What Is 7x7 Galvanized Steel Wire Rope?

7x7 wire rope is a versatile and widely used rope construction. The name tells you exactly how it is constructed. There are 7 strands, and each strand is made up of 7 individual wires twisted together. These strands are then laid around a central core – wire in this case to form the finished rope.

The galvanised finish is applied by coating each wire in a layer of zinc before the rope is manufactured. This zinc barrier protects the steel underneath from moisture, salt, and other corrosive elements, significantly extending the life of the rope in harsh or outdoor environments.

Where is 7x7 galvanized rope used?

The galvanization process makes the rope useable in many environments, both indoors and out. The 7x7 construction provides more limited flexibility than ropes with more wires, thus would not be a good rope for winches and sheaving tasks due to the need for constant bending. Typical uses for the 7x7 galvanized rope include aircraft cables, balustrades, cable railings, lifting slings and control cables. We supply the 7x7 rope regularly to the aviation industry.

Breaking Loads, mass and Stretch

The 7x7 rope construction has a minimum breaking force that is calculated as K=0.388 and will depend on the rope diameter. For example a 10mm rope would be 0,388 x 10² which gives you a minimum breaking force of 38.8 kN (kilo-newtons).

After the first load, the wires bed down and produce a small amount of stretch, subsequent loading may also result in elastic stretch which is not an exact science with wire ropes but is typically estimated using Hookes law where stress is proportional to strain.

The nominal length mass factor will determine the theoretical mass of a unit length of rope. Thus M (mass) = W (length) x d² (diameter). The 7x7 uses W=0.384 to calculate the nominal mass.

More Wire Rope Constructions

Lifting Gear Direct can supply many wire rope constructions in both galvanized and stainless steel. We can also create custom rope assemblies to suit your requirements and offer a wide range of end terminations which can be permanently pressed to your chosen rope.