Description
Factory-Direct Mill & Fabrication — Q235B and Q355B plates produced and processed under one roof, eliminating procurement gaps between material suppliers and fabricators.
Technical Specifications
| Parameter | Value |
|---|---|
| Designation | Q235B / Q355B Carbon Steel Plate |
| Product Type | Steel Plate |
| Steel Grade | Q235B, Q355B |
| Standard | AISI, ASTM, BS, DIN |
| Section Shape | Flat Sheet |
| Thickness Range | 3mm, 6mm, 8mm, 10mm, 20mm |
| Length Range | 1000–12000mm |
| Width Range | 600–1100mm |
| Technique | Hot Rolled / Cold Rolled |
| Surface Treatment | Coated |
| Tolerance | ±1% |
| Processing Services | Bending, Welding, Decoiling, Cutting, Punching |
| Application | Building construction, heavy-duty structures, boiler plates, structural steel fabrication |
| MOQ | 1 Ton |
Application Suitability
| Industry | Typical Applications |
|---|---|
| Building Construction | Column base plates, beam splice plates, gusset connections, floor grating supports |
| Heavy-Duty Structures | Crane runway beams, equipment support frames, industrial platform decking |
| Boiler & Pressure Vessels | Boiler end caps, heat exchanger baffles, pressure vessel shell plates |
| Infrastructure & EPC | Bridge gusset plates, foundation anchor plates, conveyor support structures |
Splitting Material Supply and Fabrication Creates Certification Gaps
A single source from raw plate to finished component closes the traceability gap that causes customs holds and site rejections.
When buyers source Q235B Q355B carbon steel plate supplier from one vendor and outsource cutting and welding to another, the material certification chain breaks. Mill test certificates from the plate supplier rarely match the welding procedure records from the fabricator, and project inspectors flag the disconnect during EN 1090 or AISC audits. [NEED_CITE: EN 1090 structural steel fabrication execution class requirements] I have seen shipments held at Middle East ports because the fabricator could not produce weld maps tied to the original heat numbers on the plate. Vertical integration — owning both the steel production line and the fabrication workshop — means every cut piece, every weld, and every coating report traces back to the same heat of steel.
Matching Plate Thickness and Grade to Structural Load Paths
Q235B serves general structural applications where moderate strength suffices — floor plates, secondary beams, and non-critical bracing connections. Q355B steps into higher-load zones: primary column base plates, crane beam flanges, and heavy equipment foundations where increased yield strength reduces plate thickness and overall weight. As a Q235B Q355B carbon steel plate supplier, we supply both grades from the same mill, so engineers can specify the right grade for each connection without managing two separate procurement channels. The ±1% thickness tolerance ensures that design calculations for bearing stress and bolt hole clearance hold true across every plate delivered.
Engineering Compliance for International Structural Projects
Structural steel plates used in EU-bound projects must conform to EN 1090 execution class requirements, which demand full material traceability, certified welding procedures, and documented quality control at every fabrication stage. For Middle East and African infrastructure tenders, ASTM and BS standards often govern material acceptance, and customs authorities require certificates of origin paired with mill test reports matching the shipped heat numbers. [NEED_CITE: steel grade equivalence mapping between Chinese GB and international EN ASTM standards] Our processing services — CNC cutting, plasma and flame cutting, bending, welding (MIG/MAG/SAW), drilling, and punching — all execute against approved shop drawings with WPS and PQR records on file. Coated surface treatment on Q235B Q355B carbon steel plate supplier products adds corrosion protection for outdoor and marine-adjacent installations, reducing the need for on-site blasting and painting.
Understanding Q235B and Q355B Grade Selection and Processing Behavior
The Q-series designation follows the Chinese GB standard system, where the number indicates the minimum yield strength in MPa — Q235B delivers adequate formability and weldability for general construction, while Q355B provides higher strength for demanding structural members. Both grades respond well to hot rolling, which produces a uniform grain structure suitable for welding and bending without pre-heating in most thickness ranges. Cold rolled options offer tighter surface finish and dimensional precision for applications requiring accurate flatness, such as machine base plates and precision jig components. The coated surface treatment applied at the mill protects against transit corrosion and extends storage life before fabrication begins. When plates are cut to custom lengths within the 1000–12000mm range, material waste drops significantly compared to buying standard mill lengths and trimming on site. [NEED_CITE: hot rolled vs cold rolled steel plate surface finish and dimensional accuracy comparison]
Hidden Costs of Unverified Plate Procurement
Ordering Q235B Q355B carbon steel plate supplier products from a trading company that sources plates from unnamed third-party mills creates risk at multiple stages. Without verifiable mill test certificates tied to specific heat numbers, project engineers cannot confirm chemical composition or mechanical properties, leading to failed inspection hold points. Negative tolerance abuse — where actual plate thickness falls below the specified minimum — reduces load-bearing capacity and triggers structural safety concerns during final acceptance. Missing or mismatched documentation causes customs delays at destination ports, demurrage charges accumulate, and project schedules slip. [NEED_CITE: consequences of material certification gaps in international steel procurement]
Why Procurement Teams Choose Our Integrated Supply Chain
We operate our own steel production facility with multiple production lines and maintain over 2,800 raw material specifications in inventory, meaning Q235B and Q355B plates come directly from our mill rather than through external traders. Our fabrication workshop handles the full processing chain — CNC cutting, welding, drilling, bending, shot blasting, and painting — so shop drawings, material certificates, and welding records all originate from a single quality management system. Every shipment includes a complete documentation package: WPS, PQR, weld maps, dimensional inspection reports, and coating reports, prepared by our in-house quality team. Certified welding procedures and qualified welders hold AWS and EN certifications, ensuring compliance with international fabrication standards. Professional loading plans with proper timber separators, edge protectors, and weight distribution calculations prevent plate deformation and edge damage during ocean transit — a lesson learned from early shipments where inadequate lashing led to costly on-site rework.
