Description
Factory-direct Q195 Q235 Q355 black iron square tube RHS steel profile factory price — produced on three dedicated forming lines with in-house mill test certification for every heat number shipped.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q195 Q235 Q355 Black Iron Square Tube RHS Steel Profile |
| Product Type | Square and Rectangular Steel Tube / Hollow Section (RHS/SHS) |
| Steel Grade | Q195, Q235, Q345, Q355, 10#, 20#, 45#, ASTM A500 Gr.B–Gr.50, DIN S235JR, JIS SS400, JIS SPHC, BS 040A10 |
| Standard | ASTM A53, ASTM A53M, GB/T, DIN, JIS, BS |
| Section Shape | Square, Rectangular, Round, Deformed |
| Size Range | 10–3000 mm |
| Wall Thickness | 0.6–15 mm |
| Technique | Hot Rolled, Cold Rolled, ERW |
| Surface Treatment | Black Annealing, Bright Annealing, None Annealing, Galvanized Coated |
| Tolerance | ±0.01% |
| Ends | Plain / Beveled upon request |
| Application | Steel structures, construction frames, machinery, furniture, interior decoration, fluid pipeline, petroleum and natural gas industry, drilling, pipeline |
| MOQ | 20 Tons |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & Infrastructure | Building frames, bridge support columns, scaffolding uprights, glass curtain wall mullions |
| Facade & Architectural | Sharp-corner rectangular tube for exposed steel facades, decorative screen framing |
| Machinery Manufacturing | Conveyor structures, hydraulic cylinder barrels, equipment base frames |
| Steel Structure Fabrication | Welded trusses, portal frame members, purlin and girt systems |
| Pipeline & Energy | Low-pressure fluid conveyance, petroleum casing support, drilling rig substructures |
Why Rounded Corners Fail on Facade Orders and How Q195 Q235 Q355 Black Iron Square Tube RHS Steel Profile Factory Price Solves It
Architectural clients reject containers when corner radii exceed drawing tolerances — true sharp-corner RHS eliminates that risk.
Standard ERW rectangular tubes produce corner radii of R≥2t as a byproduct of the forming process. For glass curtain wall mullions and exposed steel facades, those rounded corners create visible gaps at welded joints and ruin the clean-line aesthetic architects specify. Off-standard dimensions — extra-heavy walls, non-standard side lengths — compound the problem because most mills only roll popular sizes, forcing fabricators to compromise on design or source from multiple suppliers. [NEED_CITE: cold-formed hollow section dimensional tolerance requirements per EN 10219]
Matching Structural Load Paths in Building Frames and Curtain Wall Systems
The Q195 Q235 Q355 black iron square tube RHS steel profile factory price range covers side lengths from 10 mm to 3000 mm and wall thicknesses from 0.6 mm to 15 mm, allowing a single procurement package to serve both light-gauge interior partition framing and heavy-load portal frame columns. Hot rolled sections handle higher point loads in bridge support applications, while cold rolled and ERW tubes deliver the tighter dimensional control that machinery manufacturers require for precision equipment bases. Our patented sharp-corner technology produces true right-angle corners that sit flush against mating plates — critical when facade contractors weld exposed mullion joints and need zero-gap fit-up without secondary grinding.
Engineering Compliance Across EN, ASTM, and JIS Frameworks
Structural engineers designing to EN 1993 or AISC 360 require documented proof that the supplied steel grade meets the referenced standard’s chemical and mechanical thresholds. Q235 corresponds roughly to S235JR under EN 10025 and ASTM A500 Gr.B under U.S. specifications, but equivalence is not automatic — mill test certificates must confirm yield strength, tensile strength, and elongation against the specific standard named on the drawing. [NEED_CITE: steel grade equivalence mapping between GB Q-series and EN S-series] For EU-bound shipments, CE marking under EN 10210 (hot-finished) or EN 10219 (cold-formed) is mandatory for customs clearance; missing or incorrectly referenced CE documentation will hold cargo at the port of discharge. Our in-house physical and chemical laboratory tests every heat for dimensional accuracy, tensile properties, and chemical composition before release.
Decoding Steel Grade Selection and Forming Process for Q195 Q235 Q355 Black Iron Square Tube RHS Steel Profile Factory Price
The Q-series grading system (Q195, Q235, Q345, Q355) designates minimum yield strength in MPa — Q235 yields at approximately 235 MPa, Q355 at 355 MPa — making Q355 the preferred choice for primary structural members where higher load capacity reduces section size and weight. ASTM A500 Gr.B through Gr.50 and DIN S235JR serve equivalent roles in North American and European specifications respectively. Hot rolled tubes undergo forming at temperatures above the steel’s recrystallization point, producing thicker walls suitable for heavy structural columns; cold rolled and ERW tubes are formed at ambient temperature, yielding tighter tolerances and smoother surfaces ideal for visible architectural applications. Surface treatment selection — black annealing for weldability, bright annealing for cosmetic exposure, galvanizing for outdoor corrosion resistance — should align with the service environment specified in the project’s corrosion protection schedule.
