What to do if the bearing overheats?
What to do if the bearing overheats?
PRODUCT
The pickling passivation operation process control
by：Waxing
2020-10-02
Nitrate solution separately used to remove free iron and other metal contamination is effective, but to remove oxide, thick corrosion products, tempering membrane is invalid, such as general HNO3 + HF solution should be adopted, in order to convenient and safe in operation and fluoride can substitute for HF.
Separate HNO3 solution without corrosion inhibitor, but HNO3 + HF acid pickling, need to add a Lan -
826.
Using HNO3 + HF acid, to prevent corrosion, the concentration of the ratio of 5:1 shall be maintained.
High temperature should be lower than 49 ℃, such as, HF will evaporate.
The passivation solution, HNO3 should be controlled in 20% -
50%, according to the electrochemical tests, HNO3 concentration less than 20% treatment of passivation film quality is not stable, easy to produce pitting [
8]
, but also should not be greater than 50% HNO3 concentration, to prevent passivation.
Using one-step processing oil removal pickling passivation, although easy to operate, save time, but the pickling passivation solution (
Paste)
There will be aggressive in HF, so its ultimate footwork than protective film quality.
Allowed within a certain range adjustment in the process of pickling acid concentration, temperature and contact time.
As the growth of the acid wash time, must pay attention to the change of the acid concentration and metal ion concentration, attention should be paid to avoid acid, titanium ion concentration should be less than 2%, otherwise it will lead to serious pitting.
In general, improve pickling temperature will accelerate and improve the cleaning effect, but may also increase the risk of pollution or damage to the surface.
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