Documentation & Compliance
- Mill test certificate documenting Q235B and Q355B chemical composition and mechanical properties per GB standard, traceable to individual heat numbers
- CE certificate confirming EN 1090 compliance for structural steel fabrication components exported to European Union markets
- ISO 9001 quality management system certificate covering both steel plate production and fabrication processing operations
- SGS or BV third-party inspection report available for pre-shipment verification of dimensions, surface quality, and coating thickness
- Material traceability records linking each cut piece and welded assembly back to the original heat number and mill test certificate
- Complete customs documentation package including packing list, bill of lading, and certificate of origin for destination port clearance
Packaging, Loading & Delivery
- Q235B and Q355B plates bundled with steel straps and timber separators to prevent surface scratching and edge damage during handling
- Coated surface treatment preserved with waterproof wrapping and edge protectors before container loading for ocean freight
- Custom length plates within the 1000–12000mm range optimized for 20ft and 40ft container loading plans to maximize payload and minimize shipping cost per ton
- CNC cut-to-size plates marked with heat number, steel grade, and piece identification for on-site assembly traceability
- Loading plans specifying weight distribution, lashing points, and dunnage placement for plates exceeding standard container door dimensions
- FOB, CIF, and DDP shipping terms available with door-to-door logistics coordination for project sites in the Middle East, Southeast Asia, and Africa
Starting Your Procurement Process
Share your project drawings (PDF or DWG format) along with steel grade requirements, plate dimensions, quantities, and destination port. Our engineering team responds within 24 hours with a preliminary assessment, detailed quotation covering material, processing, coating, packing, and shipping costs, plus a shop drawing timeline and production schedule.
Get Your Q235B Q355B Carbon Steel Plate Quote with Mill Test Certificates
Submit your specifications and engineering drawings to receive a detailed quotation and complete material documentation package within one business day.
Company: 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 Q235B and Q355B carbon steel plates and which grade suits my project?
A: Q235B offers moderate strength with excellent formability and weldability, making it suitable for general structural applications such as floor plates, secondary beams, and bracing connections. Q355B provides higher yield strength for demanding structural members including primary column base plates, crane beam flanges, and heavy equipment foundations. The choice depends on your structural design loads and engineering specifications.
Q: Can you provide mill test certificates and arrange third-party inspection before shipment?
A: Yes, every Q235B and Q355B plate shipment includes mill test certificates documenting chemical composition and mechanical properties, traceable to specific heat numbers. We also arrange SGS or BV third-party inspection for pre-shipment verification of dimensions, surface quality, coating thickness, and material properties upon request.
Q: What processing services do you offer for carbon steel plates and can you work from our engineering drawings?
A: Our processing services include CNC cutting, plasma and flame cutting, bending, welding (MIG/MAG/SAW), drilling, punching, decoiling, and coated surface treatment. Our engineering team prepares shop drawings from your PDF or DWG files for review and approval before fabrication begins, ensuring dimensional accuracy and compliance with your project specifications.
Q: What are your international certifications and do your products comply with EN 1090, AWS, or AISC standards for EU and Middle East projects?
A: We hold CE certification for EN 1090 structural steel fabrication compliance, ISO 9001 quality management certification, and our welding procedures and welders are certified to AWS and EN standards. Our fabrication processes and documentation packages meet the requirements for projects in the European Union, Middle East, Southeast Asia, and Africa.
Q: How do you handle shipping for oversized steel plates and what is the typical delivery timeline?
A: We develop professional loading plans with timber separators, edge protectors, and weight distribution calculations to prevent plate deformation during ocean transit. For plates exceeding standard container dimensions, we arrange specialized loading and lashing procedures. Shipping terms include FOB, CIF, and DDP with door-to-door logistics coordination, and typical production lead times depend on order quantity and processing complexity.
