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Galvanizing: Want lower zinc thickness by higher line speed

Q. We have continuous hot dip galvanising lines (Bronx-Australia). I have increased the line speed from 150 mpm to 180 mpm for 0,35 mm thick low carbon sheets, and I want to get as minimum as low coating like 45/45= 90 gr/m2 zinc coating.It is now around 110 gr/m2.Also I want to reduce the noise.

Temperature of zinc pot is increased from 460 °C to 470 C.
Gap of nozzle 0,85 mm to 1,20 mm from middle side to outer side at air knife.
Pressure of blowers on air knife point is 0,6 bar.

Is it possible to get 45/45=90 gr/m2 zinc coating on 0,35 mm sheet at 180 mpm line speed.?
I will grateful if someone can suggest the method to lower the coating thickness with those conditions mentioned above.

A. Yes. It is possible to reduce the coating. But it requires more information. From the infromation available I can suggest, reduce the nozzle size, so that the flow can be reduced.

Alternately you can increase the speed of travel, if you get proper coverage.

V. G. Rajendran
- Trichy, Tamilnadu, India

adv.
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