Tesla applies for patent for ‘ultra-hard steel’ for Cybertruck

Tesla has applied for a patent on a new “ultra-hard” steel alloy that it plans to use with the Cybertruck electric pickup truck.

One of the Cybertruck’s biggest differentiating features is the fact that Tesla plans to build it with a body and “exoskeleton” made of “ultra-hard” stainless steel:

Cybertruck is built with an exterior shell made for ultimate durability and passenger protection. Starting with a nearly impenetrable exoskeleton, every component is designed for superior strength and endurance, from Ultra-Hard 30X Cold-Rolled stainless-steel structural skin to Tesla armor glass.

The automaker said that it planned to develop its own alloy for it, and now it has applied for a patent to secure the intellectual property behind it.

In the patent application called “Ultra-Hard Cold-Worked Steel Alloy,” Tesla noted that it could be used in a vehicle with an exoskeleton:

In some embodiments, at least one exterior panel and/or body of the vehicle comprises the steel alloy. In some embodiments, the vehicle architecture is designed such that the exterior panels of the vehicle also contribute to the vehicle’s structural performance, wherein such exterior paneling of a vehicle may be referred to as an “exoskeleton.” In some embodiments, the exterior panel is or is formed from a monolithic metal sheet of the steel alloy. In some embodiments, the corrosion resistance of the monolithic metal sheet allows for the exterior panel of the vehicle to be utilized without application of an anticorrosion coating or corrosion protective agent (e.g. paint). In some embodiments, an exterior surface of the exterior panel does not comprise paint.

This leads us to believe it is indeed the alloy that Tesla plans to use for the Cybertruck.

In the patent application, Tesla shared some technical specs of the steel alloy:

In one aspect, a steel alloy composition is described. The composition includes Fe, a hardness is at least about 400 HV, and an E_pit-E_ocp corrosion resistance of at least about 500 mV in a 3 wt% sodium chloride aqueous solution.

In some embodiments, the hardness is about 420 HV to about 500 HV. In some embodiments, the Epit-Eocp corrosion resistance is about 520 mV to about 800 mV. In some embodiments, the Epit-Eocp corrosion resistance is about 520 mV to about 600 mV. In some embodiments, the composition has a yield strength of at least about 1100 MPa. In some embodiments, the composition has a ductility of at least about 60° bend angle at 1.8mm thickness. In some embodiments, martensite formation begins at about 260 K to about 340 K. In some embodiments, martensite formation begins at about 260 K to about 320 K. In some embodiments, the composition has at least about 12 vol% martensite. In some embodiments, the composition has a yield strength of at least about 1100 MPa.

The automaker claims that it outperforms other alloys:

It’s still not clear who is going to manufacture this alloy for Tesla, but there have been rumors that Steel Dynamics, which is operating a new giant plant in Texas not too far from where Tesla plans to manufacture the Cybertruck, could be a potential partner.

Tesla plans to start production of the Cybertruck at Gigafactory Texas in Austin this summer and ramp up to volume production next year.