Class 1 Plating

Class 1 plating is used to protect iron, copper, or zinc alloys against corrosive attack in rural, industrial or marine atmospheres depending upon the thickness of the nickel deposit or is used as an undercoat for chromium or one of the precious metals. Class 1 plating is used also for decorative purposes.

Class 2 Plating

Class 2 plating is used for wear resistance, abrasion resistance and such incidental corrosion protection of parts as the specified thickness of the nickel plating may afford. Heavy deposits of the Class 2 plating, especially when the Watts bath process is employed, may be used for buildup of worn or undersized parts, or for salvage purposes, and to provide protection against corrosive chemical environments.

Processes used for cleaning and nickel plate deposition on parts heat treated to 160 000 psi (HRC 36) or greater should incorporate practices and procedures to minimize hydrogen embrittlement. Unless otherwise specified on the engineering drawing, parts heat treated to an ultimate tensile strength greater than 240 000 psi (HRC 48) shall not be plated in accordance with this specification due to potential susceptibility to hydrogen embrittlement.