Hidden Costs of Procuring the Wrong Grade or Missing Certification
Ordering Q235 when the structural drawing specifies Q355 reduces load capacity and may trigger rejection during third-party inspection at the construction site — forcing costly re-supply and schedule delays. Similarly, shipping CE-marked tubes to the EU without the correct EN 10219 reference on the mill test certificate results in customs holds that can extend clearance by weeks. Negative tolerance abuse — where actual wall thickness falls below the nominal value beyond permissible limits — reduces structural capacity while appearing compliant on paper, creating latent safety risks that surface only during load testing or, worse, under service conditions. [NEED_CITE: consequences of negative tolerance deviation in structural hollow sections]
Why Project Teams Source Q195 Q235 Q355 Black Iron Square Tube RHS Steel Profile Factory Price Through Our Mill
We operate three dedicated forming lines covering 2,800+ specifications — from 10 mm miniature tubes to 3000 mm heavy sections with wall thickness up to 40 mm — eliminating the need to split orders across multiple suppliers. Our 41 invention patents include China’s original sharp-corner rectangular tube technology, filling a gap that standard mills cannot address. Every shipment carries a mill test certificate generated by our in-house laboratory, with third-party inspection by SGS or BV available upon request. Full international certification — ISO 9001:2015, Lloyd’s CE under EN 10210 and EN 10219, Singapore FPC — ensures customs clearance across 50+ export destinations. Custom non-standard sizes, cutting, marking, and professional container loading with anti-damage measures are standard practice, not premium add-ons.
Documentation & Compliance
- Mill test certificate documenting Q195, Q235, or Q355 chemical composition and mechanical properties per GB/T or equivalent EN/ASTM standard
- CE certificate confirming compliance with EN 10210 (hot-finished) or EN 10219 (cold-formed) for EU market import
- ISO 9001:2015 quality management system certificate covering production and testing processes
- SGS or BV third-party inspection report verifying dimensional accuracy and surface quality before shipment
- Material traceability by heat number linking each tube to its corresponding mill test certificate
- Customs documentation including packing list, bill of lading, and certificate of origin for destination-country clearance
Packaging, Loading & Delivery
- Black iron square tubes and RHS profiles bundled with steel strips and seaworthy packaging, sized to match 20ft or 40ft container dimensions for Q195 Q235 Q355 grades
- Slightly oiled surface protection applied to prevent rust during ocean transit, with edge protectors preserving corner geometry on sharp-corner rectangular tubes
- Custom cutting to project-specified lengths within the 10–3000 mm range, reducing on-site waste and secondary processing for construction frame applications
- Heat number and steel grade stenciled on each bundle for site identification and traceability during installation
- Professional container loading with anti-damage bracing to prevent bending or surface scoring of galvanized coated or bright annealed finishes
- FOB, CIF, or DDP shipping terms available with full export documentation and tracking until arrival at destination port or project site
Initiating Your Q195 Q235 Q355 Black Iron Square Tube RHS Steel Profile Factory Price Inquiry
Submit your required dimensions, steel grade, surface treatment preference, quantity, and destination port to receive a detailed quotation within 12 hours — including unit pricing, lead time, and shipping terms. For non-standard sizes or sharp-corner rectangular tubes, our engineering team will confirm feasibility and provide a custom production schedule. Mill test certificates, CE documentation, and third-party inspection reports are confirmed at the quotation stage so there are no surprises at customs or site inspection.
Frequently Asked Questions
Q: How do I confirm that Q235 meets my project’s S235JR or ASTM A500 Gr.B requirement?
A: We provide mill test certificates showing chemical composition and mechanical properties for each heat, allowing your engineer to verify equivalence against EN 10025 or ASTM A500 specifications before shipment.
Q: Can you produce non-standard dimensions outside your listed 10–3000 mm range?
A: Custom non-standard sizes are available with low minimum order quantities; submit your drawing or specification and our technical team will confirm feasibility and lead time.
Q: What surface treatment options are available for the Q195 Q235 Q355 black iron square tube RHS steel profile factory price?
A: Black annealing, bright annealing, none annealing, and galvanized coated finishes are available — selection depends on whether the tubes will be welded, painted, or exposed to corrosive environments.
Q: Do your products carry CE certification for EU import?
A: Yes, our cold-formed hollow sections carry Lloyd’s CE certification under EN 10219, and hot-finished sections under EN 10210, with full documentation provided for customs clearance.
Q: What is the minimum order quantity for standard and custom sizes?
A: The standard MOQ is 20 tons; custom non-standard sizes may have different minimums depending on production setup requirements — confirm at the inquiry stage.
Get Your Q195 Q235 Q355 Black Iron Square Tube RHS Steel Profile Factory Price Quote Today
Send your specifications, steel grade, quantity, and destination to receive pricing and mill test certificate samples within 12 hours.
Contact: Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
Address: No.11889, Jingshi West Road, Lulian Group, Jinan City, Shandong Province, China
