INTERN MPAPS G-19 PART I PDF

This specification covers base metal requirements, plating appearance, thickness and electrochemical potential requirements, corrosion resistance, adhesion, qualification, source approval and quality control, and shipping and handling requirements for parts in which the drawings call out this specification.

Chrome plating representing five service condition classes for corrosion resistance, related to the severity of the intended application, are included in this specification. One or more plating systems are provided for commonly plated base materials in Table I for each service condition. All options shown for a given service condition class are considered to have equivalent corrosion resistance. If a specific system option (indicated by a letter following the class designation) is not shown on a part drawing, the supplier may select the plating system option to be used. The five classes are as follows:

SC5 Exterior- Extended Severe: Exposure where long-term protection of the substrate is required and where plating is exposed to damage from denting, scratching and abrasive wear in addition to corrosive environments such as salt. Many bumpers and grille surrounds are examples of subject parts.

SC4 Exterior- Severe: Exposure that is likely to include occasional or frequent wetting by rain or dew and less exposure to road salts and other corrosive materials. Subject parts may include mirrors, grab handles, exhaust pipes, and similar components.

SC3 Exterior-Moderate: Exposure to some moisture and dew but which are generally protected from exposure to salt. Subject parts may include wiper arms and blades, window trim, ornaments, antennas, underhood components and similar parts.

SC2 Interior- Moderate: Exposure in-cab in places that are normally warm and dry but where condensation of moisture may occur and parts that are handled including control knobs, door and window handles, mirror frames, mounting brackets, and other similar parts.

SC1 Interior- Mild: Exposure inside cab in places that are generally warm and dry and rarely handled, including most interior trim pieces, dome light bezels, emblems, inside windshield moldings, and other similar parts.

Restricted Chemical Substances

All product supplied to the requirements of this specification must comply with the requirements of MPAPS B-50.

APPLICATION

This specification applies to the construction of all multi-layer Cu/Ni/Cr or Ni/Cr decorative coatings that may be applied to steel, stainless steel, aluminum, and die-cast zinc-alloy truck and engine components. Since appearance is a primary requisite, plated article must have adequate corrosion resistance to the environment in which they are exposed.