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ASTM A500 Grade B / Grade C & Q355B Weld Steel Square Tube for Structural Building Construction | Carbon Steel Hollow Section Supplier
| Item | Specification |
| Product Name | ASTM A500 Grade B / Grade C & Q355B Welded Steel Square Tube |
| Shape | Square Hollow Section (SHS) |
| Material Grade | ASTM A500 Grade B, ASTM A500 Grade C, Q355B |
| Standard | ASTM A500, GB/T 6728, EN10219 (Optional) |
| Outer Size | 20×20mm – 500×500mm |
| Wall Thickness | 0.8mm – 20mm |
| Length | 5.8m, 6m, 12m or Customized |
| Manufacturing Process | Cold Formed, Hot Rolled, ERW Welded |
| Surface Finish | Black, Oiled, Painted, Hot-Dip Galvanized |
| Zinc Coating | 40–600g/m² (for galvanized tubes) |
| Certification | ISO 9001, Mill Test Certificate (MTC) |
| Trade Terms | FOB, CFR, CIF, EXW |
| ASTM A500 Grade B / Grade C & Q355B Square Steel Pipe – Chemical Composition by Grade | |||
| Element | ASTM A500 Grade B | ASTM A500 Grade C | Q355B |
| Carbon (C) | Max 0.26 | Max 0.23 | Max 0.24 |
| Manganese (Mn) | Max 1.35 | Max 1.35 | Max 1.60 |
| Phosphorus (P) | Max 0.035 | Max 0.035 | Max 0.035 |
| Sulfur (S) | Max 0.035 | Max 0.035 | Max 0.035 |
| Silicon (Si) | — | — | Max 0.55 |
| Copper (Cu) | Min 0.20* | Min 0.20* | — |
| Nickel (Ni) | Optional | Optional | Optional |
| Chromium (Cr) | Optional | Optional | Optional |
| Vanadium (V) | — | — | Max 0.15 |
| Niobium (Nb) | — | — | Max 0.07 |
| Titanium (Ti) | — | — | Max 0.20 |
| ASTM A500 Grade B / Grade C & Q355B Square Steel Pipe – Mechanical Properties | ||
| Grade | Yield Strength | Tensile Strength |
| ASTM A500 Grade B | ≥ 315 MPa | ≥ 400 MPa |
| ASTM A500 Grade C | ≥ 345 MPa | ≥ 427 MPa |
| Q355B | ≥ 355 MPa | 470–630 MPa |
High Structural Strength
Made of ASTM A500 B/C and Q355B steel. Great yield strength and load capacity for heavy structural use.
Excellent Weldability
Low carbon content enables easy welding and processing, cutting on-site time and costs.
Precise Dimensions
Strict QC guarantees accurate size, straightness and uniform wall thickness.
Corrosion Protection
Multiple finishes: black steel, anti-rust oil, paint and hot-dip galvanized.
Cost-Effective
Welded square tubes deliver solid performance at a more competitive price.
ASTM steel pipe refers to carbon steel pipe used in oil and gas transmission systems. It is also used to transport other fluids such as steam, water, and mud.
The ASTM STEEL PIPE specification covers both welded and seamless fabrication types.
Welded Types: ERW Pipe
Welding Compliance and Inspection for ASTM A53 Square Steel Pipe
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Welding Method: ERW (Electric Resistance Welding)
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Standards Compliance: Fully conforms to ASTM A53 welding process requirements
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Weld Quality: 100% of welds pass non-destructive testing (NDT)
Note: ERW welding ensures strong, uniform seams, meeting structural performance and safety standards for columns, trusses, and other load-bearing applications.
