Square Rectangular Tubes

Your Ultimate Guide to Choosing High-Performance Steel Hollow Sections

As a leading manufacturer of steel square and rectangular tubes, we empower global industries with precision-engineered hollow structural sections (HSS). This comprehensive guide answers top customer queries like:
“What are square tubes used for in construction?”
“Which material grades meet ASTM/EN standards?”
“How to select the right size for machinery frames?”

Discover why our square and rectangular tubes are trusted by architects, engineers, and OEMs across 30+ countries.

1. Materials & Manufacturing: Building Blocks of Durability
(Keywords: ASTM A500 square tubing, galvanized rectangular steel tubes, cold-formed hollow sections)
A. Common Materials
Carbon Steel (ASTM A500 Gr B/C):
Grades: Q235, S235JR, SS400
Features: Cost-effective, weldable, ideal for structural frameworks.
Stainless Steel (ASTM A554):
Grades: 304, 316L
Features: Corrosion-resistant for food processing and marine environments.
Galvanized Steel (EN 10346):
Hot-dip galvanized (Zinc coating: 60-100 g/m²)
Features: Rust-proof for outdoor signage and agricultural equipment.
B. Production Methods
ERW (Electric Resistance Welded): High-speed forming for uniform thickness (0.8–6.0 mm).
Cold-Drawn: Tight tolerances (±0.1 mm) for precision machinery parts.
Hot-Finished: Seamless tubes for high-pressure applications (API 5L).

2. Global Standards & Certifications
(Keywords: EN 10219 rectangular tubes, JIS G3466 square pipes, ISO 657 hollow sections)

Our tubes comply with ISO 9001, CE Marking, and RoHS for global project approvals.

3. Popular Sizes & Customization Capabilities
(Keywords: standard square tube sizes, custom rectangular tubing dimensions)
A. Common Square Tube Sizes (mm/inch)
Small: 20×20×1.5 (0.8″×0.8″×16 gauge) – Handrails, furniture
Medium: 50×50×3.0 (2″×2″×11 gauge) – Machine frames, solar racks
Large: 150×150×6.0 (6″×6″×1/4″) – Warehouse columns, bridge supports
B. Rectangular Tube Dimensions
Aspect Ratios: 1:1.5 to 1:3 (e.g., 40×60×2.5 mm for conveyor systems)
Wall Thickness: 0.7–12.7 mm (22 gauge–1/2″)
Custom Options:
Non-standard sizes (e.g., 37×25×2.0 mm for automotive exhausts)
Slotted, perforated, or radius-corner designs
Pre-painted (RAL colors) or powder-coated finishes

4. Top 10 Industrial Applications of Square/Rectangular Tubes
(Keywords: uses of square steel tubes, rectangular hollow section construction)
1. Construction & Architecture
Structural Framing: Steel buildings, mezzanine floors (ASTM A500 Gr C)
Curtain Walls: Lightweight aluminum square tubes (6063-T5)
Staircases & Balustrades: Mirror-polished stainless steel tubes (316L)
2. Machinery & Automation
CNC Machine Frames: Stress-relieved cold-drawn tubes (±0.2 mm straightness)
Robotic Arms: High-strength rectangular tubes (EN 10219 S355J2H)
Conveyor Systems: Abrasion-resistant galvanized tubes (Z275 coating)
3. Transportation & Automotive
Trailer Chassis: Large rectangular tubes (200×100×6 mm, ASTM A1085)
Roll Cages: DOM (Drawn Over Mandrel) tubes with 360 MPa yield strength
EV Battery Frames: Laser-cut aluminum square tubes (6061-T6)
4. Energy & Infrastructure
Solar Mounting Systems: Zinc-coated tubes (40×40×2 mm, IEC 61730 compliant)
Wind Turbine Towers: Seamless square tubes for lattice sections (API 5L X60)
Oil & Gas Pipelines: ERW black steel tubes (API 5CT J55)

5. Furniture & Retail
Modular Shelving: Powder-coated square tubes (EPOXY/PVDF finishes)
Display Racks: Thin-wall ERW tubes (25×25×0.8 mm)
Outdoor Benches: Corten steel tubes with rustic patina

5. Technical Advantages Over Solid Bars & Other Profiles
(Keywords: hollow structural sections benefits, square tube vs I-beam)

6. Quality Assurance & Testing Protocols
(Keywords: square tube inspection, ultrasonic testing for HSS)
Our multi-stage QC process ensures:
Dimensional Accuracy: Laser measurement (±0.15 mm tolerance)
Weld Integrity: Eddy current testing (EN 10246-3)
Mechanical Properties: Tensile tests (ISO 6892-1), hardness checks (Rockwell B/C)
Surface Quality: Salt spray testing (ASTM B117) for galvanized tubes

7. FAQs: Solving Buyer Concerns
(Keywords: square tube load capacity, painting rectangular steel tubes)
Q1: Can square tubes replace RHS (Rectangular Hollow Sections) in load-bearing walls?
A: Yes, when matching equivalent cross-sectional area (e.g., 100×100×6 mm square tube ≈ 120×80×6 mm RHS).
Q2: How to prevent rust on ungalvanized square tubes?
A: Apply primer + polyurethane paint (DFT 120–150 μm) or use Corten weathering steel.
Q3: What’s the maximum span for 50×50×3 mm square tubes as shelving?
A: 1.8 meters under 200 kg UDL (consult our HSS Load Calculator).

8. Why Choose Us?
(Keywords: reliable square tube suppliers, custom hollow section manufacturers)
Global Certifications: ASTM, EN, JIS, and GB standards
Fast Turnaround: 15–20 days for 20ft/40ft container orders (FOB/CIF)
Value-Added Services:
Precision cutting (mitre, laser, or waterjet)
Threading, notching, and hole punching
Third-party inspection (SGS/BV)

Conclusion: Power Your Projects with Precision-Engineered Tubes
From skyscrapers to solar farms, square and rectangular tubes deliver unmatched strength-to-weight ratios and design versatility. Whether you need standard sizes or custom profiles, our solutions align with your technical, aesthetic, and budgetary goals.

Get Started Today!
Download our Square Tube Technical Handbook for load tables and CAD drawings, or [Request a Quote] for competitively priced ASTM/EN-compliant tubes.