GMW2 |
This specification covers the requirements for low carbon
continuous cast steel for exposed and unexposed applications and is
applicable to all low carbon steel sheet products and coated
substrates. Continuously hot or cold rolled flat products shall be
supplied as coils or sheet. Hot rolled flat products are usually
supplied in thicknesses 1.75 mm. These flat products are used
for cold forming and for manufacturing of welded tubes. Cold rolled
flat products with the appropriate surface type and surface finish
are suitable for the application of surface coatings (metallic
plating by melt dipping or thermal spray painting, electrolytic
plating, organic coating and/or other coatings). This specification
does not apply to steel for case hardening or strip applications.
Additional requirements or agreements shall be specified by
regional GM Automotive Operations (GM) business units, e.g., North
America (GMNA), Europe (GME), Latin America, Africa, Middle East
(GMLAAM), and Asia Pacific (GMAP).
Material Description. The material designation
is defined by the General Motors Worldwide (GMW) base metal
specification number, steel product type and steel grade. The steel
product type is designated by "CR" for cold rolled products, or
"HR" for hot rolled products. A numeral (1, 2, 3, etc.) will
designate the steel grade formability level. The steel grade will
correspond to the chemical and mechanical requirements as shown in
Table 1, Table 2, and Table 3. A third suffix (C) may be added
after the steel grade to designate a low carbon steelmaking
practice. The finish type, an alpha character, will designate the
finish as E (exposed), or U (unexposed). In addition, products
which are not coated shall have the word uncoated added to the
call-out after the steel type, but before the finish designation.
The above descriptive items are used together to form the coding
system. Examples of the coding system for engineering part drawings
and manufacturing engineering documents are shown in Section 8.
Typical Applications. Sheet metal parts
consisting of low carbon steel products and coated low carbon steel
substrates.
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