GMW25 |
This specification defines the mechanical and material
requirements for externally threaded fasteners sized M39 and
smaller. This specification is based on ISO 898-1. However, only
property class described in this document shall be used.
Material Description. The fasteners applicable
to this specification are formed from wire steel and heat treated
by quench and tempering, as required by the property class. The
chemical composition, internal cleanliness of the steel, mechanical
properties, microstructure, and other physical properties are
described in this document.
Symbols. Not applicable.
Typical Applications. This specification
applies to bolts, screws, SEMS (bolts with washer assembly),
threaded plugs, and studs.
Remarks.
GM does not allow new release of fasteners with property class
9.8. The properties listed are for reference for legacy parts
only.
Property class 12.9 fasteners shall be released only after
consultation and approval from GM Fastener and Materials Engineers.
Usage of property class 12.9 (underlined grade) is not
permitted.
The scope of ISO 898-1 does not include threaded plugs. For the
purpose of this specification, a threaded plug can be considered a
very short bolt.
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