INTERN MPAPS A-37 PDF

This specification covers requirements for stainless and heat resistant steels used in the Company's products.

NOTE: Requirements for stainless steel spring wire are covered in CEMS A-9, Steel Spring Wire. Requirements for stainless steel tubing used for exhaust, coolant, or heater applications can be found in TMS-1058, TMS-1061, and TMS-1069.

This specification also defines the mechanical and chemical finish requirements for stainless steel surfaces, including requirements for passivation, electropolished, electropolished with chrome flash, or electrolytically micro-etched, for parts requiring a decorative, color match, corrosion/heat resistant finish, or "paint-ready" stainless steel surface. Such parts might include bright reflective grab handles, sunshades (requiring color match), exhaust pipes which require both corrosion and heat resistance, or passivated stainless steel fasteners.* These finishes are classified according to the following Types (see Appendix for detailed description):

Type 1 - Electropolish only

Type 2 - Electropolish plus electrodeposited chrome flash (minimum Cr plating thickness of 0.08 μm or 0.003 mils) - applicable where color match is required

Type 3 - Electropolish plus electrodeposited chrome flash (minimum Cr plating thickness of 0.21 μm or 0.008 mils) - for high heat applications

Type 4 - Micro-etch only

Type 5 - Chemical passivation*

*NOTE: All stainless steel fasteners (i.e., bolts, nuts, washers, etc.) will be passivated in accordance with this specification unless otherwise specified on the drawing, purchase order, or in the applicable Engineering Standard Parts (ESP) document. However, passivated fasteners are not required to undergo CASS testing, unless specified.