Why does TSF reach better results than phosphated wire?

Because TSF reduces the friction coefficient during the cold heading process keeping the lubricant on the wire during all extrusion steps where the phosphated wire has already lost some of its qualities.

Comparison between phosphated wire and TSF wire:

Key factors to obtain lower friction coefficients than phosphated wires:

a) Carrier: With TSF  a mechanical rugosity of Ra>2µm is reached, which is enough to put in the lubricant.

b) Lubricant TSF: The size of the lubricant particles is key to enable them to remain inside the carrier.

c) Application of the Lubricant: The high pressure applied during the skin-pass (final wire drawing) permits to put the lubricant into the mechanical carrier.