How can the star stainless screw surface handle the salt spray test time?

After the production of star stainless screw, the general treatment method is to first remove the oil with the degreasing agent, then use the polishing agent for the bright light treatment, and then package and ship after drying. For screws that only remove oil and shine, you can usually pass the salt spray test for 48-72 hours. However, in daily work, customers often ask us if there is any way to extend the salt spray test time of stainless steel screws. Because many foreign customers, because the product needs the environmental impact of shipping, in order to ensure the quality of the product delivery, the salt spray test must reach more than 150 hours.

In order to achieve this, it is necessary to passivate the star stainless screw. The principle of passivation treatment is that after the stainless steel surface is immersed in contact with the passivation solution, a microchemical reaction is generated on the surface of the stainless steel, and the original chemically active metal surface is transformed into a chemically inert metal surface, so that it is difficult to reproduce with the external substance. chemical reaction. Thereby achieving long-term rust prevention.

After passivation of 304 star stainless screw, the concentration of salt spray at 5%-15% under normal conditions can be at least 150 hours. The passivation of stainless steel is essentially pickled. The cleaning after passivation is very important. It is also very important for stainless steel to be rusted when it is acid, so if it is cleaned after passivation (usually ultrasonic cleaning), salt spray on stainless steel Erosion will not be too great, at least for an estimated 150 hours.

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