High Strength Steel Stamping Design Manual - Auto/Steel Partnership

Introduction
This manual is intended as a practical guide for automotive material engineers, product designers
and die process planners when using high strength steels for new body-in-white applications. The
guidelines herein are for normal stamping operations only, with no reference to roll forming or warm
forming processes. High strength steels in this context are defined as those in the range of 205 to
420 MPa yield strength (30-60 KSI). Applications for these steels and other advanced high strength
steels will increase as automakers worldwide look for cost effective materials for weight reduction
and improved crash energy management.
Material characteristics and die process capabilities must be understood by the product designers in
order to assure practical HSS part designs. Many of the design features needed to provide ease of
formability and dimensional stability in HSS stampings can be incorporated if known early on by
product designers. A collaborative relationship with the die process planners must be realized at the
outset of the development program.
The die process planner must communicate the required design changes to product design and plan
for a stamping process that controls buckling, springback, sidewall curl and other distortions.
A process that works for mild steel will not always produce acceptable results for HSS. The new
steels may require new stamping processes. This manual briefly covers some of these advanced die
process concepts for HSS.
The manual also provides some guidelines for die design, die construction and die tryout. In the
past, die tryout has often been left with the task of trying to make an acceptable HSS part from an
impossible combination of material, part design and die process. The result is either an unsatisfactory
part or a lower strength material substitution, and in the process, much cost and lead-time is
added to the program.
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