ASTM A475 Class B Galvanized Steel Strand 1x7 6-10mm Marine Grade Guy Wire

ASTM A475 Class B galvanized steel strand, 1x7, 6mm to 10mm, certified to a named standard rather than a general description.

When a specification names ASTM A475 Class B, it is naming a coating mass and a set of mechanical requirements, not just a colour. Class B sits between the standard Class A and the extra heavy Class C, and it is the class most often specified for outdoor and marine-adjacent work where Class A has proved too thin but Class C is not justified on cost.

The value of buying to a named standard is that the inspector has something to check. We measure coating mass by stripped weight, test breaking load and elongation per lot, and issue a certificate that references the standard and the class. If a project calls for A475 Class B and the delivery says only galvanized, the buyer has no way to prove what arrived.

• Coating mass around 305 grams per square metre: Roughly forty percent more zinc than a standard Class A coating, which typically means several additional years before first rust in a marine-adjacent atmosphere.
• Certificate references the standard and class: The test report states ASTM A475 Class B, the measured coating mass and the tested breaking load. That is what an inspector needs, and it is what most mills leave out.
• 1x7 construction for drum and clamp work: Seven wires give a strand that spools on a small drum, wraps a thimble neatly and grips well in a standard guy clamp, which keeps the hardware simple.
• Grades 1370 and 1570 available: Both common strength grades are stocked in 6mm to 10mm. If the design calls for 1570, you get 1570 with a certificate, not a 1370 strand described as high strength.
• Handles site abuse: Class B coating tolerates the scuffing that happens when a guy is pulled through vegetation or dragged over a concrete edge. Thin coatings lose protection at exactly those points.
• Consistent lay and roundness: Lay length is checked at three points per reel and the strand is measured for ovality. A round strand loads evenly in the clamp, which prevents the classic slippage failure on guy terminations.

The main use is outdoor and marine-adjacent guy work: marina poles and lighting masts, harbour fence and barrier anchoring, and industrial guy sets on stacks and conveyors near the coast.

It is also specified for general outdoor tensioning where the buyer wants a documented coating class, including agricultural structures, sign gantries and overhead line stays in industrial atmospheres.

• Marina pole and lighting mast guys
• Harbour fence and barrier anchor strand
• Industrial guy sets on stacks and conveyors
• Sign gantry and overhead line stays
• Agricultural structure tensioning

Coating mass is determined by stripping a measured length in inhibited acid and weighing the residue, on samples from both ends of every lot. Class B is only claimed when the measured value is above the minimum, never when it is close and averaged.

Breaking load, elongation and torsion tests are completed per lot with the fracture position recorded. Reels are inspected over their full length for broken wires, proud wires and coating skips, and any reel with a skip in a high stress area is cut back before shipping.

Wooden or iron reels of 500m to 3000m, VCI wrapped and strapped, marked with size, length, standard, coating class, measured zinc mass and lot number. Cut lengths are served at both ends and bundled so short guy sets do not arrive as a tangle of loose ends.