What are the relevant quality requirements for electroplating (zinc, nickel and chromium)? Which is the national standard? Is there any relevant standard for surface blackening treatment?

The general requirement is the national standard, but according to different users, there are different requirements, such as chrome plating, hard chrome requiring hardness and decorative chrome requiring brightness.

National standard for zinc plating: GB 9800-88 zinc plating and cadmium chromate conversion film; Galvanizing on GB-T9799- 1997 steel.

National Standard for Nickel Plating: Nickel Plating Requirements GB 9798-1997; GB-T_ 12332- 1990_ metal coating _ nickel coating for engineering.

National standard for chromium plating: GB 1 1379-2008 chromium plating layer for engineering.

Boiling black should be called high temperature oxidation of steel, which is a chemical oxidation process with the solution of sodium hydroxide and sodium nitrite at about 140 degrees. Corresponding to the national standard: GB-T 155 19-2002 Specification and test method for black oxide film of chemical conversion film steel.