Rectangular Tube Galvanized square Tube Iron Seamless square Tube

Rectangular Galvanized Tubes, Galvanized Square Tubes, and Seamless Square Iron Tubes are three common structural and fluid-transmission components in construction, machinery, and municipal engineering. Each type combines unique structural forms (rectangular/square) with material/process advantages (galvanization/seamless), and their core features are detailed as follows:

1. Rectangular Galvanized Tube

• Superior Corrosion Resistance via Hot-Dip Galvanization
  Coated with a dual-layer zinc structure (zinc-iron alloy layer + pure zinc layer, thickness ≥85μm) through hot-dip galvanization. This coating fully covers the tube’s inner/outer walls, edges, and welds, isolating moisture, oxygen, and corrosive media (e.g., salt spray, industrial fumes). It maintains structural integrity for 30–50 years in outdoor/ humid environments, 5–8 times longer than ungalvanized rectangular tubes.
• Optimized Rectangular Cross-Section for Asymmetric Loads
  The rectangular shape provides higher lateral bending stiffness and torsional resistance than circular tubes of the same weight—ideal for applications with uneven stress (e.g., building curtain wall keels, billboard frames, automotive chassis beams). For example, a 60x120mm galvanized rectangular tube (wall thickness 3mm) has a 40% higher bending moment capacity in the longer axis direction than a 80mm-diameter galvanized round tube of the same weight.
• High Dimensional Precision & Easy Assembly
  Strict tolerance control: length tolerance ±2mm/m, side length tolerance ±0.3mm–±0.5mm, and wall thickness uniformity deviation ≤5%. Complies with standards like EN 10219 or ASTM A500, ensuring seamless compatibility with standard connectors (bolts, brackets). The flat surfaces of the rectangular cross-section simplify welding and bolting to other components (e.g., steel plates, support legs).
• Good Workability & Versatility
  Made of low-carbon steel (e.g., Q235B), it supports on-site cutting, bending, and drilling without cracking. Suitable for diverse projects: municipal railings (utilizing corrosion resistance), furniture frames (relying on shape adaptability), and industrial conveyor supports (leveraging load-bearing capacity).

2. Galvanized Square Tube

• Uniform Corrosion Protection & Longevity
  Hot-dip galvanized versions feature a thick zinc layer (≥85μm) with strong adhesion (metallurgical bonding with steel), resisting peeling from impact or friction. Electro-galvanized versions (zinc layer ≥15μm) offer cost-effective corrosion resistance for indoor/light-duty scenarios (e.g., display racks). Both types avoid rust-related structural failure, reducing maintenance costs.
• Symmetric Square Cross-Section for Balanced Loads
  The square shape distributes stress evenly across all four sides, making it ideal for symmetric load-bearing components: building columns, shelf uprights, and outdoor pergola frames. A 100x100mm galvanized square tube (wall thickness 4mm) can withstand a compressive load of over 120kN, meeting the needs of medium-weight structural supports.
• Smooth Surface & Aesthetic Appeal
  The galvanized surface is smooth (Ra ≤12.5μm) with a uniform silver-gray finish, eliminating the need for additional painting in visible applications (e.g., decorative railings, storefront frames). The square form also creates clean, modern lines, enhancing the visual effect of architectural or decorative projects.
• Cost-Effective & High Production Efficiency
  Manufactured via ERW (Electric Resistance Welding) or seamless processes followed by galvanization, with high production speed (up to 50m/min for small-caliber tubes). The standardized square dimensions reduce material waste, making it a more economical choice than custom-shaped profiles for large-volume projects.

Structural engineering (buildings, bridges, towers)

Machinery manufacturing

Steel frameworks and fabrication

Transportation equipment

Furniture and architectural projects

Fencing, gates, and support columns