Zn-5Al Mischmetal Coated Steel Strand 1x7 3.0-8.0mm Long Life Corrosion Cable

Zn-5Al mischmetal coated steel strand, 1x7, 3.0mm to 8.0mm, for tension cable that has to survive salt air and industrial atmosphere without regular attention.

Plain zinc coating protects steel sacrificially, but it consumes itself doing so. Add about five percent aluminium and a trace of mischmetal to the coating and the corrosion product that forms at a damage point is different: it is denser, it stays in place, and it keeps the anodic reaction local instead of spreading along the wire.

In practice that means a zinc aluminium coated strand often delivers two to three times the service life of a plain galvanized strand of the same coating mass. We first ran this coating for a coastal vineyard trellis job where the plain galvanized wire was failing at the wire to post contact point in under four years. The coated strand in the same rows is still sound, which is the kind of evidence that matters more than a data sheet claim.

• Two to three times the corrosion life: The alloy coating protects longer at grab points, cut ends and clamp contacts, which are the three places plain zinc always fails first on a tension cable.
• Aluminium bearing corrosion product stays put: The protective layer forms as a stable, dense film rather than a loose white corrosion product that washes away and exposes fresh steel to the next rain.
• Bare cut ends survive longer: A cut end is always the weak point. On the alloy coated strand the exposed steel at the cut stays bright far longer, which matters on site cut installations nobody re-coats afterwards.
• 1x7 balance of strength and give: Seven wires per strand gives a firm strand that tensions cleanly and resists kinking on a small former, while still wrapping a post or end anchor without taking a permanent bend.
• Suited to agricultural and coastal tension work: Vineyard and orchard trellis, hop wire, shade and netting support, coastal fence and barrier lines, all duties where the wire is in constant contact with plants, soil or salt.
• Coating mass stated and measured: Between 200 and 260 grams per square metre, measured by stripped weight per lot. Alloy coatings look similar to plain zinc, so the certificate is the only way a buyer can tell what was actually applied.

The biggest single use is agricultural tension wire: vineyard and orchard trellis, hop and berry support, and netting anchor lines where the wire is expected to last twenty seasons without replacement. Coastal fence and barrier lines are the second main use.

It also suits industrial sites with sulphur or chloride in the air, and any installation where a maintenance visit costs more than the wire itself, which is usually the case on remote farm and coastal sites.

• Vineyard and orchard trellis tension wire
• Hop, berry and netting support lines
• Coastal fence and barrier cable
• Industrial atmosphere static tension lines
• Remote site tensioning where access is costly

Coating mass is measured by stripped weight on samples from both ends of each lot. We also run a salt spray comparison against plain galvanized strand from the same wire base, and the hours to first red rust are logged, so the claim on the page is backed by a file rather than a brochure sentence.

Breaking load, elongation and torsion are tested per lot, and the strand is inspected for coating skips at wire crossover. Skips are the defect that kills alloy coated strand early, and they are invisible on a visual check of the outside of the strand.

Wooden reels or coils of 500m to 3000m, VCI wrapped and strapped. For trellis work we can supply coils with both ends served and a tensioning grip fitted, which saves the crew from fighting a springy coil end on a windy hillside.