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Pickling and washing action in hot dip galvanizing process
Time:2017-8-1 10:23:12
The hot dip galvanizing process should be washed after pickling. The purpose of this washing is to reduce excessive acid into the plating aid, and to reduce the pH value of the plating aid. Two is to reduce excessive iron is brought into the plating agent, pickling after washing is very important to protect plating agent, so the use of plating process must be washed after pickling.
In the production process, due to the continuous acid washing water into the pH value of less than, which will be on the back of the plating adversely affected, because the water is acidic, will make further steel pickling, make the iron ion more washed into the water, so that more iron in plating solution. The effect of excessive iron content on the galvanizing process will be explained later, but many manufacturers use the wrong method when adjusting the washing water.
To keep constantlychanging washing water, we dont recommend adding sodium hydroxide, but adding ammonia water. If you add sodium hydroxide, will enable the washing water into the ferrous chloride and ferric hydroxide, ferric hydroxide containing water in the drying can not be ruled out, into the liquid zinc will generate a lot of dust. The ammonia water into the washing water, reacts with hydrochloric acid in water to form ammonium chloride, which is a component of the plating aid.
We only need to avoid the help of the plating agent to destroy the balance of zinc and ammonia because of the excessive ammonium chloride.
Also note that, after pickling with hot acid, rinse with hot water instead of heating and rinse with cold water after pickling. And wash the best water in flowing water, two times the effect of washing better.