What is stainless steel balls passivation?

The way to make stainless steel ball passivation is to clean it with acid and alkali solution. The purpose of pickling is to remove oxide layer which is produced by hot-treated stainless steel and welding heat-affected zone and which will affect the corrosion resistance. There are two method to pickling, which is pickling solution and pickling cream. Pickling with water-acid solution can be divided into dipping and brushing.

Dipping is to immerse the object, usually smaller equipment and components, in the pickling solution for 25 to 45 minutes and rinse with water after taking out, which is suitable for smaller equipment and parts. Unlike dipping, brushing is to use a brush to dip the pickling solution to scrub until the object is white and silvery and then rinse with water, which is more suitable to large object or equipment. Pickling with pickling cream can be also used for large equipment, which is to apply the prepared pickling cream to the weld and the surface of the heat affected zone of the weldment and rinse with water after few minutes.

Passivation takes place after pickling. The formula of the passivation solution is: 5 ml of nitric acid, 1 g of potassium dichromate, and 95 ml of water with room temperature and 1 hour of processing time. The processing method is to scour the passivation solution on the surface of the weld, and then wipe it  carefully with a cloth after rinsing it with cold water, then rinse it again with hot water and blow-dry it. Stainless steel balls are silvery in appearance and have high corrosion resistance after passivation processing.