Spiral strand cables are precision-engineered steel wire ropes designed for superior structural integrity, high load-bearing capacity, and low stretch performance. They are constructed by helically winding cold-drawn galvanized or stainless steel wires in one or more layers around a central core. This design delivers outstanding tensile strength, excellent corrosion resistance, and long-term durability, making them ideal for demanding static and semi-static applications.

Structure & Design

Spiral strand cables are composed of multiple layers of high-tensile steel wires helically wound around a central core wire. This geometric arrangement provides excellent axial alignment, uniform stress distribution, and high strength.

Basic Components:

1. Core Wire (Center Wire):

   • The innermost wire that serves as the backbone of the cable.

   • Typically the same diameter and material as the outer wires.

2. First Layer of Helical Wires:

   • Wound tightly around the core in a single helical direction (either right-hand or left-hand lay).

   • This 1+6 structure (one core + six outer wires) forms the simplest spiral strand.

3. Multiple Layers (Optional):

   • For increased strength and larger diameters, additional layers of wires are wound concentrically over the first layer.

   • Each layer is laid in the same helical direction to maintain strand stability.

4. Wire Material and Finish:

   • Usually made of cold-drawn high-carbon steel, galvanized steel, or stainless steel.

   • Surface finishes may include zinc, aluminum-zinc alloy, or polymer coatings for enhanced corrosion resistance.

Typical Construction Patterns:

• 1×7 (1+6) – Basic structure for small-diameter strands.

• 1×19 (1+6+12) – Common for medium-duty structural applications.

• 1×37 ,  1X61, 1X91 or higher – Used for large-span bridges, towers, and other heavy-load structures.

Stranding Direction:

• Spiral strand cables are usually laid in a single uniform direction (e.g., right-hand lay), unlike regular ropes where layers alternate directions to reduce torque.

• The consistent lay direction ensures better performance under tension in static systems.

Key Features

• High strength-to-weight ratio

• Low elongation under load

• Excellent fatigue and corrosion resistance

• Precision-manufactured for dimensional stability

• Available in galvanized, aluminized, or stainless steel

Common Applications

• Bridge suspension and stay cables

• Guy wires and mast stays

• Structural support in stadiums, towers, and roofs

• Cable barriers and railings

• Offshore mooring and anchor lines

• Wind turbine supports

• Crane pendants and heavy lifting systems

Customization & Standards

Spiral strand cables can be manufactured to meet international standards such as EN 12385, ASTM A586, or BS 183, with options for:

• Diameter ranges from a few millimeters to over 100mm

• Zinc/aluminum coatings for long-term corrosion protection

• End terminations (socketing, swaging, etc.)

• Tensile grades from 1,570 MPa to 1,960 MPa or higher