For semi-finished products

Cold heading wire producer

e-phos - Surface coating

Complete devices for single- and multi-wire treatment for cold heading wire up to 30mm diameter

The e-phos surface coating process is suitable for:

  • the production of cold heading wire products
  • the drawing of steel wire

In the e-phos process, a firmly adhering, fine crystalline layer of zinc-calcium-phosphate crystals is deposited using DC current in an exposure time of approx. 2 seconds. Furthermore, this conversion layer can also be neutralised using various lubricants such as a lime milk suspension, soap or polymer.

Electrolytic phosphating

Patented surface coating with an especially 
developed zin-calcium-phosphate solution 


Wire surface after treatment with e-phos-process

Wire surface after treatment with e-phos-process

Thanks to the sophisticated drying technology, these wires can be further processed immediately after coating so that a short coating line or this size can be installed immediately upline of a drawing machine.

In view of the short footprint of the complete line (approx. 7,000 mm), the e-phos technology offers a high-quality alternative to borax coating which has been forbidden in line with the Reach Directive. In addition, the use of e-phos offers wire drawing shops (manufacturers of semi-finished products) the possibility of producing cold heading wire grades or wires with phosphated surface. In the past, several million euros had to be invested in a complex and environmentally harmful dip-pickling and coating line in order to do this. Furthermore, these plants included large fume extraction systems for acid vapours and corresponding neutralisation systems for the rinsing water. Not only the investment costs, but also the operating costs swallowed up huge amounts of money.

The e-phos technology eliminates wastes such as sewage or iron phosphate sludge whose disposal is correspondingly costly. The calculated process costs, including electricity, chemicals, etc. are in the order of 2 €/t.

EuroWire July 2011 "Continuous electrolytic processes for perfect wire surface"
Wire 09/2003 – Electrolytic zinc-phosphating of steel wire
Wire 01/2007 "Phosphate coatings on metal surfaces"

Special advantages of e-phos with regard to the traditional chemical phosphating:

  • Bigger adhessive strength of the layer caused by the fine crystall structure
  • Avoidance of waste water to neutralize does not require any permission by the government for the installation of e-phos-line.
  • No creation of iron-phosphate-sludge leads to: Avoidance of bath cleaning shifts, saving of about 40 % fresh chemicals and no disposal of sludge
  • Saving of heat energy caused by smaller bath volumes ( 3.000 ltr.) and lower bath tempera- tures at only 50 °C.
  • Low consumption of electrical power for the coating process, e.g. the costs for the coating of 8.8 to of wire 20 mm dia. is less than 1,- €

Processing of rolled wire rod:

Thanks to appropriate mechanical processes it is possible today to remove scale from the rolled wire rod without the use of mineral acids. The corresponding processes are avail able for this, depending on the dimensions.

A combination of bending/belt grinding is best suited for wire diameters from 5.5 to 8.0 mm
Shot blasting is predominantly used for wire diameters > 8.0 mm

Due to the uniquely short coating time with the e-phos process, the wire can enter the drawing machine at the maximum possible inlet speed. The possible speeds here are around 3.0 m/s and correspond to the max. possible pay-off speeds of rolled wire uncoilers.

Complete lines for the wire industry:

Using the e-phos technology, a finish-drawn steel wire or a skin-pass cold heading wire can be produced in a single pass starting from the wire rod by installing the corresponding machines in line.  

The perfect surface for Strip, Wire & Profiles/Tube.

STAKU products

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Questions about phosphating with e-phos?

Please contact us or request a quotation free of commitment.