Passivation treatment of seamless steel pipe
Passivation is the last process step and the key step in chemical cleaning of steamless steel pipe.
The boiler after pickling, water washing, rinsing, metal surface is very clean, very active, easy to suffer from corrosion, so it must be immediately passivation treatment, so that the cleaned metal surface generated protective film, slow down corrosion.
Use: For stainless steel comprehensive pickling passivation treatment, remove all kinds of oil, rust, oxide skin, welding spot and other dirt, the surface becomes uniform silver white after treatment, greatly improve the corrosion resistance of stainless steel, suitable for various types of stainless steel parts, plates and equipment.
SIMPLE operation, easy to use, economical and practical, and the addition of efficient corrosion inhibitor, fog inhibitor, prevent metal corrosion and hydrogen embrittering phenomenon, and inhibit the production of acid fog. Especially suitable for small complex workpiece is not suitable for paste, superior to the market similar products.
According to the stainless steel material and the severity of the oxide skin, can be used with the stock solution or according to the ratio of 1:1 ~4 water diluted after use; Ferrite, martensite and austenitic stainless steel with low nickel content (such as 420, 430, 200, 201, 202, 300, 301, etc.) were diluted and used, while austenitic stainless steel with high nickel content (such as 304, 321, 316, 316L, etc.) was soaked in stock solution; Commonly used after normal temperature or heating to 50 ~ 60 degrees, immerse 3-20 minutes or longer (specific time and temperature users according to their own trial conditions), to the surface completely remove dirt, into a uniform silvery white, and the passivation film forming uniform, take out after processing is completed, rinse off with clear water, best to use alkaline or flush and whitewash.
Passivation: The process of forming a trivalent or hexavalent chromized layer on the surface of a metal by the action of a chromate solution, called passivation, also called chroMIzation. Used for aluminum, magnesium and its alloy processing, steel can also form chromated layer, but rarely used alone, often and phosphating matching use, to close the pores of the phosphating layer, so that the bare steel passivation in the phosphating layer, to inhibit the corrosion of residual phosphating accelerant, further increase the protection ability. Passivation with potassium dichromate solution (2 ~ 4 g/L, sometimes also added 1 ~ 2 g phosphoric acid), at 80-90 degrees Celsius immersion for 2-3 minutes to remove, the wash with water can be.