Description
Factory-direct ERW SHS/RHS supply — Q195 to Q345 grades rolled on three in-house lines with original mill test certificates for every heat.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q195/Q235/Q345 ERW Square/Rectangular Steel Tube |
| Product Type | Square and Rectangular Steel Tube (SHS/RHS) |
| Steel Grade | Q195, Q235, Q345 |
| Standard | ASTM |
| Section Shape | Square / Rectangular |
| Size Range | 10×10 – 1000×1000 mm |
| Wall Thickness | 0.5 – 40 mm |
| Length | 1 – 12 m |
| Technique | ERW (Electric Resistance Welded) |
| Surface Treatment | Galvanized |
| Tolerance | ±1% |
| Ends | Plain (default) |
| Processing Service | Welding, Punching, Cutting |
| Application | Steel structures, Construction frames, Machinery, Scaffolding, Furniture |
| MOQ | 25 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, scaffolding systems, structural columns and beams |
| Machinery & Equipment | Machine bases, conveyor structures, industrial platform supports |
| Furniture & Commercial | Light-gauge square tubes for retail displays, indoor framing, decorative structures |
What Wall-Thickness Tolerance Costs on a Structural Frame Order
A ±1% tolerance on a Q235 Q345 ERW square rectangular steel tube supplier shipment keeps theoretical weight aligned with structural calculations — drift beyond that triggers re-engineering or outright rejection at site.
I have watched a container of RHS arrive at a West African port with bottom-row tubes flattened into ovals because the loader ignored wall-thickness limits when stacking. The negative tolerance had cre past the acceptable band, and the ellipticity failed the project’s geometric acceptance criteria. The entire consignment was written off. When you source a Q235 Q345 ERW square rectangular steel tube supplier that controls tolerance at the rolling stage rather than sorting it out at the gate, you avoid that loss entirely. [NEED_CITE: EN 10219 cold-formed hollow section dimensional tolerance requirements]
How Galvanized ERW Tubes Match Structural and Scaffolding Demands
The galvanized coating on Q195 through Q345 ERW sections gives scaffolding and outdoor structural frames the corrosion buffer they need without a separate painting step. Wall thickness from 0.5 mm covers light furniture framing, while 40 mm walls carry heavy machinery bases. A Q235 Q345 ERW square rectangular steel tube supplier that stocks the full 10×10 to 1000×1000 mm range lets you consolidate structural columns, purlins, and bracing in one container instead of splitting across three vendors.
Engineering Compliance and Certification Pathways
Projects specifying ASTM standards for North American delivery or EN 10210/EN 10219 for European markets need traceable documentation from the mill, not a reissued warehouse sheet. Steel grade selection — Q195 for non-load-bearing partitions, Q235 for general framing, Q345 for primary structural members — must align with the design engineer’s load calculations. Galvanized finish satisfies most outdoor and industrial atmosphere exposure classes, while plain ends allow on-site welding without coating removal delays. Third-party inspection by SGS or BV confirms chemistry and dimensions before the container is sealed. [NEED_CITE: steel grade equivalence between Chinese GB and ASTM standards]
Steel Grade Selection and ERW Process Fundamentals
Q195, Q235, and Q345 represent ascending yield strength tiers in the Chinese GB system — Q195 suits light-duty applications where formability matters more than load capacity, Q235 covers the majority of construction framing, and Q345 serves primary structural members requiring higher moment resistance. ERW welding forms the tube from coil through continuous roll-forming and resistance-welds the seam without filler metal, producing a consistent weld zone suitable for structural hollow sections. The galvanized coating applied after forming provides uniform zinc coverage on both external and internal surfaces, protecting the weld seam from corrosion. Wall thickness tolerance of ±1% ensures that the delivered weight matches purchase-order calculations — a critical factor when freight cost is tied to theoretical mass. [NEED_CITE: ERW versus seamless hollow section manufacturing comparison]
Hidden Costs of Sourcing the Wrong Grade or Unverified Tolerance
Ordering Q235 when the structural drawing calls for Q345 means the frame will deflect beyond allowable limits under design load — discovered only after erection, when replacement requires crane remobilization and schedule collapse. Missing or forged mill test certificates trigger customs holds at destination ports, demurrage charges accumulating daily. Tubes rolled beyond negative tolerance limits pass the weight check at the mill but fail dimensional inspection at site, forcing the buyer to absorb both the replacement cost and the idle labor. [NEED_CITE: consequences of non-compliant steel material certification in international trade]
Why Buyers Return for Repeat Orders
Every batch rolls through our own ERW lines in Jinan, so the Q235 Q345 ERW square rectangular steel tube supplier price you receive has no trading-company margin layered on top. Our in-house lab issues original mill test certificates tied to heat numbers — the same document your inspector or customs authority will request. We hold ready stock across the 10×10 to 1000×1000 mm range and 0.5–40 mm wall thickness spectrum, so a trial order of 25 tons and a repeat order of 500 tons both ship from the same yard without waiting for a new production campaign. CE (EN 10210/EN 10219), ISO 9001:2015, and FPC certifications cover European and global compliance requirements. Our export team builds container loading plans that respect tube geometry — square and rectangular sections stack differently than round pipe, and a bad plan crushes the bottom layer.
Documentation & Compliance
- Mill test certificate documenting Q195/Q235/Q345 chemical composition and mechanical properties per ASTM, tied to individual heat numbers
- CE certificate covering EN 10210 (seamless) and EN 10219 (welded) hollow section requirements for European market delivery
- ISO 9001:2015 quality management system certificate covering the full ERW production and galvanizing process
- SGS or BV third-party inspection report verifying dimensions, coating thickness, and weld integrity before shipment
- Material traceability sheet linking each bundle to its heat number, rolling date, and galvanizing batch
- Export customs documents including packing list, bill of lading, and certificate of origin formatted for destination-port clearance
Packaging, Loading & Delivery
- Galvanized Q195–Q345 tubes bundled with steel strips and edge protectors to preserve the zinc coating during ocean transit
- Seaworthy packaging with waterproof wrapping for 1–12 m lengths, sized to fit 20-foot and 40-foot container internal dimensions
- Container loading plan issued per order, optimizing weight distribution for 10×10 through 1000×1000 mm sections to prevent bottom-layer deformation
- Custom cutting to project-specific lengths available before shipment, reducing on-site waste and handling
- Heat number and steel grade stenciled on each bundle for site-level traceability and inspection verification
- FOB, CIF, and DDP terms available with door-to-door logistics coordination for destination-port or project-site delivery
Start Your Procurement with Verified Specifications
Submit your drawing list or specification sheet — section dimensions, wall thickness, steel grade, quantity, and destination port — and receive a bulk quotation with volume-based pricing, production lead time, and available mill test certificate formats within one working day. Our team will confirm whether your required dimensions fall within ready stock or need a custom rolling campaign, and advise on the most efficient container loading configuration for your order.
Request a Quote with Mill Test Certificate
Send your specifications to admin@sdxinjiyuan.com or reach us via WhatsApp at +86 188 5315 7756. Our Qingdao-based export team responds within 12 hours with pricing, certification availability, and loading plan confirmation.
