The e-phos surface coating process is suitable for:
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.
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.
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.
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.