Picking is immersion of objects in dilute acid for the purpose of removing oxides or scale. The most common acids used for pickling is hydrochloric acid, Sulphuric acid and Phosphoric acid.
Hydrochloric acid, being fuming in nature, is normally used at room temperature (unheated), while both Sulphuric and phosphoric acid are used, both heated and unheated.
Hydrochloric acid (normally available at 30-33% Strength ) is used at a dilution of
1:1 or 1:2 i.e. 10-20 %
Sulphuric acid ( Normally available at 98% ) is used at a dilution of 1:4 or 1:5 i.e.20-25%
During usage, iron builds up in the pickling bath & it is a standard practice to discard them, when the Iron content (Fe) reaches 7.0% (MAX 10.0% )
The control & operation of Hydrochloric & Sulphuric acid pickling baths are given below :-
HYDROCHLORIG ACID PICKLING BATH
BATH MAKEUP
30-50Lrs / 100Lrs. Of Water
CONTROL POINTS
Strength 10-20%- check daily.
Iron content (Fe) 10% Max- Check weekly.
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment