Overview
PPD wire is wire rod that has been acid-pickled to remove mill scale, coated with zinc phosphate and a lubricant carrier, and then drawn to the finished size. The phosphate layer bonds the drawing lubricant to the steel, so the wire arrives at the header with a surface that reduces die wear and lets the metal flow in the tooling.
At Indisteel, drawing is done on ASSOMAC inverted vertical drawing (IVD) machines covering finished diameters from 2.80 mm to 30 mm. Size is held with micrometer checks at start-up and through the run, and coating weight is verified in our lab.
Applications
- Standard and high-tensile fasteners in the as-drawn condition
- Screws, studs and pins for automotive and construction
- Cold-forged engineering parts where a phosphate surface is specified
- Customers who anneal in-house and need drawn, coated feed wire
Frequently Asked
Why is the wire phosphated before drawing?
Zinc phosphate forms a crystalline layer that holds lubricant on the wire surface. It lowers friction in the drawing die and in the customer's heading tools, reduces galling and helps the wire fill complex die shapes.
What is the difference between PPD and hard bright (HB) wire?
Both follow the same pickling, phosphating and drawing route. PPD wire is specified for cold heading with controlled drawing reduction and surface, while HB wire is supplied as a hard-drawn coil for nails, rivets, wire forms and general engineering.