| Application Scenario | Specification (Size × Thickness) |
| Construction & Steel Structure | 50 × 50 × 3.0 mm |
| 75 × 75 × 3.0 mm | |
| 100 × 100 × 4.0 mm | |
| 150 × 150 × 6.0 mm | |
| 200 × 200 × 8.0 mm | |
| Warehouse & Workshop Buildings | 100 × 100 × 4.0–6.0 mm |
| 150 × 150 × 6.0–10.0 mm | |
| 200 × 200 × 8.0–12.0 mm | |
| Infrastructure & Heavy Structures | 250 × 250 × 10.0 mm |
| 300 × 300 × 12.0 mm | |
| 400 × 400 × 16.0 mm | |
| 500 × 500 × 20.0 mm | |
| Solar Mounting & Fence Systems | 40 × 40 × 2.0 mm |
| 50 × 50 × 2.5 mm | |
| 60 × 60 × 3.0 mm | |
| General Technical Parameters | |
| Available Standard | ASTM A500 Grade B, ASTM A500 Grade C, Q355B |
| Length | 5.8m, 6m, 11.8m, 12m or Customized |
| Surface Treatment | Black, Oiled, Painted, Hot-Dip Galvanized |
| Processing Service | Cutting, Drilling, Welding, Punching, Galvanizing, Custom Fabrication Available |
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ASTM A500 Grade B/C & Q355B Square Steel Pipes
Available surface treatments:
Black Bare Steel
Anti-rust oiled finish
Red oxide primer coating
Hot-dip galvanized
Epoxy coating
Custom protective coatings
ASTM A500 Grade B Grade C & Q355B Weld Steel Square Tube Application
| Feature | Description |
| High Structural Strength | Made of ASTM A500 B/C & Q355B steel, great yield strength and load capacity for heavy structural use |
| Excellent Weldability | Low carbon material for easy welding and fabrication, saving time and costs |
| Precise Dimensions | Strict QC ensures accurate size, straightness and uniform wall thickness |
| Corrosion Protection | Available in black steel, anti-rust oil, paint and hot-dip galvanized finishes |
| Cost-Effective | Reliable performance with competitive pricing |
Royal Steel Group is a professional supplier of structural steel tubes and hollow profiles with extensive export experience, operating in North America, South America, the Middle East, Southeast Asia, Africa, and Europe. We offer rigorous quality control, competitive pricing, customized processing services, and reliable global logistics support to help our clients complete construction and infrastructure projects efficiently and economically.
All square steel tubes are firmly secured with steel strapping and waterproof packaging to avoid dampness and rust during transport. Custom export packaging is available for containers, bulk cargo and international project orders.
1. What steel grades do you offer for square tubes?
We mainly supply ASTM A500 Grade B, ASTM A500 Grade C and Q355B square steel tubes to meet most global construction and infrastructure standards. We also support other common grades like Q235B, S275JR and S355J2H on special request, fully matching different regional project requirements.
2. What size and customization options are available?
Our square tube coverage ranges from 20×20mm up to 500×500mm, with wall thicknesses from 0.8mm to 20mm. Beyond standard sizes, we accept fully custom dimensions. We also provide one-stop processing including cutting to custom lengths, drilling, punching, welding and beveling, tailored exactly to your drawings and project needs.
3. What quality documents and certifications can you provide?
We support full quality verification for all export orders. We can officially issue Mill Test Certificates (MTC), ISO 9001 certification, material and dimensional inspection reports. Third-party inspection certificates are also available upon your request to satisfy international project audit standards.
4. What is your actual production and delivery lead time?
For regular standard sizes in stock, we can finish shipment within 7 to 15 days after order confirmation. For customized specifications or large-volume project orders, we will confirm a reasonable production schedule in advance to ensure stable and on-time delivery for your overseas projects.
5. What surface treatments and export packaging do you provide?
We have multiple mature surface finish options: black bare steel, anti-rust oil coating, red oxide primer, hot-dip galvanizing and epoxy coating, plus custom protective coatings for special usage scenarios. All products are firmly strapped with steel bands and wrapped with waterproof materials to resist moisture and corrosion during long-distance sea transportation. We also offer exclusive custom export packaging for container shipments, bulk cargo and global project
Contact Details
Address
Kangsheng development industry zone,
Wuqing district, Tianjin city, China.
Phone
Hours
Monday-Sunday: 24-hour Service
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