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.