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Q235B SHS Square Hollow Section Steel Tube GB/T 6728-2017 Structural Steel Tube 40×40-400×400mm
Q235B SHS Square Hollow Section Steel Tube
Q235B square hollow section (SHS) belongs to carbon structural steel tubing, produced in line with GB/T 6728‑2017. Thanks to its hollow square geometry, this grade balances good mechanical strength, consistent dimension tolerance and easy workability, making it a reliable option for everyday structural builds.
We stock square sizes spanning 40×40 mm up to 400×400 mm, alongside wall thickness options between 2.5 mm and 16 mm. 6 m and 12 m are our regular mill lengths; bespoke lengths up to 21 m can be arranged to match individual project specifications.
This SHS grade sees frequent use for steel framing, light‑load structures, workshop erection, support assemblies and a broad range of building‑related works.
| Item | Specification |
| Product | Q235B SHS Square Hollow Section |
| Steel Grade | Q235B |
| Standard | GB/T 6728-2017 |
| Shape | Square |
| Size Range | 40×40–400×400mm |
| Wall Thickness | 2.5–16mm |
| Minimum Yield Strength | ≥235 MPa |
| Tensile Strength | ≥375 MPa |
| Standard Length | 6m, 12m |
| Maximum Length | Up to 21m |
| Surface | Black / customized |
| Application | General steel frames, light-duty structures |
Q235B is one of the most popular carbon structural steels, extensively deployed across general construction and metal fabrication work.
It strikes a good balance between mechanical strength, weld performance and machining capability, well‑suited for structural components that demand moderate load‑bearing capacity.
Minimum Yield Strength: ≥235 MPa
Tensile Strength: ≥375 MPa
For exact chemical makeup and mechanical values, always refer to GB/T 6728‑2017 standards and the mill test certificate provided with your order.
We supply Q235B square hollow sections across a full dimension spectrum.
Square outer dimensions run from 40×40 mm up to 400×400 mm, with wall thickness ranging 2.5 mm‑16 mm.
Our regularly stocked square sizes cover:
40×40mm, 50×50mm, 60×60mm, 80×80mm, 100×100mm, 120×120mm,
150×150mm, 200×200mm, 250×250mm, 300×300mm, 350×350mm, 400×400mm.
Should your project call for alternative dimensions or wall gauges outside this scope, feel free to get in touch to review feasible options.
Standard supply lengths are:
6 meters
12 meters
For projects requiring longer members, custom lengths up to 21 meters can be supplied subject to production and transportation requirements.
Custom cutting services are also available to help reduce fabrication work and material waste at the project site.
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We offer multiple surface finishing options for Q235B square hollow sections to match different project conditions:
Black mill finish
Hot‑dip galvanized
Painted finish
Primer coating
Custom‑requested surface treatments
Galvanizing or coated finishes add extra corrosion resistance, which is highly recommended for components used outdoors or in corrosive working surroundings.
Q235B square hollow sections are versatile structural steel products, widely adopted in diverse conventional construction and industrial structural scenarios. Their stable performance and excellent processability make them a top choice for multiple common engineering applications.
Steel Framing Systems
These square tubes serve as core structural components for all types of general steel frame construction, delivering stable support and reliable structural performance for frame systems.
Light Load Structural Works
Ideal for light-duty structural projects that only require moderate load-bearing capacity, perfectly matching the stress demands of conventional lightweight building structures.
Workshop Construction
Commonly applied to factory and workshop construction, including main structural frames, auxiliary supports and various secondary steel parts to meet factory building structural needs.
General Building Projects
Widely used in various building engineering projects for structural frameworks, support systems and custom fabricated steel components, adapting to most conventional construction requirements.
Industrial Equipment Supports
The tubes can be freely cut and processed to manufacture custom support frames, fixing brackets and other supporting parts for different industrial equipment, with strong practicality for on-site industrial layout.
Symmetrical Square Profile
Its balanced square geometry delivers solid structural stability, while keeping cutting and fabrication work straightforward.
