another layer: thinner zinc spots corrode first at cut edges, forcing re-galvanizing or early replacement. Missing heat-number traceability on the mill test certificate turns a routine customs check into a two-week port hold. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
Matching Thin-Wall Galvanized RHS to Light Structural Frames
Q235 and Q345 grades in 1.0–2.0 mm wall thickness serve load-bearing frames where weight matters more than brute strength — greenhouse skeletons, signage gantries, and modular container corners. The regular spangle finish with skin pass gives a uniform zinc layer that accepts powder coating without peeling, while the ±1% tolerance keeps connector plates flush. As a Q235 Q345 galvanized square rectangular steel tube supplier, we run every batch through in-house thickness gauges before galvanizing, catching negative-tolerance rolls before they reach the zinc bath.
Engineering Compliance for Galvanized SHS in Corrosive Environments
Light structural applications in coastal or industrial zones need zinc coating that survives handling and decades of salt exposure. Z60 coating on Q345 RHS meets typical marine-adjacent fencing and signage requirements, while Q235 with Z41 suffices for inland agricultural shelters. CE certification and ISO 9001 traceability satisfy EU and international customs, and JIS-compliant STK400/STK500 grades open Japanese-spec infrastructure tenders. Cut-to-length and punching services eliminate on-site secondary work that would otherwise expose raw steel edges. [NEED_CITE: hot-dip galvanized coating thickness standards for structural steel]
Decoding Q-Grade vs S-Grade Steel in Galvanized Rectangular Tubes
Q235 and Q345 follow the Chinese GB system where the number denotes minimum yield strength in MPa — Q235 yields at 235 MPa, Q345 at 345 MPa. Their European equivalents S235 and S355 follow the same logic under EN standards. STK400 and STK500 are JIS structural tube grades for general and welded structures respectively. Hot-rolled base material gives better corner radii than cold-formed alternatives, reducing stress concentration at welded joints. Skin pass treatment after galvanizing flattens microscopic zinc spangles, improving paint adhesion and surface uniformity across the Q235 Q345 galvanized square rectangular steel tube supplier’s output.
The Hidden Price of Accepting “Standard Tolerance” on Thin-Wall Tubes
Ordering 1.2 mm wall galvanized RHS at standard mill tolerance often means receiving 1.05 mm actual — a 12% weight shortfall that shows up as structural deflection under design load. Welding thin-wall tubes with inconsistent zinc thickness produces porosity at joints, requiring grind-out and re-weld that delays project handover. Missing mill test certificates with heat numbers trigger third-party inspection demands at destination port, adding thousands in demurrage. [NEED_CITE: consequences of negative tolerance in structural hollow sections]
Procurement Confidence from Mill to Port
Every Q235 Q345 galvanized square rectangular steel tube supplier order ships with original mill test certificates showing chemical composition and mechanical properties per heat number. Our in-house理化实验室 tests coating thickness before bundling — no third-party surprises at destination. Custom cutting, punching, and bending to drawing eliminate site waste, while professional flatbed and open-top container loading prevents zinc coating damage during transit. ISO 9001 and CE certification satisfy international compliance, with SGS or BV third-party inspection available on request.
Documentation & Compliance
- Mill test certificate documenting Q235/Q345 chemical composition and yield strength per GB/T 6728
- CE certificate confirming compliance with EN 10219 for cold-formed structural hollow sections
- ISO 9001:2015 quality management certificate covering galvanizing and finishing processes
- SGS or BV third-party inspection report verifying zinc coating thickness Z41–Z60
- Full material traceability by heat number from steelmaking to final bundle
- Export customs documents including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Galvanized SHS/RHS bundled with steel strips and edge protectors to preserve Z41–Z60 zinc coating during ocean transit
- Non-oiled surface with regular spangle finish wrapped in waterproof paper for 6–12 m lengths
- Open-top container or flatbed loading optimized for 1.0–2.0 mm wall thickness to prevent crushing
- Custom cut-to-length service available before bundling, with dimensional reports per order
- Heat number and steel grade stenciled on each bundle for site identification
- FOB, CIF, and DDP shipping terms with professional heavy cargo logistics experience
Getting Your Quote Right the First Time
Send your drawing or specification sheet listing steel grade (Q235/Q345/S235/S355), section dimensions, wall thickness, length, coating requirement (Z41 or Z60), and destination port. We return a detailed quotation with material cost, processing fees, and shipping terms within 12 hours, along with a sample mill test certificate for your quality team’s review.
Start Your Q235 Q345 Galvanized SHS/RHS Order
Submit your specifications to receive pricing, mill test certificates, and lead time confirmation.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.xjyplate.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@xjyplate.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
Frequently Asked Questions
Q: How do Q235 and Q345 map to S235/S355 or ASTM equivalents?
A: Q235 corresponds to S235 in the EN system and roughly ASTM A36; Q345 maps to S355 and ASTM A572 Grade 50. We provide full equivalence documentation with every shipment.
Q: Can you provide original mill test certificates and arrange third-party inspection?
A: Yes. Every bundle ships with an original MTC showing heat number, chemical composition, and mechanical properties. SGS or BV inspection can be arranged at our facility before shipment.
Q: Do you offer custom cutting and what is the minimum order quantity?
A: We provide cutting, punching, bending, and welding services to your drawings. MOQ varies by section size and coating requirement — contact us with your specs for exact quantities.
Q: What is the difference between Z41 and Z60 galvanized coating?
A: Z41 and Z60 refer to zinc coating mass in grams per square meter. Z60 provides thicker corrosion protection suitable for outdoor or humid environments, while Z41 suffices for indoor or sheltered applications.
Q: How do you handle shipping for heavy galvanized tubes?
A: We use flatbed trucks, open-top containers, or break-bulk vessels depending on order volume and destination. Professional loading prevents coating damage and ensures accurate weight distribution.
