What's the process flow for zinc galvanizing on stainless steel?
Author: Marisa
The process flow of stainless steel roll galvanizing mainly includes the following steps:
Degreasing: Use degreasing powder for vibration degreasing, use 90g of degreasing powder per 1L, and perform vibration degreasing for more than 20 minutes at room temperature, followed by 3 countercurrent tap water cleaning. If there is a lot of oil on the surface of the parts, it may be necessary to extend the vibration degreasing time to 60 minutes and perform multiple cleanings.
Ultrasonic degreasing: Use 100g of degreasing powder for ultrasonic degreasing at a current density of 5A/dm² and a temperature of 60℃, and then perform 3 countercurrent tap water cleanings after the end.
Pickling activation: Use 30% hydrochloric acid for activation, the time is about 3 minutes, and then perform 3 countercurrent tap water cleanings after the end.
Pre-nickel plating: Use nickel chloride and hydrochloric acid for pre-nickel plating, use 220g of nickel chloride and 18g of hydrochloric acid per 1L, and perform 8 minutes at 23℃ and a current density of 6.5A/dm².
Chemical nickel deposition: Use agent A and agent B for chemical nickel deposition, use 55ml agent A and 150ml agent B per 1L, and perform 20 seconds at pH 4.5 and 90℃
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Galvanizing: Galvanize at pH 4.2, current density 0.25, and temperature 40℃.
Cleaning and drying: Use room temperature pure water for cleaning, and then dry the workpiece at 100℃ for 3-5 minutes. Shake the workpiece once in the first minute of the drying process to prevent overlap between workpieces.
These steps ensure that the stainless steel surface is strictly cleaned, and the adhesion of the coating is enhanced through pretreatment, ultimately forming a uniform and dense galvanized layer.