Metal finishing Q&As since 1989

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CONTINUOUS PICKLING PROCESS

 

I WISH TO HAVE THE PROCESS DETAILS ON CONTINUOUS PICKLING LINE OF MILD STEEL COILS USING HCL. KINDLY MAIL ME AT THE EARLIEST REGARDING THIS MATTER. What I'm looking for is the technical details..

1)How many tanks does the pickling line have?
2)What should be the acid concentration of HCL
3)How long should the coil take to pass through the acid tank
3)How does blushing on steel take place & why
4)Is there any speed at which the line should be moving
5)How long can the material be exposed to air before entering the next tank. Basically I'm looking for the process details These are few of my doubts. Hoping to hear from you in this regard at the earliest.

Thank you,

GEORGE JACOB
- Chennai, TamilNadu, INDIA

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The Canning Handbook [on eBay, Amazon, AbeBooks], W. Canning, plc, Birmingham, has an excellent section on cleaning and pickling, which will answer most of your questions. Questions about speed of the line and concentrations depend on how you engineer the plant, and the particulars of the steel that is being treated. Blushing is probably "flash rusting", and must finally be handled chemically before the final drying sequence.

  
Tom Pullizzi
Falls Township, Pennsylvania
 

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Tom, sorry to W Canning is no more - they were purchased by Macdermid and now trade under that banner. This is too quick for the on-line phone books to keep up with as well so getting hold of them may be tricky. However they do still sell the Canning Hand Book.

Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England

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Couldn't find the book that you have suggested. Could you suggest any other book or any person whom I could contact to get more details on pickling process

Regards,

George Jacob
- Chennai, TamilNadu, India
 

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1)How many tanks does the pickling line have? Normally the tanks ranged from 3 to 6 tanks.
2)What should be the acid concentration of HCl Acid concentration is variable from 2~4% for the last tank and 14~17% for the first tank.
3)How long should the coil take to pass through the acid tank It is based on the line speed normally 30 sec. 4)Is there any speed at which the line should be moving It is depending on the pickling quality considering the steel grade. Effective speed is 80~120 meter per min.

Hoping this information is useful for you.

Nabil Sahlab
- Alexandria, Egypt