Comprehensive Size Range
Available across 40×40 mm up to 400×400 mm, covering diverse structural design and project demands.
Variable Wall Thickness Options
Wall thickness spans 2.5 mm to 16 mm, so customers can pick the proper section matching their specific load‑case needs.
Good Processing Performance
Q235B square hollow sections handle cutting, drilling and welding well, making it simple to produce custom‑built structural parts.
Flexible Length Options
Besides standard mill lengths of 6 m and 12 m, extended custom lengths are available upon negotiation.
Economical Structural Choice
For regular steel frames and light‑load structures, Q235B SHS offers a practical, budget‑friendly steel solution.
Royal Steel Group carries out quality checks at different stages, from production through to shipment.
Our inspection scope typically includes:
Chemical composition analysis
Yield strength
Tensile strength
Elongation property
Outer dimensional check
Wall thickness measurement
Length verification
Straightness tolerance
Weld integrity (for welded sections)
Mill Test Certificates (MTC) will be issued as specified in your purchase order.
If required by clients or project specifications, we are also able to coordinate third‑party inspection services.
Broad Product Portfolio
We carry a full selection of sizes, wall thickness options and structural steel profiles to support various construction‑related projects.
Solid Export Background
Proven hands‑on experience in global steel supply and cross‑border export logistics management.
Complete Document Support
We can prepare MTC, packing list, commercial invoice, Certificate of Origin and third‑party inspection paperwork in line with your order terms.
Value‑Added Custom Services
Custom cut‑to‑length and other secondary processing solutions are available upon discussion.
Project‑Focused Support
Technical specs, packaging standards and shipping arrangements can all be adjusted to fit your specific project conditions.
Q235B square hollow sections are firmly bundled for overseas shipments. This minimizes shifting during transit and helps avoid surface scratches or damage from loading‑unloading operations.
Our standard export packaging covers:
Steel strapping for secure bundling
Protective wrapping layers
Waterproof materials, applied where necessary
Clear bundle marking
Labels indicating size and quantity
Shipping solutions such as container loading or bulk vessel transport can be arranged. Final transport mode is determined by product dimensions, order volume and destination port.
1. What is Q235B SHS?
Q235B SHS refers to square hollow section structural steel tubes made from Q235B carbon steel. All products are manufactured in strict accordance with the national standard GB/T 6728-2017 to ensure stable and reliable structural performance.
2. What sizes do you offer?
We cover a comprehensive size range for square sections. The outer dimension ranges from 40×40mm to 400×400mm, while wall thickness options vary from 2.5mm to 16mm to suit different usage scenarios.
3. What is the yield strength of Q235B SHS?
Complying with standard specifications, this steel grade features a minimum yield strength of 235 MPa, meeting the basic load-bearing demands of conventional structural engineering.
4. What about its tensile strength?
The guaranteed minimum tensile strength of Q235B square hollow sections is 375 MPa, delivering dependable mechanical performance for general construction use.
5. What length options are available?
Our standard factory lengths are 6 meters and 12 meters for regular orders. To accommodate bespoke project designs, we also support custom-length processing, with a maximum customizable length of 21 meters.
6. What are the main application scenarios?
This type of square steel tube is widely utilized in general steel frame fabrication, light-load structural engineering, workshop construction, structural support systems and various conventional building projects.
7. Is galvanization available for Q235B SHS?
Absolutely. We provide hot-dip galvanized finishing for Q235B SHS upon request. This treatment effectively enhances corrosion resistance, making the tubes suitable for outdoor and harsh working environments.
8. Can you supply Mill Test Certificates?
Yes, we can provide official Mill Test Certificates (MTC). The documents will be issued strictly in line with product standards and specific order terms to support customer inspection and project acceptance.
ROYAL GROUP
Address
Kangsheng development industry zone,
Wuqing district, Tianjin city, China.
Phone
Hours
Monday-Sunday: 24-hour Service
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