This specification defines corrosion resistant stainless steels primarily used in automotive exhaust applications. It covers cold and hot rolled, uncoated and coated stainless steel sheets and tapes (strips) for exhaust systems, used at GM units worldwide. The specification includes chemical composition, physical and mechanical properties, heat treatment and characteristic properties. Parameters for surface treatment, welding and filler materials are not covered with this specification.

Material Description. This specification describes stainless steels typically used in automotive exhaust systems. Stainless steels are iron base alloys containing sufficient chromium to form a passive film of surface associated oxygen. Stainless steels are specified for applications which require corrosion, high temperature oxidation resistance or high temperature strength.

These materials are suitable for cold forming and bending. The stabilized and low carbon stainless steels can be readily welded with minimal risk of sensitization. Both heat treatable and non-heat treatable stainless steels are described in this specification.

Additional requirements or agreements may be specified by local business units.

Material Identification. The material designation is defined by the GMW base metal specification number, steel grade and coating (if required).

Example: GMW3161M-ST-S-X2CrTi12-AL30

Symbols. Not applicable.

Applicability. These materials are typically used in exhaust components such as take down pipes, hangers, flanges, gaskets, catalytic converters, muffler internals, and are specified based on the expected part metal temperature and environmental exposure. Cross reference specifications are listed in Appendix C, Table C1. Additional details regarding typical use are described in Appendix D.

Remarks. Not applicable.