Cross members in AHSS for strength, lightweighting & safety

Cross members can further stiffen the car body, transfer side impact loads, and, in BEVs, protect battery packs. With their high strength, cross members made in AHSS and UHSS steels can increase both crash performance and vehicle responsiveness.

Doubling the crash load transfer performance of EV cross members

To protect floor-mounted EV battery packs during a side crash, cross members in the passenger compartment should not deform, but instead transfer the force to the opposite side of the car.

SSAB simulation for Docol® 1700 martensitic steel cross members show that a profile with a 15xt (radii in mm times thickness of the cross member) performs better than 1xt, with material thickness adjusted so the overall weight of the different profiles are the same.

An optimized cross member can more than double the crash load transfer performance over a square-shaped profile. To see the profiles of the cross member beams tested here, including the best performing profile, contact Docol.

Cross members transferring a side impact to the opposite side of the car

Cross members transferring a side impact to the opposite side of the car.

Force displacement curves of the simulated Docol® CR 1700M cross members.

Force displacement curves of the simulated Docol® CR 1700M cross members.

BEV cross member in 1500M-EG meets safety and lightweighting goals

An automotive OEM needed a high-strength solution for a combination seat cross member and reinforcement for its BEV. They selected Docol® CR1500M-EG in 1.35 to 1.90 mm thicknesses. The resulting cold-formed 1500MPa cross member/reinforcement is both light-in-weight and high in performance during crash tests. Plus – in a first for passenger cars – the cross member/reinforcement was made as part of a trial using SSAB Fossil-free™ steel. The result is a virtually emissions-free, cost-efficient solution using the exclusive electrogalvanized Docol® martensitic grade for corrosion resistance.

 
Cross member with 1500MPa tensile strength needs to only be 1.35 to 1.90 mm thick to deliver high crash performance at low weight

Cross member with 1500MPa tensile strength needs to only be 1.35 to 1.90 mm thick to deliver high crash performance at low weight.

VW ID Buzz’s 2000MPa cross members protect EV battery

These three newly designed cross members leverage the superior 2000MPa tensile strength of Docol® PHS 2000 steel to help protect the VW ID Buzz’s battery pack. The cross members have excellent crash test performance for side impacts while being only 1.8 mm thick, contributing to the EV’s lightweighting goals.

 
The hot-formed cross members in Docol® PHS 2000 delivered impressive side impact test results and weight savings for the VW ID Buzz bus.

The hot-formed cross members in Docol® PHS 2000 delivered impressive side impact test results and weight savings for the VW ID Buzz bus.

Cross members: steel grade suggestions

Current material
Suggested upgrades Advantages Additional benefits
PHS
DP 
PHS2000
CR1500M
CR1700M
Lightweighting
Safety
Functional upgrades to high strength grades. MS grades cold-formed.
HR355-420MC
HR700LA
HR800HER (CP)
HR1200M
HR1500M
HR500HE (+EG)
Lightweighting Fatigue
Crash worthiness

Get AHSS/UHSS samples – fast

In just one to two weeks, you can get trial samples of most of our commercially available AHSS/UHSS steel grades – plus some of our newest, not-yet-released steels.

Other automotive applications

Our steel grades serve specific design purposes and are chosen by designers for a wide range of automotive applications.