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Q420B SHS Square Hollow Section Steel Tube GB/T 6728-2017 High-Strength Structural Steel Tube 60×60-350×350mm
Q420B SHS Square Hollow Section Steel Tube
Fabricated under GB/T 6728‑2017, our Q420B square hollow section (SHS) belongs to the high‑strength structural steel tube family. It achieves minimum 420 MPa yield strength and 520 MPa tensile strength, making it a practical choice for engineering projects calling for enhanced structural integrity and load‑carrying capacity.
We stock square profiles spanning 60×60 mm through 350×350 mm, with wall thickness options from 3.0 mm to 14 mm. Standard mill lengths sit at 6 m and 12 m, and custom‑cut lengths up to 21 m are offered to match individual project needs.
This Q420B SHS works well for high‑strength engineering builds, heavy‑duty structural frames, industrial plant builds and other rigorous steel construction scenarios.
| Item | Specification |
| Product | Q420B SHS Square Hollow Section |
| Steel Grade | Q420B |
| Standard | GB/T 6728-2017 |
| Shape | Square |
| Size Range | 60×60–350×350mm |
| Wall Thickness | 3.0–14mm |
| Minimum Yield Strength | ≥420 MPa |
| Tensile Strength | ≥520 MPa |
| Standard Length | 6m, 12m |
| Maximum Length | Up to 21m |
| Surface | Black / Customized |
| Typical Application | High-strength engineering structures |
Q355B is a high‑strength structural steel grade frequently specified for heavy‑duty steel construction work.
It achieves a minimum yield strength of 355 MPa and tensile strength of 470 MPa. Outperforming common lower‑grade structural steels, Q355B fits well for projects subject to heavy structural loads.
Minimum Yield Strength: ≥355 MPa
Tensile Strength: ≥470 MPa
For full chemical composition and complete mechanical property data, please check against GB/T 6728‑2017 and the product mill test certificate.
Dimension range for Q420B square hollow section:
Square size: 60×60 mm – 350×350 mm
Wall thickness: 3.0‑14 mm
These are among our most regularly specified sizes:
60×60 mm, 80×80 mm, 100×100 mm, 120×120 mm, 150×150 mm,
180×180 mm, 200×200 mm, 250×250 mm, 300×300 mm, 350×350 mm
Final availability of exact sizes and wall thickness is subject to your project requirements and production feasibility. Kindly double‑check before ordering.
Standard supply lengths for Q420B SHS are 6 m and 12 m.
For qualified projects, custom‑cut lengths up to 21 m are available upon request.
We also provide a range of supplementary processing services:
Cutting
Drilling
Hole punching
Welding
Drawing‑based custom fabrication
These custom processing options help minimise on‑site fabrication work and boost overall installation efficiency on‑site.
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We offer multiple surface finishing alternatives for Q420B square hollow sections to match varying‑project operating conditions:
Black mill finish
Hot‑dip galvanized
Solid painted finish
Primer‑coated
Custom‑formulated coatings on request
For outdoor deployment or locations with corrosive conditions, galvanized or coated finishes deliver extra corrosion resistance for Q420B SHS components.
High‑Strength Engineering Structures
Q420B square hollow sections fit structural projects demanding enhanced strength and reliable load‑carrying performance.
Heavy‑Duty Steel Frames
This high‑strength hollow profile works well for main structural frames and load‑bearing parts.
Industrial Structures
Typical deployment covers a wide range of industrial‑grade builds:
Industrial buildings
Heavy‑duty workshop facilities
Engineering‑related installations
Equipment supporting structures
Structural working platforms
Large‑scale steel frameworks
Heavy‑load support assemblies
Structural Columns and Bracing
Based on project design drawings, these square hollow sections can be utilised for columns, bracing and other engineered structural components.
High Mechanical Strength
Boasting a 420 MPa minimum yield strength, Q420B delivers a robust high‑strength solution for structurally‑demanding projects.
