PICKLING Sample Clauses

PICKLING. (Pump circulation is only allowed for pickling and passivation process) This is done to remove rust and scale. This is done by cleaning with water, followed by pickling with a solution containing Hydro- fluoric acid (HF) and Nitric acid (HNO3). The composition of the pickling solution and duration are adjusted after trial test on a sample piece to remove uniformly less than 25 micron thick material. Mostly the composition is HF : 5% (by mass) HNO3 : 15 to 20 % Water : Remainder This is followed by rinsing with water.