Yingnai FRP square tube combines a closed hollow section with continuous fiberglass reinforcement for lightweight, corrosion-resistant structural applications. Its balanced geometry provides good bending and torsional stiffness for frames, handrails, supports and modular structures. Tube width, wall thickness, resin system, length, colour and connection details can be customized for different industrial environments.
| Item | Typical Technical Specification |
| Product Name | FRP Square Tube |
| Cross-Section | Closed square hollow pultruded profile |
| Typical Size Range | Outside width 20–250 mm; wall thickness 2.5–12 mm |
| Dimension Designation | Outside width × outside height × wall thickness |
| Standard Length | 6 m standard; 3–12 m can be supplied |
| Material System | Pultruded E-glass or ECR-glass reinforcement in an isophthalic polyester, vinyl ester or project-selected thermoset resin matrix |
| Mechanical Properties | Density 1.7–2.0 g/cm³; longitudinal tensile strength typically ≥200 MPa; longitudinal flexural strength typically ≥200 MPa; flexural modulus typically ≥17 GPa |
| Section Characteristics | Closed section provides good torsional stiffness and protects internal cables or fasteners |
| Jointing | Bolted plates, bonded inserts, FRP gussets or mechanical connectors |
| Typical Applications | Frames, handrails, equipment supports, fencing, platforms and modular structures |
| Inspection | Dimensional inspection, straightness, twist, cut length, surface condition, wall thickness, cure and Barcol hardness |
| Applicable Standards | ASTM D3917, ASTM D4385, ASTM D638, ASTM D790 and ASTM D2583 |
| Selected Standard Sizes | |||
| Profile Size | Unit Weight | Profile Size | Unit Weight |
| 120 × 120 × 5 mm | 4.10 kg/m | 100 × 100 × 5 mm | 3.70 kg/m |
| 100 × 100 × 2.7 mm | 2.20 kg/m | 80 × 80 × 3.5 mm | 2.00 kg/m |
| 70 × 70 × 4 mm | 1.95 kg/m | 60 × 60 × 5 mm | 2.05 kg/m |
| 50 × 50 × 5 mm | 1.62 kg/m | 50 × 50 × 4 mm | 1.40 kg/m |
| 40 × 40 × 4 mm | 1.04 kg/m | 40 × 40 × 3.5 mm | 1.00 kg/m |
| 40 × 40 × 2.7 mm | 0.83 kg/m | 30 × 30 × 3.1 mm | 0.653 kg/m |
| 25 × 25 × 5 mm | 0.76 kg/m | 250 × 250 × 10 mm | 18.20 kg/m |
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