Efficient Square Profile Design
Its closed square geometry brings sound structural efficiency while offering good workability for fabrication jobs.
Broad Size Selection
Dimension coverage spanning 60×60 mm to 350×350 mm grants great adaptability across diverse engineering needs.
Versatile Wall Thickness Options
Wall thickness ranging from 3.0 mm up to 14 mm enables proper section selection matched against actual structural loads and design constraints.
Extended‑Length Supply Capability
Stock lengths of 6 m and 12 m come as standard. Custom lengths reaching 21 m can be arranged, subject to manufacturing and transport limits.
Proven for Engineering‑Grade Builds
Q420B square hollow sections perform exceptionally well for high‑strength engineering works and heavy‑duty steel construction.
Rigorous quality checks run through the whole manufacturing process, with final inspections carried out prior to dispatch.
Inspection items cover the following key aspects:
Chemical composition
Yield strength
Tensile strength
Elongation performance
Outer dimensional tolerance
Wall thickness
Product length
Straightness
Weld integrity (for welded sections)
Mill Test Certificates (MTC) will be issued in line with agreed product standards and order‑specific terms.
Upon client or project demand, third‑party inspection services can also be organised.
High‑Strength Structural Steel
Q420B square hollow sections deliver robust high‑strength performance for challenging engineering‑grade structures.
Comprehensive Product Portfolio
We supply square hollow sections spanning 60×60 mm to 350×350 mm, with wall thickness ranging from 3.0 mm to 14 mm.
Custom Fabrication Services
Cutting, drilling and custom fabrication work can be completed based on clients’ technical drawings.
Full‑Set Quality Documentation
We furnish MTC, Certificate of Origin, packing list, commercial invoice and inspection reports as required by each individual order.
End‑to‑End Export Support
Our professional service covers manufacturing, quality inspection, export‑grade packaging and global shipping arrangements.
For export shipments, Q355B SHS is typically bundled and fastened with steel straps. This reduces shifting during loading, unloading and transit.
Our export‑grade packaging covers the following options:
Steel strapping
Waterproof shielding
Protective wrapping
Bundle marking
Shipping marks
Size & quantity labels
Transport solutions can be arranged via container, bulk carrier or other suitable shipping modes, based on product dimensions, order volume and final destination.
1. What is Q420B SHS?
Q420B SHS refers to high-strength square hollow structural steel sections, produced in strict accordance with the national standard GB/T 6728-2017.
2. What is the yield strength of Q420B SHS?
This steel grade features a minimum yield strength of 420 MPa, delivering outstanding structural load-bearing performance.
3. What is the tensile strength of Q420B SHS?
Its minimum tensile strength is rated at 520 MPa, ensuring stable and reliable mechanical performance in complex construction scenarios.
4. What size options do you offer for Q420B SHS?
We provide a full range of specifications, with square section sizes ranging from 60×60mm to 350×350mm, and wall thicknesses covering 3.0mm to 14mm to meet diverse design needs.
5. What standard and custom lengths are available?
Our standard factory lengths are 6 meters and 12 meters. To accommodate special project demands, we also support customized cutting lengths up to 21 meters, subject to production conditions and transportation feasibility.
6. What are the typical application scenarios for Q420B SHS?
It is widely applied in high-strength engineering construction, heavy-load steel frame structures, building structural columns, support bracing systems and various industrial facility structures.
7. Is hot-dip galvanizing treatment available?
Absolutely. We offer hot-dip galvanizing surface treatment for Q420B SHS, which effectively enhances corrosion resistance, making the steel tubes suitable for outdoor and corrosive working environments.
8. Can you provide Mill Test Certificates (MTC)?
Yes. We can supply official Mill Test Certificates that fully comply with industry standards and customer order specifications, to guarantee product quality traceability.
ROYAL GROUP
Address
Kangsheng development industry zone,
Wuqing district, Tianjin city, China.
Phone
Hours
Monday-Sunday: 24-hour Service
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