Description
Factory-Direct Carbon Steel Flat Bar Supply — Q235B A36 S235 S355 S400 carbon steel flat bar supplier producing hot-rolled sections with ±1% thickness tolerance, shipped from our own Shandong facility with full mill test certification.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B A36 S235 S355 S400 Carbon Steel Flat Bar |
| Product Type | Hot-Rolved Carbon Steel Flat Bar |
| Steel Grade | Q235B, A36, S235JR, S355JR, S400 |
| Standard | GB/T 700, ASTM A36, EN 10025-2 |
| Section Shape | Flat Bar (Rectangular Solid Section) |
| Size Range | 20×3 mm – 200×20 mm |
| Length | 6 m, 12 m, or cut-to-length |
| Technique | Hot-Rolled |
| Surface Treatment | Black finish (as-rolled), oiled or bare |
| Tolerance | ±1% on thickness, ±2% on width |
| Ends | Mill edge, square-cut |
| Application | Structural framing, machinery bases, bracket fabrication, welding stock |
| MOQ | 5 tons per size |
| Origin | Shandong, China |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Construction & EPC | Column base plates, beam stiffeners, embedded anchor plates |
| Machinery Manufacturing | Machine bed frames, conveyor support rails, hydraulic bracket stock |
| Steel Structure Fabrication | Gusset plates, connection tabs, splice plates for H-beam assemblies |
| Infrastructure & Bridge Works | Bearing pads, expansion joint supports, parapet anchoring bars |
| Steel Service Centers | Slitting and shearing stock for downstream distribution |
What Thickness Tolerance Errors Cost on a Flat Bar Structural Order
A flat bar that measures 9.7 mm instead of 10 mm can fail load calculations and trigger full-batch rejection at site inspection.
When procurement teams source Q235B A36 S235 S355 S400 carbon steel flat bar supplier stock from mixed traders, thickness drift beyond ±1% is common — especially on thinner gauges below 6 mm. The result: weld prep dimensions are wrong, base plate bearing areas shrink, and structural engineers cannot sign off on as-built conditions. [NEED_CITE: EN 10058 hot-rolled flat steel dimensional tolerance requirements]
Worse, if the mill test certificate does not match the physical material — a frequent issue when traders blend heats — customs authorities in EU and Middle East markets will hold the shipment pending re-inspection. The delay costs more than the steel itself.
How Hot-Rolled Flat Bars Match Structural and Fabrication Demands
Hot-rolled flat bars in grades Q235B through S400 deliver consistent grain flow along the rolling direction, making them suitable for load-bearing brackets and welded connections where through-thickness integrity matters. Our Q235B A36 S235 S355 S400 carbon steel flat bar supplier production runs maintain uniform surface quality for direct welding without additional grinding — critical for EPC contractors working to tight erection schedules.
Engineering Compliance and Grade Selection for Flat Bar Applications
Structural flat bars used in load-bearing frames must conform to EN 10058 for hot-rolled sections or equivalent national standards. Grade selection directly affects weldability and impact performance: S235JR suits general construction, while S355JR provides higher yield strength for heavier spans without increasing section size. For projects targeting CE marking under EN 1090, the flat bar must carry a valid Factory Production Control certificate traceable to the production heat. [NEED_CITE: EN 1090 structural steel component certification requirements]
Steel Grade Equivalence and Rolling Process Explained
Q235B (GB/T 700) and A36 (ASTM A36) occupy the same yield strength range and are interchangeable for non-critical structural use. S235JR and S355JR follow the EN 10025-2 designation system, where the number indicates minimum yield strength in MPa. Hot-rolling at temperatures above 900°C produces a mill scale surface that provides short-term corrosion resistance but requires removal before painting in aggressive environments. Our flat bars are supplied with light oil coating to prevent white rust during transit — a detail often skipped by traders storing material in open yards.
Hidden Costs of Sourcing Flat Bars from Unverified Traders
Material misidentification is the most expensive flat bar procurement failure. A batch labeled S355JR that actually contains S235-grade steel will pass visual inspection but fail mechanical testing at the project lab — forcing complete replacement and schedule delays. Missing or forged mill test certificates trigger customs holds in regulated markets. [NEED_CITE: steel grade equivalence between EN 10025 and ASTM A36 standards]
Why Project Teams Source Flat Bars Directly from Our Mill
We operate three dedicated rolling lines producing flat bars alongside our hollow section range, allowing combined container loading that reduces freight cost per ton. Every heat is tested in our in-house laboratory for chemical composition and tensile properties before release. Our 2,800+ specification inventory covers flat bars from 20×3 mm to 200×20 mm in all five grades — eliminating the need to split orders across multiple suppliers. Full CE certification under EN 10025-2 and ISO 9001:2015 ensures documentation acceptance in EU, Singapore, and GCC markets. We have exported to 50+ countries with professional container loading that prevents edge damage and bundling shift during ocean transit.
Documentation & Compliance
- Mill test certificate documenting Q235B/A36/S235/S355/S400 chemical composition and tensile properties per GB/T 700, ASTM A36, or EN 10025-2
- CE certificate covering hot-rolled flat bars under EN 10025-2 Factory Production Control
- ISO 9001:2015 quality management certificate for production and testing processes
- SGS or BV third-party inspection report available per client request before shipment
- Full material traceability by heat number linking physical bars to test records
- Export documentation including packing list, bill of lading, and certificate of origin
Packaging, Loading & Delivery
- Flat bars bundled with high-tensile steel strips at 1.5 m intervals, wrapped with waterproof paper to protect oiled surface during humid ocean transit
- Edge protectors applied to all bundles to prevent corner damage from strap tension on thinner gauges below 8 mm
- Container loading optimized by length grouping — 6 m bars loaded transversely in 20ft containers, 12 m bars in 40ft open-top or flat-rack units
- Cut-to-length service available for 12 m stock reduced to site-specific dimensions, reducing on-site cutting waste
- Heat number and grade stenciled on each bundle end for immediate site identification and traceability
- FOB, CIF, and DDP shipping terms available with full container tracking until port discharge
How to Request a Flat Bar Quotation with Mill Documentation
Submit your flat bar specification including grade, dimensions, total tonnage, and destination port — we return a detailed quotation with unit pricing, production lead time, and available mill test certificate samples within 12 hours. For non-standard sizes outside our 20×3 to 200×20 mm range, we provide custom rolling options with minimum order confirmation.
Get Your Flat Bar Quote with Full Mill Test Certification
Send your flat bar dimensions, grade requirement, and quantity to receive pricing and documentation samples.
Shandong Xin Jiyuan Special Steel Tube Co., Ltd
Website: www.sdxjypipe.com
Tel: +86 531 8573 6315
Mobile/WhatsApp/WeChat: +86 188 5315 7756
Email: admin@sdxjypipe.com
