Description / Abstract:
This standard defines the requirements for variable thickness
rolled blanks (VTRB) and tubes (VTRT) used in the manufacture of
automotive steel parts. Variable thickness rolled blanks shall be
produced from continuous cast hot or cold rolled coils/strip that
are cold rolled to specific multiple thicknesses, annealed or
as-rolled, and galvanized (if applicable), and then leveled and cut
to specified blank sizes. Variable thickness rolled blank products
shall be used for cold formed stampings and hot formed stampings.
Variable thickness rolled tubes shall be manufactured from variable
thickness rolled blanks that are formed into circular tubes along
the longitudinal direction and joined by a laser-welded seam.
Material Description. The material designation
is specifically used for variable thickness material defined by the
thickness values, GMW base metal specification number, steel
product type, minimum yield and/or tensile strength, coating (if
applicable) and finish type. The steel product type is designated
by either Cold Rolled (CR) minimum yield strength for High Strength
Low Alloy (HSLA) grades from GMW3032M-ST-S or minimum tensile
strength/yield strength for Hot Stamped (HS) (or Hot Stamped Tube
(HT)) grades from GMW14400M-ST-S. Applications of variable
thickness rolled blanks shall be limited to unexposed parts.
Material Call-Outs. The list of material and
coating designations shown in Table 1 are the only approved
material call-outs that can be released unless Materials
Engineering and the appropriate Global Sub-System Leadership Team
approves.
Symbols. Not applicable.
Applicability. Typical applications for
variable thickness rolled blanks include (but not limited to) body
structure panels such as roof bows, cross sills, rocker panels,
cross members, tunnel reinforcements, radiator support assembly tie
bars, and B-pillars. Tubular applications include instrument panel
cross car beams.