Development of Innovative Steel Grades and Their Applications in Automotive Structures

? Resistance spot weld properties
for bare NEXMET?
? Acceptable curent range, >2 kA
? Properties consistent with
expectations for given base
metal strengths

? High strain rate – In Progress
? Corrosion – No issues
? Fatigue – In testing queue

TARGETS
? Reduce mass
? Maintain roof crush
performance
? Maintain side impact
performance

* Public domain models courtesy of George Washington University
* Fully validated and correlated crash models

? Material and gage optimization was conducted to minimize mass.
? Utilizing LS-Dyna & VisualDOC design optimization software
? Side impact survival space of the baseline model is ‘Acceptable > 50 mm’,
which correlates well with the IIHS physical test result.
? Roof crush strength-to-weight ratio of 3.783 of the baseline model correlates
well with the IIHS physical test result of 3.78.

? Front Lower Control Arm (FLCA) component gage was reduced to
minimize mass while keeping the permanent sets and the buckling load
capacities of the baseline material.
? Permanent sets (Dx and Dy) were measured at ball joint after loading
(Fx = Fy = 30 kN) and then unloading.
? Buckling load capacities (LCx and LCy) were also measured at ball joint
with loading (Fx = Fy = 40 kN).
? Both loading cases have the same constraints
at two bushings.
? Abaqus FEA solver was used.

Applications of NEXMET? 1000 and 1200 Grades
? Energy absorbing parts
? Parts needing additional formability
? High strength parts
? Potential part consolidation
? Mass reduction

? NEXMET440EX Replacement of
BH240
– Similar performance for
Dent/Ding.

Current Applications:
– 2011 Suzuki MR Wagon (Front Door Outer)
– 2014 Suzuki Hustler (Rear Door Outer)
– 2011 Suzuki D-Max (Hood Outer) (Thailand)

Full Sized Truck Fender
? Down gauge with NEXMET? 440EX at 0.6 mm
? Performs better than BH 250 with 0.77 mm